Maritime Geothermal Nordic PC Series Manual

ISSUE 03: 1-Oct-2021 Page 1 002291MAN-03
Maritime Geothermal Ltd.
P.O. Box 2555, 170 Plantation Road
Petitcodiac, NB E4Z 6H4
[phone]
PC-Series Pool Conditioner
Pool Room Dehumidifier with Air or Pool Water Heat Recovery
GEN2 Control System
Model Sizes 45-80
[email protected]
www.nordicghp.com
002291MAN-03
ISSUE 03 1-Oct-2021
Installation and Service Manual
optional outdoor unit
for air conditioning

ISSUE 03: 1-Oct-2021 Page 2 002291MAN-03
AC2—65—P—1/6—SDE—xx
WARNING: Ensure all access panels are in place and properly secured before applying power to the unit.
Failure to do so may cause electrical shock.
WARNING: Before performing service or maintenance on the system, ensure all power sources
are DISCONNECTED. Electrical shock can cause serious personal injury or death.
WARNING: Refrigeration systems contain refrigerant under high pressure and as such can be hazardous
to work on. Only qualified service personnel should install, repair, or service the heat pump.
CAUTION: Safety glasses and work gloves should be worn at all times whenever the system is serviced.
A fire extinguisher and proper ventilation should be present whenever brazing is performed.
CAUTION: Venting refrigerant to atmosphere is illegal. A proper refrigerant recovery system must be
employed whenever repairs require removal of refrigerant from the equipment.
SAFETY PRECAUTIONS
Model Nomenclature
PC—65—P—1S—T—KDERS—xx
Series:
PC = Pool Conditioner
Nominal Size:
45 = 031 compressor
55 = 042 compressor
65 = 054 compressor
75 = 061 compressor
80 = 067/070 compressor
Refrigerant:
P = R410a
Indoor Loop (Pool)
Exchanger:
T = Titanium
Air Coil:
K = Coated
Blower Type:
D = Direct Drive
Blower Motor:
E = ECM (Variable Speed)
Air Return:
R = Right Side
Air Discharge:
S = Side
T = Top (up)
D = Down
Revision:
01, 02 etc.
Voltage Code:
1 = 208/230-1-60
2 = 208-3-60
4 = 460-3-60
6 = 220-1-50
7 = 380-3-50
Compressor:
S = single stage scroll
Series:
AC2 = PC Outdoor Condenser
Nominal Size:
45 = for PC-45
55 = for PC-55
65 = for PC-65
75 = for PC-75
80 = for PC-80
Voltage Code:
1/6 = 220/230-1-50/60
Air Coil:
S = Standard
K = Coated
Blower Type:
D = Direct Drive
Blower Motor:
E = ECM (Variable Speed)
Revision:
01, 02 etc.

ISSUE 03: 1-Oct-2021 Page 3 002291MAN-03
Maritime Geothermal Ltd. has a continuous improvement policy and reserves the right to modify specification
data at any time without prior notice .
APPLICATION TABLE - PC-SERIES INDOOR UNIT
MODEL REFRIGERANT VOLTAGE STAGES INDOOR COIL COILS/BLOWER/
AIR RETURN
AIR
DISCHARGE REVISIONS
PC-45 P
1
2
4
6
7
S T K D E R
T
S
D
09
PC-55 P
1
2
4
6
7
S T K D E R
T
S
D
09
PC-65 P
1
2
4
6
7
S T K D E R
T
S
D
09
PC-75 P
1
2
4
7
S T K D E R
T
S
D
09
PC-80 P S T K D E R
T
S
D
09
This manual applies only to the models and revisions listed in this table.
1
2
4
6
7
APPLICATION TABLE - OPTIONAL AC2-SERIES OUTDOOR UNIT
MODEL REFRIGERANT VOLTAGE AIR COIL BLOWER TYPE BLOWER MOTOR REVISIONS
AC2-45 P 1/6 S
K D E 01
AC2-55 P 1/6 S
K D E 01
AC2-65 P 1/6 S
K D E 01
AC2-75 P S
K D E 01
AC2-80 P 1/6 S
K D E 01
This manual applies only to the models and revisions listed in this table.
1/6
APPLICATION TABLE - FIRMWARE AND PC APP
Firmware Version* Associated PC APP Version
MGT GEN2 Bootload Firmware V3.66+ MGT GEN2 PC APP V2.00+

ISSUE 03: 1-Oct-2021 Page 4 002291MAN-03
Tables, Figures, & Documents ........................... 5
System Description ................................................... 6
General Overview ................................................................... 6
1. Air Reheat Mode ................................................................. 6
2. Pool Water Heat Mode ........................................................ 6
3. Heat Rejection Mode (AC2-Series Outdoor Unit) ............... 6
Auxiliary Air Heat .................................................................... 6
Operating Mode Tables .......................................................... 7
PC Sizing ......................................................................... 8
Pool Surface Area ................................................................... 8
PC Unit Sizing ......................................................................... 8
Plenum Heater Sizing ............................................................. 9
Installation Basics .................................................... 10
Sample Bill of Materials ........................................................ 10
Unpacking the unit ................................................................ 10
PC Indoor Unit Placement .................................................... 10
Optional AC2 Outdoor Unit Placement ................................. 11
Outdoor Fan Speed Reduction ............................................. 11
Wiring ............................................................................... 12
PC-Series Power Supply Connections .................................. 12
Optional AC2 Outdoor Unit: Power Supply Connections ...... 12
Auxiliary Plenum Heater: Power Supply Connections ........... 12
Auxiliary Plenum Heater: Signal Connections ....................... 12
Pool Pump Signal Connections ............................................ 12
Control Transformer .............................................................. 13
Optional AC2 Outdoor Unit: Signal Connections .................. 13
Air Thermostat Connections .................................................. 13
Accessory Connections ........................................................ 13
Disable Switch (field installed) .............................................. 13
Air Conditioning with Cold Water .......................................... 13
002298CDG - Typical PC-Series Wiring Connections .......... 14
Piping ............................................................................... 15
Pool Water Lines ................................................................... 15
Condensate Drain ................................................................. 15
Simultaneous Pool/Hot Tub Heating ..................................... 15
Air Conditioning with Cold Water .......................................... 15
002297PDG - Typical Loop Connections - PC Series .......... 16
001824PDG - PC-Series Connections to Pool & Hot Tub ..... 17
001045CDG - PC-Series Cold Water Cooling Connections ... 18
Ductwork ........................................................................ 19
Duct Systems - General ........................................................ 19
Supply Duct System .............................................................. 19
Return Duct System ............................................................... 19
Plenum Heater ....................................................................... 19
Duct Sizing Guide .................................................................. 21
AC2-Series Outdoor Unit Line Set .................. 22
Line Set Interconnect Tubing ................................................ 22
Oil Traps ............................................................................... 22
Pipe Insulation ...................................................................... 22
Silver Soldering Line Sets ..................................................... 22
Pressure Testing ................................................................... 22
Vacuuming the System .......................................................... 22
Charging the System ............................................................. 23
Operation ....................................................................... 24
BACnet Control ..................................................................... 24
Air Thermostat Operation ...................................................... 24
Changing Air Setpoints Using PC App .................................. 24
Air Thermostat Setup ............................................................ 24
Pool Water Temperature Control .......................................... 25
1. Pool water: Setpoint Control ............................................. 25
Table of Contents
Setpoint Control Method 1 - Indoor Loop .......................... 25
Setpoint Control Method 2 - External HTS/CTS ................ 25
2. Pool Water: Signals Control .............................................. 25
PC Application (PC App) ...................................... 26
LCD Interface & Menus ......................................... 38
BACnet Interface ........................................................ 40
Startup Procedure .................................................... 44
Pre-start Inspection ............................................................... 44
Unit Startup ........................................................................... 44
Startup Record ...................................................................... 45
Routine Maintenance ............................................. 47
Troubleshooting Guide ......................................... 48
Repair Procedures ................................................... 61
Pumpdown Procedure .......................................................... 61
General Repair Procedure .................................................... 61
Vacuuming & Charging Procedure ....................................... 61
Compressor Replacement Procedure ................................... 62
Outdoor Fan Replacement Procedure .................................. 62
Control Board Replacement Procedure ................................ 63
LCD Interface (Display) Board Replacement Procedure ....... 64
Model Specific Information ................................ 65
Shipping Information ............................................................. 65
Refrigerant Charge ............................................................... 65
Required Pool Water Flow Rates .......................................... 65
Control Temperature Limits .................................................. 65
AC2-Series Outdoor Unit Sound Levels (dBA) ..................... 65
Pool Water Pressure Drop .................................................... 65
Capacity Ratings ................................................................... 66
Electrical Specifications ........................................................ 67
Indoor Airflow ........................................................................ 68
Wiring Diagram (208/230-1-60) ............................................ 69
Electrical Box Layout (208/230-1-60) .................................... 70
Wiring Diagram (208-3-60) ................................................... 71
Electrical Box Layout (208-3-60) ........................................... 72
Wiring Diagram (460-3-60) .................................................... 73
Electrical Box Layout (460-3-60) ........................................... 74
Wiring Diagram (220-1-50) .................................................... 75
Electrical Box Layout (220-1-50) ........................................... 76
Wiring Diagram (380-3-50) .................................................... 77
Electrical Box Layout (380-3-50) ........................................... 78
AC2 (Outdoor Condenser) Wiring Diagrams .......................... 79
PC-Series Refrigeration Circuit - Pool Water Heat Mode ...... 80
PC-Series Refrigeration Circuit - Air Reheat Mode ............... 81
PC-Series Refrigeration Circuit - Heat Rejection Mode ........ 82
Dimensions ........................................................................... 83
Appendix A: Control Board Description ...... 84
Appendix B: USB Driver Installation ............ 88
Appendix C: PC App Installation .................... 89
Appendix D: Updating Firmware ...................... 90
Updating Firmware Using PC App ........................................ 90
Updating Firmware Using Jumper Pins .................................. 92
Warranty ......................................................................... 93

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Tables, Figures, & Documents
Table 1 - Pool Conditioner Operating Modes (with optional AC2 outdoor condenser) ............................. 7
Table 2 - Pool Conditioner Operating Modes (without optional AC2 outdoor condenser) ........................ 7
Table 3 - Step by Step Pool Evaporation Rate Calculation ...................................................................... 8
Table 4 - PC Typical Sizing (60 Hz) ......................................................................................................... 8
Table 5 - PC Typical Sizing (50 Hz) .......................................................................................................... 8
Table 6 - Activity Factor ........................................................................................................................... 8
Table 7 - Evaporation Rate Chart (50% RH) ........................................................................................... 9
Table 8 - Evaporation Rate Chart (60% RH) ........................................................................................... 9
Table 9 - Plenum Heater Sizing ............................................................................................................... 9
Table 10 - PC-Series Power Supply Connections ................................................................................. 12
Table 11 - AC2-Series Power Supply Connections ............................................................................... 12
Table 12 - Plenum Heater Signal Connections ...................................................................................... 12
Table 13 - Pool Pump Signal Connections ............................................................................................ 12
Table 14 - Control Transformer ............................................................................................................. 13
Table 15 - Outdoor Unit Signal Connections ......................................................................................... 13
Table 16 - Air Thermostat Connections ................................................................................................. 13
Table 17 - Duct Sizing Guide ................................................................................................................. 21
Table 18 - Interconnect Line Set Tools .................................................................................................. 22
Table 19 - Extra Charge Required ......................................................................................................... 23
Table 20 - Extra Charge Chart .............................................................................................................. 23
Table 21 - BACnet Objects - Control Signals (Read/Write) .................................................................... 40
Table 22 - BACnet Objects - Operation Mode Description (Read Only) ................................................. 40
Table 23 - BACnet Objects - Data (Read Only) ...................................................................................... 41
Table 24 - BACnet Objects - Alarm Descriptions (Read Only) ............................................................... 42
Table 25 - BACnet Objects - Fault Descriptions (Read Only) ................................................................. 43
Table 26 - Shipping Information (PC) .................................................................................................... 65
Table 27 - Shipping Information (AC2 Outdoor Unit) ............................................................................. 65
Table 28 - Refrigerant Charge ............................................................................................................... 65
Table 29 - Required Pool Water Flow Rates ......................................................................................... 65
Table 30 - Control Temperature Limits .................................................................................................. 65
Table 31 - AC2-Series Outdoor Unit Sound Levels (dBA) ..................................................................... 65
Table 32 - Pool Water Pressure Drop (all model sizes) ......................................................................... 65
Table 33 - PC-Series Capacity Ratings (60 Hz) .................................................................................... 66
Table 34 - PC-Series Capacity Ratings (50 Hz) .................................................................................... 66
Table 35 - PC-Series Electrical Data ..................................................................................................... 67
Table 36 - Plenum Heater Electrical Data .............................................................................................. 67
Table 37 - Indoor Airflow ........................................................................................................................ 68
Table 38 - Indoor Airflow for Auxiliary Heat ............................................................................................ 68
Table 39 - Indoor Airflow for Fan Recirculation ...................................................................................... 68
Table 40 - Indoor Airflow for Emergency Heat ........................................................................................ 68
Table A1 - Control Board Connector Descriptions (Top) ........................................................................ 8 5
Table A2 - Control Board Connector Descriptions (Left Side) .............................................................. 85
Table A3 - Control Board Connector Descriptions (Bottom) .................................................................. 86
Table A4 - Control Board Connector Descriptions (Right Side) ............................................................. 87
Figure 1 - Floor Supply Ducts With Elevated Return ............................................................................. 20
Figure 2 - Elevated Supply Ducts With Elevated Return ....................................................................... 2 0
Figure 3 - BAPI STAT4 Air Thermostat ................................................................................................. 24
Dimensions ............................................................................................................................................ 83
002298CDG - Typical PC-Series Wiring Connections ............................................................................ 14
002297PDG - Typical Loop Connections - PC Series ............................................................................ 16
001824PDG - PC-Series Connections to Pool & Hot Tub ..................................................................... 17
001045CDG - PC-Series Cold Water Cooling Connections ................................................................... 18
001423SCH - PC-Series (GEN2) Schematic Diagram 208/230-1-60 .................................................... 69
001424ELB - PC-Series Electrical Box Diagram 208/230-1-60 ............................................................. 70
001825SCH - PC-Series (GEN2) Schematic Diagram 208-3-60 ........................................................... 71
001826ELB - PC-Series Electrical Box Diagram 208-3-60 .................................................................... 72
002292SCH - PC-Series (GEN2) Schematic Diagram 460-3-60 ........................................................... 73
002293ELB - PC-Series Electrical Box Diagram 460-3-60 .................................................................... 74
001425SCH - PC-Series (GEN2) Schematic Diagram 220-1-50 ........................................................... 75
001426ELB - PC-Series Electrical Box Diagram 220-1-50 .................................................................... 76
002294SCH - PC-Series (GEN2) Schematic Diagram 380-3-50 ........................................................... 77
002295ELB - PC-Series Electrical Box Diagram 380-3-50 .................................................................... 78
002261SCH - PC Outdoor Condenser (AC2-Series) 1-Fan Schematic Diagram .................................. 79
002262SCH - PC Outdoor Condenser (AC2-Series) 4-Fan Schematic Diagram .................................. 79
000352RCD - PC-Series Refrigeration Circuit - Pool Water Heat Mode ............................................... 80
000353RCD - PC-Series Refrigeration Circuit - Air Reheat Mode ......................................................... 81
000354RCD - PC-Series Refrigeration Circuit - Heat Rejection Mode .................................................. 82
Tables
Figures
Documents

ISSUE 03: 1-Oct-2021 Page 6 002291MAN-03
General Overview
The PC-Series pool conditioner is a pool room dehumidifi-
er, that cools and dehumidifies pool room air whenever it is run-
ning. This is an energy-efficient alternative to the traditional
method of controlling pool room humidity, which involves ex-
hausting moist air and introducing fresh outside air that must
then be heated or cooled to the correct temperature.
The vapour compression refrigeration cycle used to cool
the air (similar to that that used in air conditioners or refrigera-
tors) produces excess heat, equal to the amount of electrical
energy put in to run the compressor.
This heat can be put into one of three places: back into the
pool room air, into the pool water, or sent to the outdoor air via
an optional outdoor condenser. There are therefore three oper-
ating modes. The operating mode is determined according to
the inputs from the supplied communicating room air thermostat
that measures the room temperature and humidity, and an inter-
nal routine or external aquastat that measures pool water tem-
perature. The air thermostat also has a user interface that al-
lows changing the air temperature and humidity setpoints.
Air coils are e-coated for corrosion protection, and pool
water heat exchanger is titanium/PVC for a corrosion resistance
that is much superior to steel, copper, or CuNi. The cabinet is
powder coated galvanized sheet metal, which achieves com-
plete coverage and has a corrosion protection that is superior to
stainless steel due to the potential for impurities in stainless
material. Control is overseen by the Nordic GEN2 programma-
ble control board, which has many advanced features like laptop
connectivity via the free PC App software, data logging & gra-
phing, and electronic temperature & pressure sensors. An elec-
trically commutated (ECM) blower motor with adjustable airflow
is standard.
An optional AC2-Series outdoor condenser is available as
an accessory, which enables Heat Rejection Mode (see below).
1. Air Reheat Mode
In this mode, air is cooled and dehumidified by the PC’s
internal refrigerant-to-air evaporator coil. Air is then reheated
with the PC’s internal refrigerant-to-air condenser coil. There is
a net heating effect on the air, equal to compressor power input.
The air emerges drier and warmer than it went in.
2. Pool Water Heat Mode
In this mode, air is cooled and dehumidified by the PC’s
internal refrigerant-to-air evaporator coil. Heat is rejected to
pool water, some portion of which is circulated through the
PC’s internal refrigerant-to-water condenser coil by the pool
pump. The air emerges drier and cooler than it went in, and
water emerges warmer than it went in.
Unlike in firmware prior to v3.60, priority is now always
pool water heating, since the previously available air heat priori-
ty setting resulted in excessive compressor cycling and mode
switching. Therefore if there is demand for both air and pool
water heating, the pool water heating demand will be satisfied
first.
Typically, while performing dehumidification the PC-
Series unit will provide all of the pool water heating re-
quired for an indoor pool, with no auxiliary pool water heat-
ing required. Auxiliary heat will be required for the pool
room air during colder weather.
System Description
3. Heat Rejection Mode
(AC2-Series Outdoor Unit)
In this mode, air is cooled and dehumidified by the PC’s
internal refrigerant-to-air evaporator coil. Heat is rejected to an
optional outdoor condenser unit (AC2-Series), which is
available as an accessory from Maritime Geothermal Ltd., and
is often only necessary in warmer climates or in buildings with a
high solar gain. There is automatic detection of the outdoor
condenser by the PC unit. If not present, either air reheat mode
or pool water heat mode will be engaged instead, according to a
user setting accessible through the PC App software.
There are two sizes of outdoor unit, one for PC sizes
45/55 and one for PC sizes 65/75/80. The AC2 contains only
the outdoor refrigerant-to-air heat exchanger (air coil), and an
ECM hub motor axial fan. The hub motor fan is speed con-
trolled by the PC’s GEN2 control board based on refrigerant
discharge pressure. This results in maximum airflow when
needed, while allowing reduced airflow at other times for noise
and power savings.
Because the outdoor unit is only used for heat rejection,
there is no outdoor expansion valve (EEV) or defrost cycle logic
necessary. Although the NORDIC AC2 and ACE outdoor units
look similar, the AC2 is used with the Nordic PC series, and the
ACE (which includes the outdoor EEV and defrost logic) is used
with Nordic air source heat pumps like the ATW, ATA, and ATF
series.
Open loop (well water or other cold water loop) may be
used in place of an outdoor unit for heat rejection; see Piping
chapter.
Auxiliary Air Heat
While PC is operating in any mode, auxiliary heat (usually
an electric plenum heater) will also be engaged if the air temper-
ature drops below the air heat Auxiliary setpoint.
The first function of the plenum heater is to act as an auxil-
iary heat source for the pool room air. It will provide additional
air heating on cold days when the pool water requires all or
most of the unit’s heat output.
The second function of the plenum heater is to provide
emergency heat should a problem occur that causes the PC unit
to be locked out on a safety control. The control board automat-
ically controls the auxiliary heat, allowing the plenum heater to
function even if the PC compressor is locked out and not opera-
tional.
Electric plenum heaters are available as accessories in 5,
7, 10, 15 and 20kW sizes. See the Sizing, Wiring, and Duct-
work sections. These heaters are installed in the air dis-
charge ductwork outside the PC unit.
Other types of air heat (gas, hydronics from a water-to-
water geothermal system) can be used, and should be con-
trolled by the 2 stages of dry contacts marked “Plenum Heater”
on the terminal strip in the PC unit.

ISSUE 03: 1-Oct-2021 Page 7 002291MAN-03
TABLE 2 - Pool Conditioner Operating Modes (without optional AC2 outdoor condenser)
AIR DEMAND (from air thermostat) POOL WATER HEAT
DEMAND (from set-
point control routine
or aquastat)
PC OPERATING MODE
DEHUMIDIFY HEAT
OFF
X
POOL WATER HEAT MODE
X
AIR REHEAT MODE
X X
POOL WATER HEAT MODE
X SELECTABLE: AIR REHEAT OR POOL WATER HEAT MODE
X X POOL WATER HEAT MODE
X X AIR REHEAT MODE
X X X POOL WATER HEAT MODE
TABLE 1 - Pool Conditioner Operating Modes (with optional AC2 outdoor condenser)
AIR DEMAND (from air thermostat) POOL WATER HEAT
DEMAND (from set-
point control routine
or aquastat)
PC OPERATING MODE
DEHUMIDIFY COOL HEAT
OFF
X
POOL WATER HEAT MODE
X
AIR REHEAT MODE
X X POOL WATER HEAT MODE
X HEAT REJECTION MODE
X X POOL WATER HEAT MODE
X X AIR REHEAT MODE
X X X POOL WATER HEAT MODE
X
HEAT REJECTION MODE
X X
POOL WATER HEAT MODE
X X HEAT REJECTION MODE
X X X POOL WATER HEAT MODE

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PC Sizing
Pool Surface Area
As the square footage of the pool increases, the
evaporation rate will increase proportionally. This is due to the
increase in size of the surface water / air contact area. The
depth, shape, and total volume of the pool do not affect the
evaporation rate.
PC Unit Sizing
The amount of evaporation occurring in a residential pool
application of a given size is governed mainly by the tempera-
tures at which the air and water are maintained. It is common
practice to keep the air temperature 2°F above the pool water
temperature. The lower the air temperature is in comparison to
the water temperature, the higher the evaporation rate will be.
The evaporation rate of the pool increases when the following
occur:
1) Pool water temperature increases
2) Activity level / wet floor area increases
3) Airflow across pool surface increases
4) Room air temperature decreases
5) Room relative humidity level decreases
1) Pool water temperature: The temperature of the pool
water in relation to the air temperature is one of the most
important factors in determining overall evaporation rate from
the pool. As the room air temperature decreases in relation
to the pool water, the evaporation rate will increase
dramatically. The normal pool water temperature range for
private pool use is from 78°F to 82°F. The air temperature
should be kept 1° to 2°F above the water temperature for the
most economical operation of the pool conditioner.
2) Activity level / wet floor area: During pool use, water will
be drawn out of the pool by the action of swimmers leaving
and re-entering the pool during normal activities. This water
will accumulate on the floor surrounding the pool and will
contribute to the overall surface exposed to the air for
evaporation purposes. If the pool floor is heated then the
evaporation rate will exceed that of the pool itself and this
extra wetted area should be considered in sizing the pool
conditioner.
TABLE 4 - PC Typical Sizing (60 Hz)
Model Airflow Pool Sur-
face Area
Moisture
Removal
@50%RH
Moisture
Removal
@60%RH
cfm (L/s) ft2 (m2) lb(kg)/hr lb(kg)/hr
PC-45 1200 (570) 600 (56) 14 (6.4) 18 (8.2)
PC-55 1500 (710) 800 (74) 19 (8.6) 23 (10)
PC-65 1900 (900) 1050 (98) 24 (11) 30 (14)
PC-75 2100 (990) 1200 (110) 28 (13) 33 (15)
PC-80 2400 (1130) 1350 (130) 32 (14) 38 (17)
*Residential application with Tp=80°F and Ta=82°F
EWT=80°F and EAT=82°F
TABLE 3 - Step by Step Pool Evaporation Rate Calculation
Step Action Variable Example Unit
1 Select pool water temperature* Tp 80 °F
2 Select pool room air temperature* Ta 82 °F
3 Select Non-Active Humidity Level (50 or 60%) RHna 50 %
4 Select the number of active hours Ha 2 hours
5 Calculate the number of non-active hours = 24 - Ha Hna 22 hours
6 Lookup the active Evaporation Rate Factor from TABLE 8 ERFa 0.036 lb/hr/ft2
7 Lookup the non-active Evaporation Rate Factor from TABLE 7 or 8 (50 or 60% from Step 3). ERFna 0.048 lb/hr/ft2
8 Select the activity factor (see TABLE 6) AF 0.5
9 Calculate the Average Evaporation Rate Factor = [(Ha x ERFa x AF) + (Hna x ERFna x 0.5)] / 24 ERFavg 0.0235 lb/hr/ft2
10 Select Pool Surface Area Ap 800 ft2
11 Calculate Pool Evaporation Rate = Ap * ERFavg --> match to Moisture Removal in TABLE 4 or 5 ERp 18.8 lb/hr
*It is recommended that the air temperature be 2°F above the pool water temperature. The lower the air temperature in comparison to
the water temperature, the higher the evaporation rate. Typical residential values are Tp = 80°F (27°C) and Ta = 82°F (28°C).
TABLE 5 - PC Typical Sizing (50 Hz)
Model Airflow Pool Sur-
face Area
Moisture
Removal
@50%RH
Moisture
Removal
@60%RH
cfm (L/s) ft2 (m2) lb(kg)/hr lb(kg)/hr
PC-45 1200 (570) 500 (46) 13 (5.9) 15 (6.8)
PC-55 1500 (710) 700 (65) 16 (7.3) 19 (8.6)
PC-65 1900 (900) 900 (84) 20 (9.0) 25 (11)
PC-75 2100 (990) 1000 (93) 23 (11) 28 (13)
PC-80 2400 (1130) 1100 (102) 26 (12) 32 (14)
*Residential application with Tp=80°F and Ta=82°F
EWT=80°F and EAT=82°F
TABLE 6 – Activity Factor (AF)
AF Application
0.5 residential
0.65 therapy, aquafit, elderly swim, fitness club, condominium
0.8 hotel
0.8 school
1.0 public pool, spa, or whirlpool

ISSUE 03: 1-Oct-2021 Page 9 002291MAN-03
TABLE 7 - Evaporation Rate Chart (50% RH) – lb/hr/ft2
Air Temperature (Ta) °F
86 85 84 83 82 81 80 79 78 77 76
Pool
Water
Temp.
(Tp) °F
78 0.034 0.036 0.038 0.038 0.040 0.042 0.044 0.046 0.048 0.050 0.052
80 0.042 0.044 0.046 0.046 0.048* 0.050 0.050 0.052 0.054 0.056 0.058
82 0.048 0.050 0.052 0.052 0.054 0.056 0.058 0.060 0.062 0.064 0.066
84 0.056 0.058 0.060 0.060 0.062 0.064 0.066 0.068 0.070 0.070 0.072
86 0.062 0.066 0.068 0.068 0.070 0.072 0.074 0.076 0.076 0.078 0.080
88 0.072 0.074 0.076 0.076 0.078 0.080 0.082 0.084 0.086 0.086 0.088
90 0.080 0.082 0.084 0.084 0.086 0.088 0.090 0.092 0.094 0.096 0.098
92 0.090 0.092 0.094 0.094 0.096 0.098 0.100 0.100 0.102 0.104 0.106
94 0.098 0.102 0.104 0.104 0.106 0.108 0.108 0.110 0.112 0.114 0.116
96 0.110 0.112 0.114 0.114 0.116 0.118 0.120 0.120 0.122 0.124 0.126
98 0.120 0.122 0.124 0.124 0.126 0.128 0.130 0.132 0.134 0.136 0.138
100 0.132 0.134 0.136 0.136 0.138 0.140 0.142 0.144 0.146 0.148 0.148
102 0.144 0.146 0.148 0.148 0.150 0.152 0.154 0.156 0.158 0.158 0.160
104 0.156 0.158 0.160 0.160 0.162 0.164 0.166 0.168 0.170 0.172 0.174
TABLE 8 - Evaporation Rate Chart (60% RH) – lb/hr/ft2
Air Temperature (Ta) °F
86 85 84 83 82 81 80 79 78 77 76
Pool
Water
Temp.
(Tp) °F
78 0.020 0.022 0.026 0.028 0.030 0.032 0.034 0.036 0.038 0.040 0.042
80 0.026 0.030 0.032 0.034 0.036* 0.038 0.040 0.044 0.046 0.048 0.050
82 0.034 0.036 0.038 0.042 0.044 0.046 0.048 0.050 0.052 0.054 0.056
84 0.040 0.044 0.046 0.048 0.050 0.054 0.056 0.058 0.060 0.062 0.064
86 0.048 0.052 0.054 0.056 0.060 0.060 0.064 0.066 0.068 0.070 0.072
88 0.058 0.060 0.062 0.064 0.066 0.070 0.072 0.074 0.076 0.078 0.080
90 0.066 0.068 0.070 0.074 0.076 0.078 0.080 0.082 0.084 0.086 0.088
92 0.074 0.078 0.080 0.082 0.084 0.088 0.090 0.092 0.094 0.096 0.098
94 0.084 0.088 0.090 0.092 0.094 0.096 0.098 0.100 0.104 0.106 0.108
96 0.094 0.098 0.100 0.102 0.104 0.106 0.110 0.112 0.114 0.116 0.118
98 0.106 0.108 0.112 0.114 0.116 0.118 0.120 0.122 0.124 0.126 0.128
100 0.118 0.120 0.122 0.124 0.128 0.130 0.132 0.134 0.136 0.138 0.140
102 0.130 0.132 0.134 0.136 0.140 0.142 0.144 0.146 0.148 0.150 0.152
104 0.142 0.144 0.146 0.150 0.152 0.154 0.156 0.158 0.160 0.162 0.164
3) Airflow across pool surface: Increased airflow across
the surface area of the pool increases the evaporation rate.
Ducting should de designed to minimize the airflow across
the pool to reduce this effect. See the Ductwork section for
more information.
4) Room air temperature: As mentioned in (1), the pool room
temperature is normally kept slightly above the water
temperature to minimize the amount of evaporation taking
place.
5) Room relative humidity: The relative humidity setpoint for
most pool areas is from 50% to 60%. Lowering the relative
humidity setpoint will increase the evaporation rate from the
pool thus causing the pool conditioner to run more, but may
be necessary to prevent condensation on some glass
surfaces during cold weather. Relative humidity should be
set only low enough to prevent condensation from occurring
on windows and doors.
TABLE 3 gives a step by step explanation of how to
determine the evaporation rate of the pool. Once the Pool
Evaporation Rate (ERp) has been calculated then it can be
matched to the moisture removal for a particular PC model size
in TABLE 4 or 5 (looking in the 50% or 60% columns according
to selected RHna).
TABLE 4 or 5 also gives a general idea as to the size of
pool that can be accommodated by each model size for a typical
residential installation. This is just a guideline; the Pool Evapo-
ration Rate (ERp) should be calculated as per TABLE 3.
Plenum Heater Sizing
Plenum heaters are available as accessories in 5, 7, 10,
15 and 20kW sizes. Choose a size that matches a heat load
calculation for the pool room, or if that is not available, use the
following recommendation:
TABLE 9 - Plenum Heater Sizing
MODEL kW
PC-45, 55 15
PC-65, 75, 80 20
* value for
recommend-
ed setpoints
* value for
recommend-
ed setpoints

ISSUE 03: 1-Oct-2021 Page 10 002291MAN-03
Installation Basics
Unpacking the Unit
When the equipment reaches its destination it should be
unpacked to determine if any damage has occurred during
shipment. Any visible damage should be noted on the carrier's
freight bill and a suitable claim filed at once.
PC Indoor Unit Placement
Some thought as to how the unit is placed will make air
ductwork and piping connections much simpler. See diagram
002297PDG later in this manual for an example placement.
The front access panels should remain clear of obstruction
for a distance of two feet to facilitate servicing and general
maintenance. No access is required on the back side. Ensure
the unit is level to eliminate any possible condensate draining
issues.
Raising the unit off the floor, as shown in the diagram, can
make connections easier. Room for the condensate to drain
under gravity, either to the pool or to a condensate pump,
must be provided; and condensate drain connections are at
the bottom of the unit. An anti-vibration pad, available as an
accessory, or a piece of 2” styrofoam should be placed under
the unit. Be careful not to run piping in front of the filter rack
access cover, since access is required in order to change the air
filter.
The PC unit is available in top, side/end, and bottom air
discharge configurations from the factory; be sure to plan duct-
work and order the most appropriate configuration. It is sug-
gested that supply ductwork be kept low, and air return grill high
for most effective and efficient operation. See the Ductwork
section later in this manual for details.
Normally, water will be circulated continuously through the
pool conditioner by the pool filter pump. A bypass should be
installed as described later in this manual, to allow adjustment of
flow through the PC unit for optimum refrigerant head pressure
and highest efficiency. The PC unit can control the pool pump if
required.
WARNING: Pool chemicals should be stored
in a different room from the PC unit to pre-
vent premature corrosion problems.
WARNING: Pool chemicals should be inject-
ed downstream of the PC unit.
Sample Bill of Materials
Although not exhaustive, following is a list of materials needed
for a typical installation:
FROM MARITIME GEOTHERMAL
• PC-SERIES POOL CONDITIONER
• COMMUNICATING ROOM THERMOSTAT (REQUIRED)
• TWISTED-PAIR THERMOSTAT WIRE (REQUIRED)
• ELECTRIC PLENUM HEATER
• AC2-SERIES OUTDOOR CONDENSER (OPTIONAL)
OPTIONAL FROM MARITIME GEOTHERMAL
• ANTI-VIBRATION PAD
• COMPRESSOR SOUND JACKET
• COMPRESSOR SECURE START
DUCTWORK
• OUTLET PLENUM ADAPTER W/ FLEXIBLE COLLAR
• RETURN AIR ADAPTER W/ FLEXIBLE COLLAR
• FIBREGLASS INSULATION (FOR NOISE, IF REQ’D)
• TRUNK DUCT W/ JOINERS (IF NOT EXISTING)
• 6” ROUND DUCT W/ADAPTERS (IF NOT EXISTING)
• ALUMINUM TAPE
• SHEET METAL SCREWS
POOL PIPING
• POOL PUMP & FILTER
• 2” PVC PIPE & FITTINGS & GLUE
• 2” PVC BALL VALVES (2)
• CONDENSATE TRAP ASSEMBLY & DRAIN PIPING
• CONDENSATE PUMP (IF REQ’D)
REFRIGERATION (FOR OPTIONAL AC2 UNIT ONLY)
• 1/2” ACR TUBING
• PIPE ISULATION
• EXTRA R410A REFRIGERANT FOR LINESETS >20 FT
ELECTRICAL
• ELEC. SERVICE WIRE OF CORRECT SIZE
• BREAKER FOR PC UNIT
• PLENUM HEATER SERVICE WIRE
• PLENUM HEATER BREAKER
• WIRE 14-2 (OUTDOOR) FOR OPTIONAL AC2 UNIT
• OUTDOOR DISCONNECT SWITCH FOR AC2 UNIT
• THERMOSTAT WIRE 18-2
• THERMOSTAT WIRE 18-3
• THERMOSTAT WIRE 18-3 (OUTDOOR)
• FORK TERMINALS FOR TSTAT WIRE (6)
• TRANSFORMER, CONTACTOR, EXT. ELEC. BOX IF
POOL PUMP TO BE CONTROLLED BY PC UNIT
• 2” STYROFOAM INSUL. (IF PAD NOT PURCHASED)

ISSUE 03: 1-Oct-2021 Page 11 002291MAN-03
Optional AC2 Outdoor Unit Placement
The optional AC2 unit must be placed outdoors, with the
fan pointing away from the building. It should be at least 12
inches (30 cm) away from the building or other obstructions
on the back and sides for unimpeded return airflow. There
should be little or no obstruction in the fan (front) direction for at
least 30 feet (9 m), otherwise airflow and therefore overall per-
formance will be reduced.
In addition, there should be at least two feet (0.6 m) of
clearance on the electrical box and refrigeration piping side of
the unit to facilitate servicing and general maintenance.
If there is any expectation that heat rejection (air cooling)
mode will be required while there is snow on the ground, the
outdoor unit must be mounted high enough so that it remains
clear of snow and ice at all times. Since this is not likely, the
unit may be mounted at ground level in most cases. If required,
two different leg kits which add either 15” (38 cm) or 30” (76 cm)
of additional height are available as an accessories.
The AC2 must be bolted down to prevent a tipping hazard.
Note that no field installed filter-dryer is required, since
one is included in the indoor unit.
IMPORTANT NOTE: The line set between the
indoor and outdoor units must not exceed 70
ft (21 m) in length.
Outdoor Unit
Fan Orientation
Outdoor Fan Speed Reduction
Should fan noise be a concern, for example if the outdoor
unit is mounted near a frequently open window, the outdoor fan
speed can be reduced (up to a maximum of 25%). This should
only be done if necessary, since a small loss in efficiency will
result.
The fan speed can be reduced via the LCD (see LCD In-
terface & Menus section) or PC App (see PC Application
section).

ISSUE 03: 1-Oct-2021 Page 12 002291MAN-03
Wiring
TABLE 10 - PC-Series Power Supply Connections
Line Description Voltages
L1 Line 1 All
L2 Line 2 All
L3 Line 3 3-phase only
N Neutral 460-3-60, 380-3-50 only
GND Ground All (connect to ground lug)
PC-Series Power Supply Connections
The unit has a concentric 1.093” / 0.875” knockout for pow-
er supply connection to the electrical box. There are also two
7/8” knockouts and a 1/2” opening with plastic grommet
(grommet hole is 3/8”) for connections to the supplied air ther-
mostat, optional external pool water aquastat, and power and
signal connections to optional outdoor condensing unit.
A schematic diagram (SCH) and electrical box layout
diagram (ELB) can be found on the electrical box cover of the
unit as well as in the Model Specific Information section of this
manual.
The Electrical Tables in the Model Specific Information
section contain information about the size of wire for the con-
nections, as well as the recommended breaker size.
Pool Pump Signal Connections
In most installations, the pool pump will be always on, to
constantly circulate pool water through the filter. So there will
always be pool water circulation through the PC unit, with no
controls required.
However, the PC unit does have a dry contact to relay an
external 24VAC signal to activate the pool pump contactor when
the PC requires pool water flow; that is, in pool water heating
mode. The 24VAC transformer and contactor will be contained
in an external electrical box. See the following wiring connec-
tion diagram 002298CDG.
Connect the 24VAC signal to be relayed to terminals CP1
and CP2 on the PC unit’s terminal strip with an 18-2 cable.
TABLE 13 - Pool Pump Signal Connections
Signal Description
CP1
CP2
Use a 2-conductor 18ga cable.
Dry contacts for pool pump contactor
TABLE 11 - AC2-Series Power Supply Connections
Line Description
L1 Supply line
L2 Supply line
GND Ground
Use a two conductor outdoor rated 14ga minimum cable.
Optional AC2-Series Outdoor Unit:
Power Supply Connections
The AC2 outdoor unit is powered from the PC unit. The
power supply for the AC2 unit is 208 to 277VAC, 50/60Hz. The
PC and AC2 units have matching terminal strips for these con-
nections. Use a two conductor, minimum 14ga outdoor rated
cable for this connection. Refer to diagram 002298CDG.
Auxiliary Plenum Heater:
Signal Connections
The PC unit has two dry contacts to control the 2 stages of
the plenum heater. These dry contacts can also be used to
control other types of auxiliary air heat. Note that dry contacts
are intended to activate equipment that has its own 24VAC
transformer; if equipment does not have its own transformer,
one will need to be installed in an external electrical box.
Connect the terminals on the PC’s terminal strip to the
matching terminals on the plenum heater’s control board using
an 18-3 cable.
TABLE 12 - Plenum Heater Signal Connections
Signal Description
CP Common
1
2
Use a 3-conductor 18ga cable.
Dry contact for auxiliary heat stage 1
Dry contact for auxiliary heat stage 2
Auxiliary Plenum Heater:
Power Supply Connections
Auxiliary heat for the pool room air will usually be provided
by an electric duct heater (plenum heater). These are available
as accessories in 5, 7, 10, 15, and 20 kW sizes, and are in-
stalled in the air discharge ductwork outside the PC unit. The
plenum heater will have its own breaker and power supply wire.
The Electrical Tables in the Model Specific Information section
contain information about the size of wire for the connections, as
well as the recommended breaker size.
IMPORTANT NOTE: Most codes require a
disconnect switch visible and/or reachable
from the outdoor unit to be installed in the
power supply cable. If the switch has fuses
or breakers they must be no more than 10A.
OUTDOOR DISCONNECT SWITCH IS A
SAFETY DEVICE ONLY. Turn off breaker to
indoor unit before servicing to avoid costly
damage to electronic control board.
NOTE: A properly qualified electrician
should be retained for all connections to the
heat pump and associated controls.
IMPORTANT NOTE FOR 3-PHASE UNITS: If
on startup compressor is noisy and not
pumping, reverse L1 and L2 supply wires.

ISSUE 03: 1-Oct-2021 Page 13 002291MAN-03
TABLE 15 - Outdoor Unit Signal Connections
Signal Description
PWM+ Outdoor Fan Control
DET
DET
Use the included shielded 8-conductor outdoor rated 18ga
cable.
Auto-detection of AC2 unit
Optional AC2-Series Outdoor Unit:
Signal Connections
The speed of the fan in the optional AC2 outdoor unit is
controlled by the control board in the indoor PC unit. In addition,
the PC has an auto-detect function for the outdoor unit, so that
no settings need to changed if installing the optional AC2
(enabling heat rejection/air cooling mode). Therefore, communi-
cation wiring is required.
The PC and AC2 units have matching terminal strip sig-
nals for these connections. Connections are labeled PWM+,
DET, and DET (the two DET terminals being interchangeable).
Use 3 conductors of the included 18-8 shielded outdoor rated
cable for this connection. If longer than 50 ft is required, inform
when ordering unit. Refer to diagram 002298CDG.
TABLE 14 - Control Transformer
Voltage Low Voltage Circuit Protection
(1) 208/230-1-60 Resettable breaker on transformer
(2) 208-3-60 Resettable breaker on transformer
(4) 460-3-60 Primary / Secondary fuses
(6) 220-1-50 Primary / Secondary fuses
(7) 380-3-50 Primary / Secondary fuses
IMPORTANT NOTE: For 208/230VAC-1-60
units, if connecting to 208VAC power supply
move the red wire connected to the 240 ter-
minal of the transformer to the 208 terminal
of the transformer.
Control Transformer
The rest of the low voltage controls, including the control
board, are powered by a 100VA class II transformer. 208/230-1
-60 and 208-3-60 models have a resettable breaker on the sec-
ondary side for circuit protection. Should the breaker trip, locate
and correct the problem and then reset the breaker by pressing
in on it.
All other voltage models have primary and secondary fus-
es for circuit protection.
Air Thermostat Connections
The pool conditioner unit comes with its required air ther-
mostat, which is the BAPI Stat4 (model BA/BS4MBC-G-H2-FN-
Z or close variation). This is both a communicating room
sensor for air temperature and humidity, and also a user inter-
face to change the air temperature and humidity setpoints. It
communicates with the PC unit via the MODBUS protocol on an
RS485 bus using a twisted wire pair. There are also two power
wires required, so the thermostat should be connected using a
double-twisted-pair wire. 50 ft of this wire is supplied along with
the thermostat; be sure to order a longer wire if required.
Connect the terminals at the lower right of the PC’s control
board to the BAPI Stat4 as follows. Also see connection dia-
gram 002298CDG following, and PC wiring (SCH) diagrams in
the Model Specific Information section or on the electrical box
cover.
TABLE 16 - Air Thermostat Connections
PC
board
BAPI
Stat4 Wire Description
A NET A TWISTED
PAIR 1 Communication +
B NET B Communication -
24VDC POWER TWISTED
PAIR 2
24VDC power
GND GND ground
Use the included double twisted pair cable.
Accessory Connections
In most installations, accessories that are not already de-
scribed will not be required. Other available accessories in-
clude:
 External pool water temperature sensor, replacing the inter-
nal water OUT line temperature sensor for use with the PC
control board’s Setpoint Control routine. This is called HTS/
CTS Setpoint Control, described later.
 External aquastat, to control pool water heating demand,
replacing the PC’s Setpoint Control routine.
 Compressor current sensor.
 External dry contact to reduce air flow by the AR percent
factor
See the PC wiring (SCH) diagrams in the Model Specific
Information section or on the electrical box cover for these
connections.
Disable Switch (field installed)
A switch to disable demand from the control system may
be installed. On control board, jumper COM_IN to GND, and
toggle 12VDC to IN_SPARE to disable. See the main wiring
diagram in the Model Specific Information section.
Air Conditioning with Cold Water
Normally, installations that require air cooling will use the
accessory outdoor unit to reject heat to the outdoor air. Howev-
er, for locations that have well water or other cold water availa-
ble and a place to reject the water to, like a drain or return well,
this is an alternative to using the outdoor unit. See Piping chap-
ter for details.

ISSUE 03: 1-Oct-2021 Page 14 002291MAN-03

ISSUE 03: 1-Oct-2021 Page 15 002291MAN-03
Pool Water Lines
The connections for the pool loop are 2” PVC unions,
rigidly fixed to the cabinet to prevent relative movement
and possible resulting damage to interior piping. They are
labelled as INDOOR IN and INDOOR OUT.
Piping for a typical system is shown in following diagram
002297PDG . This diagram shows all of the recommended
components as well as where they should be placed, although
placement will vary according to layout of duct system and
space in mechanical room. The unions allow access to the co-
axial heat exchanger should it require cleaning, and quick dis-
connect of PC unit.
NOTE: Care should be taken when routing the water lines to
ensure that adequate access to the heat pump is maintained so
as to not compromise ease of serviceability, particularly access
to both side doors and the air filter change cover.
Drawing 002297PDG following also outlines the method
for setting the water flow based on refrigerant head pressure,
using two hand-operated ball valves. It is important to follow
this procedure to ensure high efficiency operation and long ser-
vice life for equipment, and to avoid service calls due to nui-
sance safety control trips.
Condensate Drain
The unit comes equipped with two 3/4” female NPT drain
connections, labeled “Condensate Drain”. This drain allows the
condensate which forms during the air-conditioning cycle to be
removed from the unit. The drain should be connected as per
local codes. During high humidity weather, there could be as
much as 25 gallons of water formed per day.
The condensate drain requires an external trap. It is rec-
ommended to use a pre-made trap with cleanout like that shown
in the diagram. The drain should be back to the pool where
allowed by codes, in order to reduce the amount of make-up
water required for the pool. An external condensate pump may
be installed if there is not sufficient slope to drain condensate
under gravity to its destination.
NOTE: The condensate drain operates by gravity. Ensure
the unit is mounted high enough to allow the condensate to
flow without overflowing the internal drip tray located at the
bottom of the unit.
To avoid overflow of the condensate pan, the drain line
and trap should be inspected periodically to ensure they are not
plugged with accumulated debris.
Piping
Simultaneous Pool/Hot Tub Heating
The following diagram 001824PDG shows two suggested
methods of heating both a pool and a hot tub with the PC unit.
Note that if heating two pools of differing temperatures
using a parallel arrangement as in section 1 of the diagram,
external aquastat(s) will be needed to control the pool water
heating demand, since the internal Setpoint Control routine only
has one setpoint. Also, the flow will need to be set using the
procedure outlined on diagram 002297PDG, but flow through
the pool and hot tub will need to be set separately because of
the different water temperatures.
If using an indirect pool heating arrangement as shown in
section 2, the internal Setpoint Control routine can be used.
Alternatively, the PC unit can be used to heat the pool,
while the hot tub can be heated by a different pool heating de-
vice dedicated for that purpose.
Air Conditioning with Cold Water
Normally, installations that require air cooling will use the
accessory outdoor unit to reject heat to the outdoor air. Howev-
er, for locations that have well water or other cold water availa-
ble and a place to reject the water to, like a drain or return well,
there is an alternative to using the outdoor unit.
A pair of 24VAC 3-way valves can be placed in the IN and
OUT pool water lines connected to the unit, as shown in the
diagram on following page. Connect the IN valve common port
to the PC IN port, the NO port to the supply from the pool, and
the NC port to a clean cold water source. It may also be neces-
sary to install a regulating valve (e.g. hand valve, dole valve) to
restrict the flow to obtain the recommended discharge pressure
of 350-400PSIG. Connect the OUT valve common port to the
PC OUT port, the NO port to the return line to the pool, and the
NC port to a suitable drain.
The valves can be controlled by the L1 output from the
PC’s control board, as shown. L1 will output 24VAC whenever
the PC unit enters air cooling mode. Note the current limit of
500mA from L1; if 3-way valve current draw exceeds 500mA,
or if 3 way valves with non-24VAC coils are used, a separate
power supply switched by a 24VAC relay is required.
In the absence of an outdoor unit, a jumper from DET-DET
is required to enable air cooling mode, as shown on diagram.

ISSUE 03: 1-Oct-2021 Page 16 002291MAN-03

ISSUE 03: 1-Oct-2021 Page 17 002291MAN-03

ISSUE 03: 1-Oct-2021 Page 18 002291MAN-03

ISSUE 03: 1-Oct-2021 Page 19 002291MAN-03
Duct Systems - General
The duct system should be constructed of standard galva-
nized sheet metal, such as would be used for a typical residen-
tial heating system. All joints should be sealed with an ap-
proved duct sealant to ensure there are no leaks in the system.
A duct system capable of supplying the required air flow is
of utmost importance. Maritime Geothermal Ltd. recommends
that the static pressure be kept below 0.2 inches of water total.
It is VERY IMPORTANT that all turns in both the supply
trunks and the return trunks be made with TURNING RADII. Air
acts like a fluid and, just like water, pressure drop is increased
when air is forced to change direction rapidly around a sharp or
irregular corner.
It is recommended that flexible collars be used to connect
the main trunks to the heat pump. This helps prevent any vibra-
tions from travelling down the ductwork.
The first 5-10 feet of the main supply trunks may be insu-
lated with acoustical duct insulation to further inhibit any noise
from the unit from travelling down the ductwork.
Supply Duct System
The care and attention devoted to setting up the air
distribution system can make or break any indoor pool
conditioning system. Important factors to consider are:
1) Sufficient air must be moved within the pool enclosure to
satisfy the requirements of both the occupants of the room
and the pool conditioner, with maximum flow directed over
the outside windows and doors and minimum flow directly
over the exposed surface of the pool itself.
2) To prevent air stagnation and stratification the system must
provide at least 4 to 8 room air changes per hour.
3) The PC unit supply air ductwork must be adequately sized
to handle 1200 to 2400 cfm of air (depending on the model
size) with no more than 0.20” H2O of external static
pressure. See following table for a duct sizing guide that
can be used to select adequate duct sizes.
4) An in-floor duct system is usually the most effective method
of supplying air to the room (see following diagram).
Distribution of the conditioned air will be most effective if the
air is released from the floor and allowed to rise upwards
over the glass surfaces. It is important to try and blanket the
entire surface of glass windows and metal doors with a film
of dry air from the pool conditioner to prevent accumulation
of condensation at the corners or bottom of the glass. If a
ceiling ducted system is chosen, then the supply air should
be of sufficient velocity to ensure that air flows over the
glass all the way down to the bottom of the window.
5) Long, narrow supply grills should be placed under all glass
areas exposed to outside temperatures for optimum
operation.
6) Additional care should be taken to ensure that airflow is not
directed across the pool surface since moisture loss from
the pool water will be greatly increased under these
conditions.
7) If a floor distribution system is not possible then ceiling
ducts should be positioned to blow down over the exposed
glassed areas of the room perimeter. It may be necessary
to increase the airflow using the PC App to accomplish the
more difficult task of forcing the air exiting the supply ducts
down over the glass.
Return Duct System
The air inlet of the return duct system should ideally be
placed 10 to 15 ft above the pool level. Placing this duct inlet in
an elevated position will ensure that air travels in an upward
fashion if it is introduced from the floor. An airflow pattern which
causes minimum airflow across the pool surface should be used
to minimize evaporation from the pool surface. Large volumes
of air travelling near the pool surface can also cause swimmers
to feel cold whenever they emerge from the water.
Plenum Heater
As mentioned in previous sections, it is recommended that
a plenum heater be installed to provide pool room air auxiliary
heat.
The plenum heater should be mounted in the supply duct
in a manner that allows all or most of the airflow to pass through
it to prevent any hot spots in the heater elements. If the ele-
ments overheat due to experiencing low airflow, they will shut
down on thermal overload controls in the plenum heater, and
sporadic operation resulting in low heat output will occur.
The plenum heater should be placed downstream of the
flex collar as shown in diagram 002297PDG, or at least 12”
away from the flex collar if placed upstream. Duct insulation
should not be placed within 12” of the heater elements.
Ductwork

ISSUE 03: 1-Oct-2021 Page 20 002291MAN-03
The diagram above shows another possible technique for installing supply ducts in the pool room. Dry air is directed downward over the windows
A, B, C and D. As the air picks up moisture from the pool room it is drawn towards the return air grill E where it re-enters the pool conditioner.
In each case air is released over the glass and drawn to the return air grill of the PC with as little travel as possible over the pool surface.
The diagram above shows a common technique for installing supply ducts in the pool room. Dry air is directed upward over the windows A, B, C
and D. As the air picks up moisture from the pool room, it is drawn towards the return air grill E where it re-enters the pool conditioner. Air is released
over the glass and drawn to the return air grill of the PC with as little travel as possible over the pool surface.
Supply ducts “F” are located below the concrete pool decking and insulated with waterproof closed cell or styrofoam insulation so that the air at
each supply grill is at approximately the same temperature.
Floor diffusers “G” should be placed close to the windows and be wide enough to direct air over the entire glass surface to ensure that no
condensation occurs in corners or on the lower levels of the glass.
FIGURE 1 - Floor Supply Ducts With Elevated Return
B
A C
D
E
Mechanical Room
F F
15’
G
FIGURE 2 - Elevated Supply Ducts With Elevated Return
B
A C
D
E
Supply air Supply air