Calorex DIGITAL LOGIC AT800 Quick start guide

MEMBER
Pool
Heat
Pump
Manufacturers
Association
MEMBER
OWNERS
OPERATIONAL MANUAL
SWIMMING POOL & SPA
HEAT PUMPS
WARNING: Specifications may change without notice.
NATIONAL
POOL & SPA
INSTITUTE
V2.3-AT © 2001 Calorex U.S.A. LLC
SWIMMING POOL & SPA
HEAT PUMPS
NOTE: Installers should see separate installation manual !
Model AT800 AT600 & AT400
“BLACK CABINET” with DIGITAL CONTROLDIGITAL CONTROL
DIGITAL CONTROLDIGITAL CONTROL
DIGITAL CONTROLSS
SS
S ONLY ONLY
ONLY ONLY
ONLY
DIGITAL LOGIC™DIGITAL LOGIC™
DIGITAL LOGIC™DIGITAL LOGIC™
DIGITAL LOGIC™

A. Introduction ..............................................................................
1. Unit Exterior Description
2. How Does A Heat Pump Work
B. Heat Pump Description ............................................................
1. Control Panel Description
2. Optional Time Clcok Override Description
3. LED Display & Status Light Descriptions
C. Operational Instructions ...........................................................
1. Water Flow & Water Pump Timer Setting
2. Thermostat Setting
3. Optional Time Clock Override Setting
4. Time Delay Modes
5. Normal Operation Indicators
6. Pool/Spa Covers (Blanket) Use
7. Spa Heating Suggestions
8. Defrost Mode Control
D. Owner Required Maintenance & Precautions ........................
1. Air Flow & Service Clearances
2. Chemicals, Feeders & Water Balance
3. Owner Cleaning & Maintenance
4. Professional Service Requirements
5. Warranty Service Requirements & Notes
6. Operational Sequence & Troubleshooting Flow Chart
Pages 2 - 3
Pages 4 - 5
Pages 6 - 7
Page 8 - 12
Written & Illustrated by Michael Glore
Table of Contents
Introduction
Congratulations on the purchase of your new pool/spa heat pump. A Heat Pump is one of the
most efficient ways to heat your pool or spa. Your heat pump was manufactured by Calorex
USA, the very first company to produce swimming pool heat pumps. Since making the very first
pool heat pump some 24 years ago, Calorex has become the industry leader in reliability and
efficiency.
You can expect to get more use from your pool or spa investment with your new heat pump.
The heat pump will extend your swimming season at very affordable operational cost. When
compared to propane gas pool/spa heaters, the heat pump is 5 times more efficient. The heat
pump is pollution free & environmentally friendly.
Please review this owners manual so you can better understand the use and operation of your
new heat pump. Be advised there is a separate installation manual shipped with each heat pump.
Important Information to Record
Installer Name
Installer Phone Install Date
Model Number Serial Number
5826 Corporation Circle Ft. Myers Florida 33905
U.S.A. L.L.C.
888-297-3826 www.calorexusa.com [email protected]
NOTICE
Technicians See Separate “Installation Manual”. Specifications may change without notice.

Page 3
Unit Description AIR DISCHARGE FAN
WARNING: ROTATING BLADE KEEP
HANDS & HAIR CLEAR!
THERMOSTAT
CONTROLS
POOL/SPA
LED READOUT
WATER OUT
PIPE
REFRIGERANT
SERVICE VALVES
DO NOT OPEN !
WATER IN
PIPE
SERIAL
NUMBER
PLATE
“OPTIONAL”
TIME CLOCK
OVERRIDE
SWITCH
ELECTRICAL
SUPPLY WIRING
ACCESS PANEL
“KEEP OUT”
ELECTRICAL
INSTALLATION
PORTS
POOL/SPA
SELECT SWITCH
DANGER FROM ELECTRICAL
SHOCK & ROTATING FAN !
SHUT OFF ALL POWER
BEFORE SERVICING !
CAUTION: MORE THAN ONE
DISCONNECTION MAY BE
REQUIRED TO ELIMINATE ALL
POWER TO THIS UNIT INCLUDING
POWER TO THE OPTIONAL TIME
CLOCK OVERRIDE !
WARNING
A swimming pool & spa pump utilizes proven refrigerant technology to capture the heat in the
outside air and transfers it to the pool water. Refrigerant is used because of its ability to absorb and
transfer heat energy. The fan circulates air through the outer evaporator air coil that acts as a heat
collector. The liquid refrigerant in the air coil absorbs the
available heat in the ambient air, transforming it into a
gas. The refrigerant gas is then
pumped into the compressor.
When this warmed gas is com-
pressed, it intensifies or concen-
trates the heat, like a magnifying
glass in the sun.
This intensely hot gas is then
pumped into the heat ex-
changer condenser, where the
actual heat transfer takes place.
As the pool water passes
through the heat exchanger, the
hot gas gives up its heat to the cooler pool wa-
ter. The refrigerant returns to a liquid state and
is pumped through the expansion valve then
into the evaporator air coil to start the process all
over again.
How Does A Heat Pump Warm My Pool ?
How Efficient Is It ?
This graph is a operational cost comparison for equal
amounts of pool heat. As you can see heat pump is
the most efficient way to heat your pool.
Compared to L.P. gas heaters, a heat pump produces
5 to 6 times more heat for every $1.00 you spend
on operation.
FAN
WARM
AIR
COOL
AIR
COMPRESSOR
POOL
WATER
PUMP
FILTER
HEAT EXCHANGER
CONDENSER
EXPANSION
VALVE
EVAPORATOR
AIR COIL
WARMED
GAS
OFF/ON
SWITCH

HEATER ON/OFF:
To start the heater press this button and it’s green light will come on. To disable the
heater press this button and its green light will go off.
THERMOSTAT BUTTONS:
Pressing the + button will raise the set temperature. Pressing the - button will lower the
set temperature. When either button is pressed the LED display will begin to flash. The
flashing numbers indicate the thermostat setting.
MODE SELECT BUTTONS-POOL or SPA: The heater has two thermostat modes for
two different desired temperature settings, one for pool mode and one for spa mode.
If you do not have a spa use the pool mode only. If you do have a spa, you can connect
two Jandy™ motorized plumbing valves. Therefore, when you select either mode the
motorized valves will turn to isolate the heater to either the pool or spa. NOTE: There
is a 30 second compressor when switching pool/spa modes.
“OPTIONAL” WATER PUMP TIME CLOCK OVERRIDE OPERATION When the T.C.O. but-
ton is set to the ON mode, the Time Clock Override feature is designed to start the
water pump whenever the pool requires heat. Once the pool is up to the set tempera-
ture the heater will stop and then 5 minuets later the water pump will stop. When this
button is set to the OFF mode, the heater will operate only when the water pump is
running during the timed period set on the water pumps time clock.
NOTE: The time clock override works best if used during cooler weather conditions
where the pool is loosing more than 8 to 10 degrees over night or when the pool is
being heated from “dead cold”.
NOTE: If the time clock override starts the water pump and the thermostat does not
continue to call for heat for at least 5 minuets, the control will shut the water pump and
heater off. Thereafter, it will not re-attempt to start the water pump for 4 hours. This 4
hour delay can be bypassed by pressing the T.C.O. button off then back on.
NOTE: When the T.C.O. button is activated while in “spa mode” the water pump will
run the entire time you are in sap mode. When you switch back to pool mode there will
be a 5 minute delay before the water pump shuts off. The T.C.O. option is built into the
heater at the factory and can not be added later.
Page 4
“Digital Logic” Digital Control Panel Information

GREEN POWER LIGHT: This light indicates that the heater has control power.
WARNING: This is not a supply line power indicator and caution should be used since
more than one power disconnection may be required to isolate the heater electrically.
WARNING: If the optional Time Clock Override is installed, you must shut off the water
pumps main power disconnect as well to eliminate all power to the heater.
GREEN HEATING LIGHT: This light indicates that the unit is heating and the compres-
sor is running. The compressor starts after a 3 to 5 minute time delay. NOTE: The water
pump must be running at the same time in order for the heater to run.
LED READOUTS:
When the unit has power, the LED will display the current water temperature. When
pressing the thermostat buttons the flashing readout will indicate the set temperature.
The following are LED code readouts for the internal sefety controls that regulate the
unit for various reasons.
LF = LOW WATER FLOWLF = LOW WATER FLOW
LF = LOW WATER FLOWLF = LOW WATER FLOW
LF = LOW WATER FLOW
This light indicates there is no water flow through the heater. The heater is designed to
shut off whenever the water pump is not pumping water through the heater. If LFLF
LFLF
LF is on
while the water pump is running, the water pump may not be supplying enough flow
for the heater to operate properly. During normal operation the heater turns off and on
with the water pump.
dd
dd
dF = DEFROST MODEF = DEFROST MODE
F = DEFROST MODEF = DEFROST MODE
F = DEFROST MODE
This readout indicates that the internal defrost safety control has disabled the heater.
During cold weather where the air temperature drops below approximately 45 to 50
degrees (depending on humidity), the low refrigerant pressure switch (or defrost con-
trol) is designed to disable the compressor only. Once the unit is in defrost mode the
compressor will shut off for 1 hour while the fan continues to help deice and warm the
air coil. After 1 hour the unit will attempt to restart. If the air temperature has increased
to the operational range the compressor will continue to run, otherwise the compressor
will return to the defrost mode for another 1 hour delay cycle.
HP = HIGH REFRIGERANT PRESSURE SHUT OFFHP = HIGH REFRIGERANT PRESSURE SHUT OFF
HP = HIGH REFRIGERANT PRESSURE SHUT OFFHP = HIGH REFRIGERANT PRESSURE SHUT OFF
HP = HIGH REFRIGERANT PRESSURE SHUT OFF
This readout out indicates high refrigerant pressure. The high refrigerant pressure switch
is designed to shut the compressor and fan off if a heat buildup occurs for whatever reason.
Typically, the high refrigerant pressure switch will trip if the water flow through the heater is
restricted. It may also trip if the air flow is restricted through the heater.
Page 5
TIME DELAYS:
30 second compressor delay when switching pool/spa modes.
5 minute compressor delay when T.C.O. enables in pool mode.
5 minute T.C.O. off delay when: switching from spa to pool mode, when temperature is
reached in pool mode, or if LF (low water flow) is displayed on LED.
If water pump loses prime there will be a 3 minute compressor delay.

When heating the pool or spa you should check the following items as they are all
critical to the proper operation of the heater.
1. WATER FLOW
Make sure all pool filters and traps are clean since the unit requires a minimum water
flow in order to operate properly. The heater should and will not run unless the water
pump is running. There is an internal water pressure switch that disables the heater
whenever the water pump is not supplying water flow.
2. WATER PUMP TIMER SETTING
Since the heat pump collects heat from the outside air, you want to set the water pump
timer to run during the hottest part of the day. If you are heating the pool from “dead
cold” you may need to set the water pump timer to run 24 hours until the pool reaches
temperature, then reset the timer for a normal run time. Run times are determined by
pool size, set pool/spa temperature and weather conditions.
3. THERMOSTAT SETTING & MODE SELECT BUTTONS
The LED display will show a constant readout of the actual cur-
rent water temperature. To set the desired water temperature
press either the + or - thermostat buttons. While adjusting the
set temperature, the LED will flash. The flashing numbers will
indicate the thermostat setting.
If you have a spa you can press the spa mode button and set the desired spa tempera-
ture. If you do not have a spa use the pool mode only.
4. OPTIONAL TIME CLOCK OVERRIDE SWITCH
The optional “Time Clock Override” control you can set the switch turn this switch ON
and the heater will start the water filter pump automatically whenever the water tem-
perature drops below the thermostat setting.
This option is best used when heating the pool from “dead cold” and
for maintaining water temperatures during non timed periods where
the pool is losing 8 to 10 degrees or more overnight. The heating
mode select switch is best left in the OFF position during the warmer
parts of the swimming season. The optional time clock override feature is built into the
heater at the factory and can not be added later. See the bottom of page 4 also.
Operational Instructions
Page 6

5. TIME DELAY MODE
This heater is equipped with an internal compressor time delay to allow the refrigerant to
settle during start-up or restart cycles. When the heater is started the fan will run but the
compressor will not start until the 3 to 5 minute delay has passed. The green heating light
will be on when the compressor is running. In some cases (when the heater is new or
during cold weather), it may be necessary to allow the unit to go through the time delay
several times before the unit will start. The unit will delay for other reasons noted below:
TIME DELAYS:
30 second compressor delay when switching pool/spa modes.
3 to 5 minute compressor delay when T.C.O. enables in pool mode.
5 minute T.C.O. off delay when: switching from spa to pool mode, when temperature is
reached in pool mode, or if LF (low water flow) is displayed on LED.
If water pump loses prime there will be a 3-5 minute compressor delay.
6. NORMAL OPERATION INDICATORS
When the fan and compressor are running, the unit will discharge cool air from the top. The
heater will produce condensation while running and is considered normal. It will produce more
condensation the more humid the ambient air is. The condensation will exit the heater through
the bottom drain ports.
7. POOL/SPA COVER USE
You can substantially reduce the heat loss and electrical consumption by utilizing a pool cover
(or pool blanket). You can get higher water temperatures in less operational time using a cover.
If you keep the pool or spa covered whenever you are not swimming you can typically reduce
heat loss by as much as 80% and reduce heating costs as much as 50%. Using a cover during the
initial heat up period will greatly reduce the operational time needed.
8. SPA HEATING
When heating a spa it is advisable to not run the air blower or air inlet venturis during the initial
heat up time. Air blowers and venturis inject air into the water to create the spa therapy action.
During colder weather the air blower or inlet venturis will inject cold air into the spa thus increas-
ing heat demand. Leaving these items off until the spa reaches the set temperature will reduce
the heat up time. A cover is highly suggested for spa heating.
9. DEFROST CONTROL IN COLD WEATHER
dd
dd
dFF
FF
FThis readout indicates that the internal defrost safety control has disabled the heater.
During cold weather where the air temperature drops below approximately 45 to 50
degrees (depending on humidity), the low refrigerant pressure switch (or defrost con-
trol) is designed to disable the compressor only. Once the unit is in defrost mode the
compressor will shut off for 1 hour while the fan continues to help deice and warm the
air coil. After 1 hour the unit will attempt to restart. If the air temperature has increased
to the operational range the compressor will continue to run, otherwise the compressor
will return to the defrost mode for another 1 hour delay cycle.
You my experience some frost or icing on the outer air coil in cold weather tempera-
tures and is considered normal. If the air coil ices up, shut the heater off, allow it to
defrost and wait for warmer weather to restart the heater. If you live in an area where
the weather is expected to drop below 45˚F to 50˚F for an extended period you should
disable the heater during those times.
Page 7

1. Make sure the unit has a firm base. The heat pump will produce condensation
(water) while in operation. You will notice water coming from the bottom drain ports
when the unit is running. The condensation will increase as the outdoor air humidity
level increases.
Make sure the bottom drain ports do not become clogged with debris. Make sure the
run off water does not puddle inside the heater and does not undermine the equip-
ment base.
2. Keep the top air flow discharge & air flow intake area clear as shown here so the air
flow through the heater is not restricted. Make sure the unit can “breathe” well. The
cooler discharge air from the top should not accumulate and be drawn into the side air
intake coils. Keep all plants and shrubs trimmed away from the heater. Make sure the
front is accessible for future service.
3. Do not allow lawn sprinklers to spray on the heater in any way. Keep sprinkler heads
away from the heat pump to prevent corrosion and damage. Use a deflector if needed.
4. If the unit is installed under a very sharp roof pitch or under a roof valley that has no
gutter, a gutter or diverter should be fitted to prevent excessive water from pouring
through the unit.
Air Flow & Access Clearances
Heat Pump Maintenance & Precautions
AIR COIL
(on 3 Sides)
Page 8
BASE
(CONCRETE OR PREFAB)

This heat pump is equipped with the highest marine grade cupronickel alloy heat ex-
changer that is designed to resist corrosion from normal pool water. The life and con-
dition of the heat exchanger is directly related to the pool water chemical balance and
chemical usage techniques. The following precautions are required to help prevent
the possibility of corrosion damage to the heat exchanger. Chemical damage is not
covered and may void the warranty.
CHEMICAL FEEDERS & USAGE
1. All Chemical feeders must be installed as far “down-line” of the heater as possible.
2. A check valve and chemical trap loop must be installed between the heater and any
chemical feeders as shown here (and in the installation manual). The loop will help
prevent chemical backup into the heater.
3. All feeders should be installed at the same or below the heater piping elevation to
prevent chemical back up into the heater.
4. Do not install a chemical feeder on the suction side of the filter system. Feeders and
chlorinators installed on the suction side will discharge concentrated chemical or chlo-
rine into the heat exchanger before it is diluted with the rest of the pool water.
5. NEVER PLACE CHEMICALS IN THE POOL or SPA SKIMMER !
Chemicals placed in the skimmer will feed concentrated chemical or chlorine into the
heat exchanger before it is diluted with the rest of the pool water. Chemicals or chlo-
rine placed in the skimmer will dissolve and concentrate in the skimmer when the
water pump is off and then send a super concentrated chemical solution through the
heater every time the water pump restarts.
6. DO NOT STORE CHEMICALS NEAR THE HEATER !
Feeders, Chemicals & Water Balance
MINIMUM WATER BALANCE REQUIREMENTS
pH - 7.4 to 7.6
Chlorine - 1.0 to 5.0 p.p.m.
Alkalinity - 90 to 120 p.p.m.
Calcium - 200 to 350 p.p.m.
POOL WATER PUMP REQUIREMENTS
The water pump creates a vacuum on the skimmer line and the bottom floor suction
drain in the pool. If there is an imperfection in the filter system or plumbing, the pump
will draw air into the piping. This air will cause turbulence in the heat exchanger de-
creasing heat transfer and possibly causing physical erosion.
NOTE: Be advised that water pumps rated over 1.5 H.P. or over 70 gallons per
minute must have a plumbing bypass added to the exterior heater piping as
shown in the technicians installation manual. Be aware of this when upgrading
your existing water pump.
POOL WATER BALANCE
The following standardized water balance
values should be maintained to reduce the
risk of corrosion and/or mineral buildup
in the heat exchanger.
Page 9

Freezing Condition Precautions
In areas where extended freezing conditions exist, the heater must be plumbed as
shown here (and the installation manual), so it can
be winterized. Water left inside the heater will
freeze and cause damage.
This plumbing setup will allow the use of pressur-
ized air to clear the heat exchanger of water in
preparation for an extended freeze. This should be
done as part of your end of swimming season win-
terizing.
In warmer southern climates where freezing con-
ditions are temporary, you should run the water
pump 24 hours a day to prevent the water from
freezing inside the heater. Freeze damage is not
covered and may void the warranty.
Owner Maintenance & Cleaning
1. The heat pump will produce condensation water run off while in operation. Make
sure the condensation drains in the bottom of the heater cabinet do not become blocked
with debris. The condensation run off may attract increased plant growth and insects
in the heat pump area, be sure to keep all plants trimmed back and treat for insects as
needed.
2. The outer air coil (located on three sides of the heater), should be kept free of
debris and buildup. A minimal air coil cleaning should be done as needed and at least
two times per year. If the heater is installed in a sandy or salty condition, the air coil
should be cleaned more frequently.
3. To clean the air coil SHUT OFF ALL POWER, then use a garden hose at low pressure,
(without a pressure nozzle) to lightly rinse the air coil in an up and down motion. You
can use a mild soap while rinsing to help neutralize and clean. DO NOT spray water
directly in heater at high pressure.
4. Cabinet surfaces can be wiped clean with a towel and mild cleaner.
Professional Maintenance
The heater should be serviced regularly like any other machine. A factory authorized,
licensed air conditioning or mechanical contractor should perform the following main-
tenance procedures periodically.
1. Oil the fan motor.
2. Check the refrigerant charge.
3. Check the amp. draw.
4. Check all electrical supply connections & breakers.
5. Clean the air coil with approved solution.
6. Clean the interior cabinet bottom of debris.
7. Spray internal components with lubricant.
8. Inspect the installation including chemical feeder placement.
9. Inspect sprinklers to be sure the heater is not being sprayed.
10. Inspect for insect nests in and around the heat pump and treat.
Page10
You can contact the factory
@ 888-297-3826 for a list of
factory authorized service
centers in your area.

The heater will not heat faster if you turn the thermostat all the way up. The heater will
never run without water running through it from the pool/spa filter pump. When the
heater is started the fan will run right away. The compressor will start after a 5 to 7
minute delay. The heating light will come on only when the compressor is running.
The heater will produce condensation at a steady rate. The condensation exits the
heater from the bottom drains. The more humidity the more condensation. The ther-
mostat is accurate within three degrees and may not always match exactly to the de-
gree numbers printed on the control panel as it is effected by the humidity and other
factors. The heater is designed to shut off in defrost mode when the air temperature
drop below 45˚F to 50˚F. Page 11
Warranty Service
Before calling for warranty service you should check the following first:
1. Clean all filters and traps in the pool circulation system. Low water flow will cause
the unit to shut down or cycle.
2. Check and adjust all water flow valves and adjust to the proper positions to insure
proper water flow through the heater.
3. Check the water pump timer setting to insure there is enough time allotted for a
proper heating cycle.
4. Check all circuit breakers and disconnects. Note: More than one disconnect may be
required to shut off or turn on power to the heater.
5. Confirm that all heater controls, thermostat, thermostat selector switch, reset tripper,
and optional auto heat switch (if so equipped), are in the correct position.
6. If any 3rd party control devices are installed on the pool/spa system make sure they
are functioning properly. Factory service technicians will not diagnose 3rd party exter-
nal control devices. All external controls are disconnected during warranty service
and the heater is diagnosed as manufactured then reconnected.
7. The limited factory warranty does not cover damage or conditions caused
by but not limited to the following:
Improper installation.
Improper use.
Inadequate run time on the water pump timer.
Improper water flow to the heater.
Conditions caused or associated with 3rd party external controls.
Chemical damage or improper water balance.
Sprinkler damage.
Roof run off damage.
Freeze damage or operation damage during freezing conditions.
Salt and/or sand/debris damage.
Lack of maintenance and/or cleaning.
Unauthorized servicing of the heater during the warranty period.
Normal rusting and oxidation of metal components.
Non warranty service calls such as inspections, maintenance, or problems unrelated to
the heater as it was manufactured are not covered under the warranty.
8. You can contact the factory @ 888-297-3826 to be pre-qualified and scheduled
with a factory authorized service center in your area. Have your model number, serial
number and installation date ready.
Important Notes:

Water Pump
Starts Flowing
Water Pressure
SW Closes
Thermostat
Sensor
Heater
Stays Off
Low Pressure
Switch
Low Pressure
Switch Opens
LF displayed on LED
Low Pressure
SW Closed
All OK
LF Readout
Displayed on LED
T-Stat Relay
Closes
High Pressure
Switch
High Pressure
SW Closed
All OK
High Pressure
Switch Open
Heater Shuts Off
HP Displayed
Too Much Refrig.
or Low Water Flow
or Bad Hi Switch
Fan Starts
To Run, Green
Heating Light On
220V Power
To Heater
Green Power Light
On
Water Rises To
Set Temp.
Water Press. SW
Stays Open
No Water Flow
To Heater or
Bad Water SW
Compressor Runs
or 3 to 5 Min.
Delay Activates
Heater & Green
Heating
Light Go Off
Water Pump
Timer Activates
Compressor Stops
Fan Runs
T-Stat Relay
Does Not Close
Heater Does
Not Activate
After Delay Period
Try Again or
Possible Bad
Time Delay
Possible Bad
T-Stat Board, Pot
or Sensor
1 Hour Time Delay
Activates
Water Temperature
is Below Setting
Water Temperature
is Above Setting
Compressor Starts
Green Heating
Light ON
Time Delay Passes or
Air Temp. Increases
Safety Control Resets
Compressor
Restarts
or Below 45 to 50˚F
Air Temp or
Bad Low Press. Sw.
or Below 45 to 50
Deg. Air Temp
Operational Sequence & Troubleshooting Flow Chart
for “Digital Logic” Digital Control Models
TIME DELAYS
30 second compressor delay when switching pool/spa modes.
5 minute compressor delay when T.C.O. enables in pool mode.
5 minute T.C.O. off delay when: switching from spa to pool mode, when temperature is
reached in pool mode, or if LF (low water flow) is displayed on LED.
If water pump loses prime there will be a 3 minute compressor delay.
Page 12

Specifications may change without notice.
©2000 Calorex U.S.A. LLC
MEMBER
NATIONAL
POOL & SPA
INSTITUTE
Pool
Heat
Pump
Manufacturers
Association
MEMBER
5826 Corporation Circle
Ft. Myers Florida 33905
888-297-3826
www.calorexusa.com
[email protected]
U.S.A. L.L.C.