Steffes 5100 Series User manual

VARIABLE SPEED AIR HANDLER
INSTALLATION INSTRUCTIONS
FOR 5100 & 7100 SERIES
Page 1 of 5 Document #1200365 Rev 11
03/19/2021
The optional Steffes ½ HP (Item #1302132 and ¾ HP (Item #1302134) variable speed air handlers are used to
interface a Comfort Plus Hydronic with a centrally ducted heating or cooling system. Each air handler includes
a plenum assembly, variable speed supply air blower, water coil, air filter, and installation kit.
OPERATION
When the Comfort Plus Hydronic system receives a heat call from the air handler’s room thermostat, the
primary loop pump (circulator) is energized to circulate water through the heat exchanger. At the same time,
the air handler’s pump (circulator) and the variable speed supply air blower are energized. The pump circulates
hot water through the air handler’s water coil and the variable speed supply air blower extracts heat from the
water in the coil and delivers it to the appropriate heating zone through the ductwork. Since the air handler is
attached to the side of the Comfort Plus Hydronic system, it also provides automatic static heat recovery. If
used with a heat pump, the air handler monitors outlet air temperatures and provides comfort modulation.
SPECIFICATIONS & DIMENSIONS
NOTE: If using the ¾ or 1 HP Air Handler, the 90,000 BTU/hr coil output may decrease when using an
A-coil smaller than 5 ton.
1/2 HP
3/4 HP
Maximum Static Pressure
.75 inches H2O
.75 inches H2O
Maximum Water Coil Output (See Note)
60,000 BTU/hr
90,000 BTU/hr
Maximum A-Coil Size - Front Access
22 5/16” W x 30” H x 22 3/4” D
25 5/16” W x 33” H x 22 3/4” D
Voltage
240/208 VAC
240/208 VAC
Full Load Amps (240/208V)
4.3/5.0
6.8/7.3
Supply Air Blower
1/2 HP, 60 HZ
3/4 HP, 60 HZ
Filter
20” x 20” x 2”
20” x 25” x 2”
Standard Copper Pipe Size
3/4”
3/4”
½ HP
23.5”
23.69”
72.69”
26.5”
23.69”
75.69”
¾ HP
Figure 1
Filter Access
Coil Access
Blower Access
Supply Air
Outlet
Figure 2
Cold Air
Bypass

Variable Speed Air Handler Instructions(continued). . .
Page 2 of 5 Document #1200365 Rev 11
03/19/2021
INSTALLATION
THIS PROCEDURE MUST BE PERFORMED BY A QUALIFIED TECHNICIAN
NOTE: Per UL requirements, the air handler must be mounted to the right
side of the Comfort Plus Hydronic system. Reference Figure 2.
1. De-energize the Comfort Plus Hydronic system and unbox the air handler.
2. Remove the blower and coil access covers from the air handler (Figure 2).
3. Remove the air handler base from inside the air handler.
4. Remove the filter from the base and locate the hardware kits.
5. Mount the air handler base to the base of the furnace using the index holes
as shown in Figures 3 and 4. Figure 4 is, as viewed, looking up and into the
base of the air handler. Screws for attaching the base are included in the
hardware kit.
6. Install support brackets, as shown in Figure 5.
7. Cut a return opening into the base of the air handler. The return should be sized
for the installation and can be cut into any one of the three available sides or the
bottom of the air handler base below the filter assembly.
8. Set the air handler onto the air handler base. Attach the two together using eight
of the screws provided in the hardware kit. There are two screws per flange.
9. Attach the side of the air handler to the top of the furnace using the 1” x 22” L-
bracket shipped in the supply air outlet (Figure 2) and six of the self drilling
screws provided.
10. Attach the cold air bypass to the right side of the air handler. Bypass allows air
to cool the motor (Firgure 2).
11. Loosen connector nut on the flexible conduit approximately 1/8”. Slide connector
into slot as shown in Figure 6. The washer and nut must
be on the inside of the panel. Snap strain relief bushing
into place.
12. Remove the electrical panel cover of the Comfort Plus
Hydronic system and locate the air handler wires in the
lower right side of the electrical compartment. Remove
and discard the resistor connecting the two brown wires.
13. Attach the 1/2" flexible conduit connector to the air
handler’s umbilical cord and furnace. Reference Figure 8.
14. Connect the wires from the Air Handler to the corresponding colored wires from the Comfort Plus Hydronic
system (Figure 9). Connect the green ground wire to one of the sheet metal screws that secure the circuit
breaker standoff.
•Hazardous Voltage: Risk
of electric shock. Can
cause injury or death.
System may be connected
to more than one branch
circuit. Disconnect power
to all circuits before
installing or servicing.
Equipment must be
installed and serviced by a
qualified technician.
•High Temperatures: Risk
of personal injury. DO
NOT install Air Handler
when outer surfaces of the
Comfort Plus Hydronic
system are hot.
WARNING
Figure 4
Figure 3
Support
Brackets
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9

Variable Speed Air Handler Instructions(continued). . .
Page 3 of 5 Document #1200365 Rev 11
03/19/2021
15. Connect the 7-pin harness to the “Blower” port on the LV circuit board (Figure 10).
16. If an outdoor sensor is used, connect the
sensor wires to the “Outdoor” terminals
(Figure 10).
17. If utilizing low voltage peak control, connect
the peak control device to Peak Input
terminals “RP” and “P” (Figure 10).
18. Using the chart below, select the proper
“Blower Speed” at the LV circuit board. See
Figure 10.
19. The “W-E” jumper MUST be in the “OFF” position.
NOTE: If the W-E jumper is “ON” when installed in a hydronic heating system, the air handler will
run with an “H” call from the thermostat. See Figures 11, 12, and 13.
20. If installing a system with a two-stage heat pump, the Y1-Y2 jumper must be placed in the “OFF” position.
NOTE: If using a two-stage heat pump, a “Y1” signal will yield half of the maximum CFM selected. A
“Y2” signal will yield maximum CFM selected. See Figures 11, 12, and 13.
21. Connect field wiring from the room thermostat to the LV circuit board using the appropriate wiring diagram
from the “Room Thermostat Interface” section of these instructions.
ROOM THERMOSTAT INTERFACE
The variable speed ECM motor adjusts motor speed to achieve the appropriate CFM for the thermostat input
received. The maximum CFM required is selected at the LV circuit board during installation.
Jumper ½ HP Variable
Speed CFM
¾ HP Variable
Speed CFM
A
1000
1200
B
1200
1400
C
1400
1600
D
1600
2000
Figure 10
Outdoor Sensor Connections
Low Voltage Peak
Control Connections
7-pin Harness
Blower Speed
Selection
NOTE: Generally, 400 CFM of air flow is
recommended per ton of cooling.
Therefore, a 3-ton heat pump or air
conditioner requires 1,200 CFM.
W/
NO NC COM Outdoor Outdoor
CR
H/E
The Y1/Y2 Jumper must be installed
RLY1 D6
To Control Board
Fid 2 D4
Blower
To Control Board
O
D3
R2
R1
D7D5
P11
W E
Y1 Y2
Water
J4
D1
P5
J1 J2 J3
P10
P6
D2
D A B C
C3
J5 J6
Blower
Speed
P4 P3
AUX Y2 G
Y1 O
22
Y2Y1
R
Air
LV Circuit Board
Comfort Plus
P7
P8
P2 P1
C
P9
RP
2
APP
Aux.
Relay
Peak
Inputs
G
TH5110D
R
C
W
Y
Honeywell
R c
(If being used in the application)
Air Conditioner Connections
C
Y
The W/E Jumper must be removed
Hydronic Heat Thermostat, Zone
Valve, End Switch, or Pump Control
A B C D
W / E
Y1 / Y2
J1 J2 J3 J4
J5 J6
Blower
Speed
* If multiple inputs are active, system will
display highest Heat Call values. "COOL"
overrides all inputs and stops all heating
operations.
** Thermostat must be programmed to energize
reversing valve for cooling, even if outdoor
unit used requires the reversing valve be
energized for heating.
Figure 11
Stand Alone Furnace Application Connections
Shown for Single Stage Heating / Single Stage Cooling
(Uncontrolled Air Conditioning)

Variable Speed Air Handler Instructions(continued). . .
Page 4 of 5 Document #1200365 Rev 11
03/19/2021
Honeywell TH5220D
Outdoor Sensor
The Y1/Y2 Jumper must be installed
The W/E Jumper must be removed
Peak
Inputs
Aux.
Blower
Figure 12
Single Stage Heat Pump Application
* If multiple inputs are active, system will
display highest Heat Call values. “Cool”
overrides all inputs and stops all heating
operations.
** Thermostat must be programmed to energize
reversing valve for cooling, even if outdoor
unit used requires the reversing valve be
energized for heating.
Hydronic Heat Thermostat, Zone
Valve, End Switch, or Pump Control
Honeywell TH5220D
Y1 - Compressor
C - Low Voltage Common
R - Low Voltage Hot
Y2 - Compressor Stage 2 O
- Reversing Valve
Outdoor Sensor
Spee d
R C
Comfort Plus
LV Circuit Board
Blower
Figure 13
Two Stage Heat Pump Application
* If multiple inputs are active, system will
display highest Heat Call values. “Cool”
overrides all inputs and stops all heating
operations.
** Systems built before 1/1/2011 are
configured for 50% airflow in Stage 1. For
more information, refer to Instruction
#1200601-High Speed Stage 1 Relay
Installation.
*** Thermostat must be programmed to
energize reversing valve for cooling,
even if outdoor unit used requires the
reversing valve be energized for heating.

Variable Speed Air Handler Instructions(continued). . .
Page 5 of 5 Document #1200365 Rev 11
03/19/2021
PLUMBING
Installation of the water coil plumbing should be
completed in a manner like the design shown in
Typical System Plumbing Diagram (Figure 14).
 Standard copper pipe size 3/4".
 Dedicated pump (circulator) to feed the water
coil and provide comfort modulation. Steffes
recommends a Taco 007 single speed 115
VAC pump (Order Item #1100002) or equal.
 Maximum recommended water temperature
(as set in C011) is 180ºF/82ºC and the
minimum recommended water temperature (as
set in C012) is 150ºF/65ºC.
 Pump serving the air handler is powered with
the black and white wires found in the junction
box on the lower left side of the Comfort Plus
Hydronic system. Refer to the Plumbing
Section of the Comfort Plus Hydronic Owner’s
and Installer’s Manual for more information.
 Area in front of the air handler must remain
open for accessing the blower, filter, and coils.
NOTE: It is the responsibility of the installer to prevent involuntary flow of the water to the air
handler. Not doing so may cause limit tripping or decreased heat pump efficiency. Use of a
check valve, zone valve, etc. may help in this situation.
PLUMBING
The Air Handler filter should be replaced on a regular basis and general cleaning of the cabinet should be
conducted at the user’s discretion. No additional routine maintenance is required. Replacement filters can be
ordered from the factory (Order Item #1159017 for ½ HP and #1159063 for ¾ or 1 HP).
If utilizing a heat pump or air conditioner with the air handler, follow the manufacturer’s cleaning
recommendations for those devices.
WARNING
Risk of personal injury or property damage. Water
temperatures used for the Air Handler may not be
acceptable for other heating zones in the installation.
It is the responsibility of the installer to ensure that
proper tempering devices are in place.
FREEZE PROTECTION: Risk of frozen pipes. Can
cause property damage. Hydronic heating system
freeze-ups WILL cause extensive damage to the
entire heating system and/or property. Damage to the
air handler piping system can occur in low ambient
temperatures conditions or can be caused by a
system malfunction during air conditioning mode. It
is the responsibility of the installer to protect against
freezing of all plumbing and water coils.
PIPING SUPPORT: Risk of exchanger damage. Can
cause property damage or personal injury. DO NOT
use the exchanger as support for piping. Support
brackets should be in place to ensure proper
operation of the system and to keep pressure off the
inlet and outlet piping.
Secondary Loop
Primary Loop
Figure 14