Steffes 5120 User manual

Page 1 of 4 Document # 1200335 Rev 1
05/13/04
STEFFES CORPORATION
AIR HANDLER –¾ HP
For use with Model 5120, 5130, 5140 Comfort Plus Hydronic Heating Systems
The Steffes ¾ HP Air Handler (Item # 1302102) is an optional device used to interface the Comfort Plus
Hydronic with a centrally ducted heating or cooling system. The Air Handler includes a plenum assembly,
supply air blower, water coil, air filter, wiring harness, and hardware 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 supply air blower are energized. The pump circulates the hot
water through the air handler’s water coil and the supply air blower extracts the heat from the water in the
coil and delivers it to the appropriate heating zone through the ductwork. When connected directly to the
Comfort Plus Hydronic system, the air handler also directs heat lost statically into the living space providing
automatic static heat recovery. If used with a heat pump, the air handler has the ability to monitor the outlet
air temperature and provide comfort modulation as needed.
SPECIFICATIONS
Maximum Outlet Temperature 120 degrees Fahrenheit
Maximum Static Pressure .75 inches H2O
Maximum Water Coil Output 80,000 BTU/hr
Maximum A-Coil Size - Front Access 25.4"W X 22.25"H X 21.2"D
Inner Dimensions of A-Coil Area 26.4"W X 24.5"H X 21.2"D
Voltage 240/208 VAC
Wattage 1,300
Supply Air Blower 3/4 HP, 60 HZ
INSTALLATION
1. De-energize the Comfort Plus Hydronic system and unbox the
Air Handler.
2. Remove cover from the supply blower opening (Figure
1) of the Air Handler and locate the hardware kit.
3. Remove coil and filter covers. Then, remove the water
coil access panel of the Air Handler.
Hazardous Voltage: Risk of electric
shock, 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 1
12 7/8"
27 7/16"
OVERALL
Supply
Blower
"A Coil" Tray
Water Coil
Filter Tray
Return Air
36 1/16"
OVERALL
25"
23 1/4"
16 1/16"
60 1/8"
OVERALL
Air
Supply

Air Handler Instructions Continued…
Page 2 of 4 Document # 1200335 Rev 1
05/13/04
Connections
Air Handler Wiring
CORP ORATIO N
STEFFES
Conduit
4. During shipping, the water coil is held in place by one screw
on the right side panel of the Air Handler. Remove the screw
and lower the water coil into place. Secure the water coil and
the A-coil tray with the screws provided in the hardware kit.
5. Replace the five bottom, back screws on the right side of the
Comfort Plus Hydronic system with five of the 7/8” screws
provided in the hardware kit (Figure 3).
NOTE: Do NOT run the new screws all the way in. They
should remain out about 3/8”.
6. Tilt the Air Handler and set it onto the screws protruding from
the right side of the Comfort Plus Hydronic system (Figure 4).
Attach the Air Handler to the right side of the Comfort Plus
Hydronic system using screws provided in the hardware kit.
Refer to Figure 2 for placement of the Air Handler in relation
to the Comfort Plus Hydronic system.
7. Remove the two knockouts on the water coil access panel and
attach it to the Air Handler.
ELECTRICAL WIRING
1. Remove the electrical panel cover of the Comfort Plus
Hydronic system and locate the five (5) air handler
wires in the lower right side of the electrical
compartment.
2. Remove and discard the resistor connecting the two
brown wires.
3. Route wiring harness from the Air Handler to the
Comfort Plus Hydronic system through the conduit
(Figure 2) provided in the hardware kit.
4. Connect the wires from the Air Handler to the
corresponding colored wires from the Comfort Plus
Hydronic system. Refer to Air Handler Wiring
Diagram (Figure 5) or the Line Voltage Wiring
Diagrams in the Comfort Plus Hydronic Owner’s and
Installer’s Manual for more information.
5. Connect the green ground wire (Figure 5) to one of the
sheet metal screws that secure the circuit breaker stand off.
Figure 2
COM.
LOW
HIGH
WHITE
RED
BLACK
BLUE
Supply Air
Temperature
Sensor
Supply Air Blower
To Brown on Comfort Plus Hydronic
To Unit Chassis
Green
Brown
To Brown on Comfort Plus Hydronic
Brown
To Blue/Black on Comfort Plus Hydronic
High (Cooling) Speed - Blue/Black
To Blue/Red on Comfort Plus Hydronic
Low (Heating) Speed - Blue/Red
130 °
N.C.
AUTO RESET
To Blue/White on Comfort Plus Hydronic
Blue/White
MED
Figure 3
Figure 4
Figure 5

Air Handler Instructions Continued…
Page 3 of 4 Document # 1200335 Rev 1
05/13/04
Figure 6
PLUMBING
Installation of the water coil plumbing should be completed in a manner similar to the design shown in
Typical System Plumbing Diagram (Figure 6).
The Air Handler requires a dedicated pump (circulator) to feed the water coil and provide comfort
modulation. Steffes recommends a Grundfos UP15-42F single speed 115VAC pump or equal.
When utilizing the Steffes Air Handler, the recommended maximum water temperature (as set in
C011) is 180 degrees and the recommended minimum water temperature (as set in C012) is 160
degrees.
The 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.
It is extremely important to keep the area in front of the Air Handler 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.
White
Orange
White
Black Primary
Loop Pump
High Temp
Water
5100 Air
Handler
To
Other
Zones
Mixing
Valve
This Valve Must
Be Open During
Normal Operation
From
Other
Zones
Comfort +
Hydronic
Exchanger
Red
White
-
-
+
Low Temp Radiant Zones
Secondary Loop Primary Loop
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.

Air Handler Instructions Continued…
Page 4 of 4 Document # 1200335 Rev 1
05/13/04
AIR DELIVERY
1. Use the System Air Delivery Matrix to verify that the supply air blower speed is set correctly for the
application.
2. Install the supply blower cover and the A-coil cover on the Air Handler. Then, install the electrical panel
cover on the Comfort Plus Hydronic system.
3. Verify that the filter is in place in the filter tray, install the filter door, and re-energize the Comfort Plus
system.
SUPPLY AIR DELIVERY MATRIX
Supply Air
Blower Speed
Static Pressure (inches water column)
(External static pressure should not exceed .75 inches water column)
0.25
0.50
.75
High (CFM)
2030
1760
1500
Medium (CFM)
1970
1680
1425
Low (CFM)
1890
1630
N/A
MAINTENANCE & CLEANING
The filter in the Air Handler 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 with the Air Handler.
If utilizing a heat pump or air conditioner with the Air Handler, follow the manufacturer's cleaning
recommendations for those devices.