Steffes HPB22 Troubleshooting Guide - Manual (Page 7)

Page 5
Heat Pump Booster
Function: Air Delivery
Problem: Blower does not run
Before starting any of the procedure below, check voltage on load side of all HPB circuit
breakers. Check for 24 VAC between each of the low voltage fuses and the "C" position on the
charge controls circuit board's terminal block. Put heater into peak mode.
Initiate a peak mode.
Check for 24 VAC across "R" and "C"
terminals on booster interface board (21).
Jumper terminal "R" to "W" on
the interface board (21).
Troubleshoot and repair
field wiring.
Voltage present No voltage
Check for operation
of fan relay (54).
Check field wiring
and wall thermostat.
Motor runs
Motor does not run
Check voltage at
relay coil.
Check supply voltage to
core blower motor (38).
Relay will not operate
Relay closes
Replace interface
board (21).
Replace fan
relay (54).
No voltage
Voltage
present
Check unit wiring and
fan limits (44 & 27).
Replace core
blower motor (38).
Improper
Voltage
Proper
Voltage
Page 6
Initiate a peak mode.
Check for 24 VAC across "R" and "C"
terminals on booster interface board.
Jumper terminal "R" to "W" on
the interface board.
Troubleshoot and repair
field wiring.
Voltage present No voltage
Check for operation
of fan relay.
Check field wiring
and wall thermostat.
Motor runs
Motor does not run
Check voltage at
relay coil.
Check supply voltage to
core blower motor.
Relay will not operate
Relay closes
Replace interface
board.
Replace fan
relay.
No voltage
Voltage
present
Check unit wiring and
fan limits.
Replace core
blower motor.
Improper
Voltage
Proper
Voltage
Check system
wiring.
Closed
Replace fan limit
switch(es).
Open