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UHA LOW PROFILE UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
38
SECTION 13: TROUBLESHOOTING
13.1 General
Ensure proper air flow
clearance for axial fan.
Open louvers slightly.
Replace axial fan if it does
not operate.
If problems persist, contact
Roberts-Gordon LLC at
www.rg-inc.com
Heater Operating
TROUBLESHOOT ENDS.
No
Replace limit switch.
The limit switch has
tripped. See Manual Reset
Limit Switch Figure.
No
Use Troubleshooting for
Automatic Ignition Burner
Systems section to test burner.
Has burner “Locked Out”?
Yes
No
With external controls (i.e.
thermostat) on, does the
burner continue through the
heating cycle?
No
Yes
Does the flue
blower run?
No
Use Troubleshooting for
Flue Blower section to test
fan.
Yes
Yes
Burner has locked out due
to ignition failure. Use
Troubleshooting for
Automatic Ignition Burner
Systems section to test
burner.
Is ignition control showing a
"2 flashes" LED code?
Yes
No
Yes
Fan and limit switch are
operating normally.
Replace temperature
limit switch.
No
Turn on supplies.
START
UHA 30 - 75: Press in reset
button on manual reset limit
switch. UHA 100 - 125: Wait
10 - 15 minutes for limit
switch to cool. Does fan
stop running?
No
Yes
Is ignition control showing a
"4 flashes" LED code
?
Yes
Are gas & electrical
supplies on?
No
Yes
No
WARNING
Explosion Hazard
Installation, service and annual inspection
must be done by a contractor qualified in
the installation and service of gas-fired
heating equipment or your gas supplier.
Turn off gas and electrical supplies before
performing service or maintenance.
Failure to follow these instructions can
result in death, injury or property damage.