Roberts Gorden 125 - Manual (Page 44)

UHD L OW P ROFILE D UCT F URNACE I NSTALLATION O PERATION AND S ERVICE M ANUAL
36 of 47
14.2 Troubleshooting For Automatic Ignition Burner Systems
If problems persist, contact
Roberts-Gordon LLC at
www.rg-inc.com
Heater Operating
TROUBLESHOOT ENDS.
No
Trace fault in supervision
system. See
Troubleshooting
for Flame Supervision
System section.
Yes
Is ignition control showing
a "2 flashes" LED code?
No
Is the flame current at
least 1 μAmp DC when
the flame ignites?
Ignition control faulty;
replace.
See Ignition Control section.
Is ignition lead okay and
connected?
Is spark electrode okay?
Yes
Replace valve.
Is the gas valve operating?
To test valve, See
Troubleshooting for Gas
Valves section.
No Does the flame light? No
Yes
Wait 30 - 40 seconds.
Does ignition spark
operate?
No
Yes
Flue blower faulty;
replace
Burner control faulty or wiring
connections faulty. Repair
or replace as required
Check for too much vent/air inlet duct. Check for blockage in
vent and combustion air circuit. Check for faulty air pressure
switch. Check pressure switch hoses for leaks or cracks.
Do not attempt to circumvent pressure switch circuit to
place unit in operation.See Pressure Switch section for details.
Does air pressure switch
change over?
No
Yes
Is 120 V supply at fan
connections?
Does flue blower run?
No
Yes
Yes
No
Yes
Fan and limit switch are
operating normally.
Replace temperature limit
switch.
UHD 75: Press in reset
button on manual reset limit
switch. UHD 100 - 125: Wait
10 - 15 minutes for limit
switch to cool. Does fan
stop running?
No
Is ignition control showing a
"4 flashes" LED code? Yes
No
Yes
Turn on controls.
Are external controls
(i.e. Thermostat) on?
No
Yes
Turn on supplies.
Are gas & electrical
supplies on?
Yes
START
No
For optimum heater performance, use only replacement parts sold and supplied by Roberts-Gordon LLC.
Conduct start-up procedure as shown
on Page 26, Section 11.