Direct Gas Make-Up Air
56
Troubleshooting
Direct Gas-Fired Heat
Problem: Heater does not modulate correctly. Maxitrol 14 Series system.
Is fan operating correctly?
Yes
No
Refer to Troubleshooting, Supply Fan.
Is the burner operating and lit?
Yes
No
Refer to Troubleshooting, Direct Gas-Fired Heat.
24 VAC at terminals 38 and 39?
Yes
No
Transformer TR6 faulty.
Replace transformer.
Remove the wire from terminal 3 on
the Maxitrol Amplifier (AMP). 24 VDC to
modulating valve (MOD)?
Yes
No
Amplifier (AMP) faulty.
Replace amplifier
Burner operating at high fire?
Yes
No
High fire adjustment not set correctly.
Adjust high fire setting.
Reference Start-Up: Direct Gas-Fired Heating, Industrial or
Commercial Pilot Systems.
Inlet gas pressure too low to provide high fire.
Increase inlet gas
pressure to above the minimum input for maximum output value.
Modulating valve (MOD) stuck.
Tap valve gently to loosen
Modulating valve (MOD) faulty.
Replace modulating valve.
Reconnect wire to Terminal 3. Remote
dial connected to terminals 1 and 2 on
the Maxitrol Amplifier (AMP)?
Yes
No
Connect remote dial.
If a remote dial is not required, set the Selector DIP switch to Integral
to allow the onboard set point to control the discharge temperature.
If this is set to Integral.
Is the 'Selector' DIP switch set to
'Remote'?
Yes
No
Set the 'Selector' DIP switch to 'Remote' to allow the remote dial
to control the discharge temperature.
Is the 'LFST' switch set to '10 Sec'?
Yes
No
Set the 'LFST' DIP switch to '10 Sec' to allow the main portion of
the burner to ignite at low fire.
Remove the wires from terminals 1
and 2 on the Maxitrol Amplifier (AMP).
Check resistance between the two
wires. Is the resistance in the range of
9000-13000 ohms?
Yes
No
Remote temperature dial (TS3) wired incorrectly.
Correct wiring.
Remote temperature dial (TS3) faulty.
Replace remote temperature
dial.
A remote temperature dial failure will usually result in a reading of
infinite or zero resistance between the two wires.
Remove the wires from terminals 3
and 4 on the Maxitrol Amplifier (AMP).
Check resistance between the two
wires. Is the resistance in the range of
5000-13000 ohms?
Yes
No
Discharge temperature sensor (TS2) wired incorrectly.
Correct
wiring.
Discharge temperature sensor (TS2) faulty.
Replace discharge
temperature sensor.
A discharge temperature sensor failure will usually result in a reading
of infinite or zero resistance between the two wires.
Everything is working properly, consult factory.
