Intermittent Control System Troubleshooting - Empire Comfort Systems DVL25IN73N-1 Owner's Manual

INTERMITTENT CONTROL SYSTEM TROUBLESHOOTING

2
Main burner lights
when the pilot only
should light.
NO
Pilot holds the flame?.
YES
Main burner ignites?
YES
Main burner remains
ON
Main burner
modulates
properly?
29209-0-0911
1. Replace DFC board.
YES
2. Replace the gas valve.
1. Verify the pilot flame fully engulfs the tip of the sense electrode. If not replace the pilot
assembly.
2. Replace the pilot assembly.
3. Carefully clean the electrical connections of the sense cable, and the DFC board sense
cable connection.
NO
4. Replace the sense cable, or the cable-sense electrode assembly, or the pilot assembly.
5. Verify the pilot is properly grounded.
6. Replace the pilot orifice with a new orifice of correct size, and type, or replace the pilot
assembly.
7. If pilot flow adjuster screw is not sealed, correct it.
1. Verify the electrical connections' integrity and make sure they are in accordance with the
relevant system wiring diagram. If necessary replace the wire harness.
2. Check if the optional remote transmitter is in "thermostat" or "on" mode and verifyt there is a
call for heat (f using a thermostat remote). Adjust the setting for heat.
3. Verify that the pilot hood is properly fitted and a pilot flame is directed to properly ignite the
main appliance burner.
NO
4. Replace the main burner orifice with a new orifice of correct size and type, or replace the
pilot assembly. Under all circumstances follow the service instructions.
5. Remove the provided wiring harnesses from EV2 of gas valve (red base), and verify voltage
at ignition between the EV1 terminal and the ground connection on the valve body.
5.1 If the voltage is greater than 0 then Replace Valve.
5.2 Or Replace DFC.
6. Check the pressure at the outlet pressure test point out according to the manufacturer's
instruction. If not in accordance, replace the gas valve.
1. Verify the electrical connections' integrity and make sure they are in accordance with the
relevant system wiring diagram. If necessary replace the wire harness.
2. Check the pressure at the outlet pressure test point out according the manufacturer's
instruction. If not in accordance replace the gas valve.
3. With the system in the OFF position, connect the voltmeter between the EV2 terminal
NO
(green base) on the valve, and the ground on the valve body.
Turn the system ON, let pilot light, and observe the following voltage sequence: once the pilot
flame is proved, the voltage on EV2 should spike to approx. 5 VdC for approx. 2 sec and then
drop to approx. 0.6 VdC continuously.
3.1 If the sequence is respected, replace the gas valve.
3.2 If the sequence is not respected, replace the DFC board.
1. Replace the main burner orifice with a new orifice of correct size (partial blockage possible).
Verify that the main burner flame modulates. If it does not modulate replace the gas valve.
2. Verify that the gas valve outlet pressure limits are in accordance with the manufacturer
specifications. If not replace the gas valve.
FOR MANUAL HI/LO VERSION
3. Verify the flame changes while rotating the HI/LO knob on the front of the gas valve. If there
is no change replace the gas valve.
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