Low voltage to Igniter

Dryer Repair
1

After testing all parts of my gas dryer that I am able to, I have determined that the igniter is only getting about 28vAC and not glowing instead of a full 120vAC needed to function. Oddly, if I unplug the machine, disconnect the flame sensor, reconnect the flame sensor, and then operate the machine, the igniter will operate for one heat cycle. After the dryer heats up to the correct temp (2 minutes), and cools about 15 degrees, the heat relay switches but only supplies 28vAC to the igniter. The igniter never glows after the first cycle and the only way that I have found to energize it is to unplug the machine, disconnect the flame sensor, and repeat the above. The heat relay measures 0vAC (between RH and RH2 terminals) when it tries to energize the igniter just as it should. For kicks I swapped the motor relay and the heater relay but nothing changed. So, the relays are operating OK-just as the tech sheet I have outlines. What gives?

FYI-- The thermistor checks out OK at 13k ohms at room temp and drops when heated with a hair dryer. The thermal fuse checks OK for continuity. The high limit thermostat checks OK for continuity. The flame sensor checks OK for continuity. The igniter measures about 68 ohms. The gas valve coils measure the correct resistance.

Thanks in advance for any assistance.

2

Wiring harness might be breaking down under a load is is this a gas or electric dryer? You say it has motor and heater relay which I didn’t think gas dryers did that I recall.

3

[QUOTE=murderurfriends;362887]Wiring harness might be breaking down under a load is is this a gas or electric dryer? You say it has motor and heater relay which I didn’t think gas dryers did that I recall.[/QUOTE]

Thanks for your reply. It is a gas dryer and there are two relays. Is it true that the flame sensor, when heated, activates the coils and also shuts off the igniter? My guess is this is how the igniter shuts off when the flame lights. Am I correct?

4

I got lucky. A new flame sensor arrived today, I installed it and everything is fine. I thought about my problem for quite a bit and decided that all symptoms pointed to the flame sensor even though it tested OK.