Heater coil is on but goes out just as gas comes out

Need to know what make, model etc. High or medium efficiency???. If the exhaust blower is not spinning to pressurize the burner chamber it will not allow the gas to turn on.

if you hear the valve clicking but no gas the valve is bad.when the burner lights theres a probe that senses that it is lit and sends a microvoltage back to the controller to tell its lit.check to make sure all ground wires are grounded to a clean metal surface.

It sounds like the ignitor is not working, Since the heater is not detecting a flame it goes to lockout. Check the ignitor wiring to see if it is in good shape. Sometimes the connection where the wire (from the IID) connects to the ignitor gets corroded.

It could also be the IID which makes sure the safety loop is complete before calling for heat and sending current to the ignitor. Good luck with it.

You have to see if you're getting voltage across the coil on the gas valve. Measure across the MV and C terminals. The HSI (igniter) will have a warm up period of a few seconds before the gas valve is energized. So get the volt meter on it, if you get proper voltage it's a bad gas valve (or no gas supply) and if you don't get voltage it's the board!

Hello Sam,
What the most likely problem is,is weak gas valve coils,when teh coils are weak the flame comes on when they are cool but once the gas valve coils get warm the quit working. It is a fairly common problem,so common in fact i have written this tip covering weak gas valve coils http://www1.fixya.com/support/r10174506-gas_dryer_starts_off_hot_but_after_while
GENE

Than its going to be in your heat coil/ valves and your flame sensor. The flame sensor is a rectangle box on the flame tube. Your heater coils are on the gas valve they are two round silinoids one with two pins to it and one wwith three. Follow the gas line to the gas valve on the gas valve you will see two quick connects that run to it. There is one screw and the plate cover will come off to give you access to the heater coils.

If you have anymore question please comment me back

Heater is probably not coming on. What you hear running for about 30 seconds is the blower. After they blower comes on you should hear a obvious click. That is the igniter coming on. If you don't hear the click you have an electrical problem. If you do hear the click then either the heater is not getting gas - check the valves inside and outside the heater - or the flame sensor is not working correctly.

Good Luck

Hello,

Replace the booster coils you can purchase them form the link below,

http://www.appliancerepairlesson.com/

Change the flame sensor.

Since the pilot light stays on, and the main burner comes on momentarily, then goes out. This mean to
say that the gas supply is not steady, it also goes off.
You got to get your gas valve repaired or replaced to get
it working.