still no flame in gas furnace - new Gas Valve with 24V

[jjStar]

My Goodman furnace (GMP 100-5) usually give me some issues every year and I managed to learn/fix them during the past years.

This time, I thought I've narrowed this No-Flame issue down to a bad gas valve issue:

I got 24V on a multimeter after the Inducer was running, and the Ignitor was red-hot. (the operation sequence) --  I concluded the gas valve was bad

So, I ordered a White-Rodgers 36G22-254 gas valve and replaced it. no flame. I guess I got a defective one. ordered another one from a different seller... 

but still no flame...

 

Any Idea?  (yes, I have made sure there is gas flowing into the gas value: disconnect the gas valve and turn on and off the gas shut valve quickly. there's gas coming out with "pshhhhh" sound )

 

 

 

 

(some more details --

actually, this is my 2nd White-Rodgers: I changed the existing Goodman gas valve 2 years back and fixed the issue.

And this time, I also did some more researches before ordering the new White-Rodgers gas value -- I disconnect the wires going to the gas valve, and measured the voltage on the wires. Yes, it had the 24V AC reading after the Ignitor was red-hot.

Also, I measured the resistance of "the gas valve coil" - I guess it should have ohms, but I got a open circuit reading on both new White-Rodgers valves... it looks like  some new-type gas valve wouldn't get 300~2000 ohms How to test the gas valve on a gas furnace with an ohmmeter)

 

 

 

 

[ECtoFix]

Why would you disconnect the wires to the gas valve in order to test voltage?  That's counter-intuitive to the valve's operation. 

You need to be testing for proper input voltage while the wires are connected to the valve.  In THAT way, you are doing several things PROPERLY:

• You'd be testing for voltage under the conditions which the problem occurs.
• You'd be testing performance/integrity of the INCOMING supply wires, connections, the relay...and the SOURCE - ALL while under the load it's designed to carry.

In YOUR testing scenario, you did NEITHER.  I place emphasis on that because, WITHOUT A LOAD, a poor/iffy wire connection or badly pitted relay contacts (on the control board) might VERY WELL deliver your 24v to carry just the MINUSCULE load of your meter, but might not be adequate enough to carry the amp or two that the gas valve demands.

ADDITIONALLY-

Since I can't be there looking over your shoulder to see what you're looking at and how you're testing it, I ALSO have to wonder where you'd placed your voltmeter test leads while taking your reading: 

• If you went a placed one test lead to GROUND, then STOP doing THAT!  Although one side of the 24v transformer might be BONDED to ground, that only done for safety reasons. 
• GROUND does NOT make a reliable place to be testing from when there may be a run of wires and connections between ground and your valve. 
  • This, of course, depends on the circuit's design.  I HAVE seen some gas valves with on terminal fed straight from ground.
• Using GROUND as a test point means that you're completely overlooking tests of that entire leg leading to your gas valve.  Make your voltage reading DIRECTLY FROM THE TWO INPUT TERMINALS of the valve.

By the way, as graymanfurnace alluded to in his video that you linked, you're probably NOT going to be able to read resistance with an OHMMETER through the gas valve due to the electronics board in it.

[buttler joseph]

According to my experience the problem lies with the new White-Rodgers gas valve, as you've confirmed that there is gas flowing into the gas value and that you have 24V AC reading on the wires after the igniter is red-hot. However, you're getting an open circuit reading on both new White-Rodgers valves, which suggests that there's a problem with the valve coils.

It's possible that you've received two defective valves, or that there's an issue with the compatibility between the White-Rodgers valves and your Goodman furnace. It would be a good idea to contact the manufacturers of both the valve and the furnace repair to see if they have any recommendations.