You need a multi-meter to make this determination. If you have one set it on 2VDC, and take one probe and put it on the while wire from the pilot generator, and the other on the red wire. If you have 450+ millivolts (will show as .450) the pilot generator is fine. If you have less than (typically under 300) you need to replace/clean the pilot orifice, or replace the pilot generator.

Thanks for the followup.

I will check the generator first - have a tester but did not know the correct way to check it.

If the generator is indeed bad -- is there a safe way to check the valve?

That would save me the time in ordering the generator and then having to get the valve -- I would like to have this working for the 4th.

looks like if you need a valve the recommendation is to also get a new generator - sounds reasonable.

Unfortunately the valve is around $300 :(

Thanks again for your help-!!

Thanks for the followup.

I will check the generator first - have a tester but did not know the correct way to check it.

If the generator is indeed bad -- is there a safe way to check the valve?

That would save me the time in ordering the generator and then having to get the valve -- I would like to have this working for the 4th.

looks like if you need a valve the recommendation is to also get a new generator - sounds reasonable.

Unfortunately the valve is around $300 :(

Thanks again for your help-!!

"If the generator is indeed bad -- is there a safe way to check the valve? "

If the generator is indeed bad, no there more than likely isn't

Pilot generators are typically the problem, gas valve are pretty reliable. I think out off 400 heater repairs a season I personally perform I replace 2 gas valves.

Also make sure the pilot flame is strong. You should hear the pilot running and the flam should be at least 3/4" out of the pilot. If the pilot flame is weak (clogged orifice) it will reduce the out put of the pilot generator.

The pilot generators are very common many HVAC suppliers stock them. A honeywell 750mV thermocouple is what your heater uses, but a generic one should be easy to get if the honeywell one isnt available.

Connect the two wires from the generator to you meter, put it to VDC or volts DC at the lowest setting, if wires are reversed it will read a - before the reading on a digital, if analog the needle will try to go minus and you will need to swap the leads. We like to have at least 350 mv with the heater off and at least 200 mv with the heater running. Jump the gas valve and see if the reading drops, if it does not change the gas valve is bad due to an open in the coil, do not try to repair gas valve. If the voltage drops it could be either a bad valve,(shorted coil) or a weak pilot generator. Replacing both will always solve the problem.

I just got the valve to work - but I still need a little help.

My brother has my good tester - 15v is the lowest setting on the one that I have and it is a cheap tester. I was getting some movement on the needle and the pilot was staying lit so I disconnected the pilot tube from the valve and removed the whole pilot assembly.

The insulation on the wires to the generator were missing in some spots and the flame spreader for the pilot was off center to the generator. I cleaned everything up, moved the spreader, separated the wires and reinstalled the unit. I also turned the pilot all the way up. The valve now worked when I jumped the valve terminals!

So my plan is to get a new generator -- Honeywell if I can and install it. But the pilot looks a little weak even all the way up - how large should the flame be?

Can I assume that the pilot orifice is at the end of the tube just under the spreader? How best to clean? If not able to be cleaned do you replaced just the orifice or do you need to replace the whole tube?

If cleaning or just replacing the orifice is not an option and the whole tube must be ordered I want to order a direct replacement to make it easy and do it at the same time as the generator. The holder/ flame spreader is rusty but looks to be sound - I did not try to remove the pilot tube from the holder.

Anything special I should know about when reinstalling it?

Thanks again for all the help!