Does anyone know if there is a test or adjustment you can perform on honeywell gas valves. I have a lennox furnace with intermittent pilot. lately it has failed to light the odd time. When i go to check, the combustion fan is running but thats it. I turn off the power and gas valve and let it sit a few seconds turn it back on. if it doesnt light i rap on the side of the valve and it usually goes. Do i assume a faulty gas valve or is their test i can perform to be sure. Any ideas of the best/cheapest place to buy these?
thanks
dw
With a multimeter, and then compare the values to the specifications for the valve [which seem to be hard to come by].
A Websearch on your valve part number may turn up a test procedure.
If it's a 24vac valve I have a procedure and circuit for testing that your transformer is up to snuff. The parts for this test circuit may cost ~$10 or so, so if in doubt you may want to just swap out the 'frmr.
What is the model # of the furnace and gas valve? I am a Lennox tech. Rapping the valve is not a great idea as sometime it may stick open and become dangerous.
I think there is value in reducing uncertainty no matter how cheap the part is, even if it means spending a few bucks and an hour or so making a resistor network. This becomes more true for HVAC people.
But, many DIYers would rather swap out inexpensive parts even if the likelihood of it being bad is low.
In a way, it makes sense. It may be a poor bet, but they don't have much money & time riding on the gamble.
When the DIYer wants more certainty is when the part is very costly and likelihood of it being the root cause is unknown. Like replacing a part or replacing the whole furnace.
If there is 24.0vac across the valve and it doesn't work right, it is almost certainly the valve. But since current is what moves the valve I'd rather have a current reading and a voltage reading.
If it's >24vac, an open valve? Probably, since frmrs don't get 'stronger' and they usually have poor voltage regulation. Could also be a rusty connection.
If it's <24vac, a partially shorted valve winding or a 'weak' 'frmr? Which one?
If the OP does do the measurements, which one of these 3 readings and 5 possibilities will he/she find? Place your bets.
I have worked on thousands of furnaces and only had 1 weak transformer. They don't get weak as all there is in them is 2 windings of different size and insulation. Capacitors are another story. Sorry to disapoint you but there are NO values anywhere for resistance of gas valve coils etc etc. Nobody wants or needs them. Techs isolate the problem and change the part, period. The only spec we need are flame current, gas pressures etc. Our industry is not an electronic fixable one with Radio Shack parts and telling posters stuff that won't solve their problem only leaves them without heat longer, Sorry. There are also safety and liability issues and I don't tolerate advice which can compromise that. Circuit boards have critical flame failure circuitry and a DIYer with a soldering iron/static discharge etc can damage that and cause danger, period. I admire you wanting to help though.:thumbup:
Have no idea how they test them even if they do. My point is that not everything is on the net and searching for stuff that does not exist is futile. Hope you don't do a "Sonny Bono" someday. :laughing: We need interesting characters or the site gets too boring and I move on.
With EXTREMELY FEW EXCEPTIONS(the child murderers on the news as of late, are those exceptions). I never wish harm to anyone.
So I would not be wishing to see you break your neck..
However, maybe falling on your butt would be something I might wish for though. :laughing:
Kinda of like when I use to ride dirt bike. We always wanted to see one of us wipeout on a hill or jump. But never wanted anyone to get really hurt.
And seeing one of us get stuck in the mud boggs was always funny.
PS. Reading 24 volts across a valve, doesn't tell you if the valve is working or not.
Only tells you 24 volts is present.
Factory valve bench testing is easy. Input pressure on inlet side, Apply 24 volts, test for pressure on output side.
I would not recommend any diy to change out a gas valve. After the valve is in you must check for leaks, check the manifold pressure and also check temperature rise. That furnace I believe has a spark ignition and if it is the old johnson control it may not be operating correctly.
Yes a commercial dealer. I also do large custom homes and service. I install ans service just about everything from fireplaces to millions of btu makeup air systems. By the way I know you are good with control wiring what do you think of the IAQ with the true steam. I put in a few and think there pretty good.
Welcome Back!!! :thumbup: Our talent pool keeps getting better and better. Wish we could find your Ontario buddy TKG, I learned a lot from him and you and Houston.
Some people find the True Steam a bit small in large homes. Takes 4 mins to produce steam and in small homes the cycle could be 1/2 over by then. I have set them up with the IAQ system and G61's and like them. Need to clean the sediment out every yr.
so i tested the voltage across the valve from the red to orange and have 24 v after the furnace tries and fails to light. Does this mean the valve is faulty. After a few min the furnace i assume goes to lockdown and i lose that 24 v.
I shut off power and try again same thing happens 24 across the valve but then i traced the wires back and shook the re wire on control board a it fired right up so why if there was a loose connection would i still get 24v and the valve not operate?
Probably wasn't making good contact on the gs valve.
And when you shook it at the control board. it also moved at the gas valve. or you vibrated the furnace enough that it made better contact at the gas valve.
mv=main valve
pv= pilot valve
yellow is common
Should get 24 volts between yellow and pv first then 24 volts between yellow and mv. With voltage to mv and common you should have the gas valve open.
so i think i might have this narrowed down to possibly i have a faulty control. when the furnace fails to light i have no power at all from the control to the pv at the gas valve. if i shake the orange wire (pv) at the control the valve clicks on i have 24 v and the pilot lights . i have tried several times to clean and tighten the connection but it just doent seem to help so i am starting to beleive the problem may be in the control. Make sense to anyone? Also any good online sights i might find one it is a johnson G77 6RGD-2
thanks
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