After a few decades I get it. In the end it will be us poor slobs no matter what happens. You are absolutely correct. I just can't see asking for even more problems by altering the design that furnace had engineered into it in order to pass testing for market. I will be the last to say I have not done my own alterations including changing older spark pilots to standing pilot.
Originally Posted by mark beiser
And yes most units that I am aware of come with a fast acting valve. I also know of furnaces and boilers where replacing a slow opening valve with a fast opening valve scared the heck out of me when they lit off! Try a fast opening valve on those old Bryant boilers once or for real kicks on those furnaces that used those goofy trumpet like burners.
I may be wrong. Maybe a fast opening valve will solve the problem. Why the furnace suddenly needs a fast open valve surely should mystify us I would think. The op said he replaced the gas valve. Unless there is a known issue with this models ignition I hardly think that out of the blue these units woke up and decided that slow opening valves were a poor choice.
While I am fully aware that many of you folks have as much or more time in the field than me I just feel that suggesting one to alter a units design is not the way to go.
This is an 80% Furnace. Payne Model PG8MAA036110ACJA.
I will recheck the orifices by removing them instead of just visual inspection when manifold was out. Burner is a one piece that slides out like a tray.
I'm hesistant to change to fast or normal opening valve, because of AGA rating and the fact that manufacturer did spec the slow opening valve. They actually use it on many of their models. I always thought they were used primarily on standing pilots, but I was educated.
All of you have great input, that I will use, but most of it I have checked. This valve (W/R 36G24) fits the small opening and is installed in a 90 degree pattern. Not certain if I could even get a different valve to fit in the cabinet. I'll let you know how it works out.
I agree completely.
Originally Posted by Glennhvac
Good luck and love to know what you find out. I'm guessing this was acting up with the fan off? A bad exchanger can cause havoc with ignition if it lights up with the blower on. Some units cycle the blower off anyway during a call for heat so that may not even apply.
Originally Posted by DrHeat99
One last thing and I could be totally off on this. It may be a draft issue. You may be just borderline on that air switch to fire up the burners but still have a weak draft. I have pulled dead birds out of inducers that were an erratic problem. You would think a bird in the inducer would be an issue on every call for heat but nope.
I usually find the control board is cutting off ignition too soon b4 the the valve opens.
There needs to be reasonable overlap between gas and lighting device.
4 seconds anyway...
Never had the valve the issue, sure lots of bugs and rust mess with the
crossovers. I often orally blow out the burners with a 3 ft hose, replaced
bad ones[burners] and found removing and washing with hot water/soap
really helps too..
Usually there is more than one way to resolve most problems
OEM gasvalve = good
I agree, check the orifices for bugs/spider web or something ?
Please clean the burners with water and blow out with nitregen.
Check the crossovers with a piece of sheetmetal 1/4 x 4".
Inspect your manifold and or burner alignment. This problem can occur if it is off, usually the Z axis.
could the space be in a negative pressure????????
is your venting negative??
looks like you covered everything?? maybe venting or combustion air????
true knowledge exists in knowing that you know nothing.
Ran fine with what has been there for 6 years.... and now there is a need for change in design?
Could it be that this thing is on crack? as in?
I had this same problem on a pg8 a couple years ago, i ended up moving the HSI a little closer at a slight angle to the burner and it started lighting perfectly. To reason with it i figured vibration might have moved the bracket
Just recently went to a gas furnace training for carrier, and they gave us a story on that. the guy had took the manifold out and hooked it up to a water hose to check if all the water was coming out evenly on each orifice. never heard this method before but sounds like another way of checking a clogged manifold or orifices...
Leave it to a training center to come up with this scheme. I have no doubt it would work but yikes!
Originally Posted by landolb
Had the exact same problem ...
I had the exact same problem on a Payne about 3 months ago. Don't remember the Model#.
Anyway, change the Hot Surface Igniter (HSI). What was happening for me was that the glow on the HSI would go out before the gas valve would open, hence no ignition. Replaced the HSI and all worked fine. No call back in 3 months.
Hope that works for you.