Gas Valve doesn't open fast enough
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  1. #1

    Gas Valve doesn't open fast enough

    Payne furnace 6 years old ran flawlessly until a week ago. Locks out due to no flame present. Random ignition as follows. When valve opens and first burner only lights, next four will light in time for flame sensor to register flame present, even though there is a noticeable delay in ignition. This happens maybe one out of 6 or 7 attempts. When first two burners ignite (almost simultaneously) last three burners will not ignite and furnace shuts down due to no flame present. This is most common scenario.
    Outlet gas pressure starts at 2.5" and slowly raises to 3.5 after approximately 4 seconds ( have to manually light burners to take this reading). Inlet gas pressure was 6" static and dropped to 5" after valve opens and lights. Replaced gas valve and problem still exists. Gas company changed meter and regulator and now inlet is 7" and drops very little when manually lighting furnace, but problem still present. Going a little nuts now, so I recheck everything including manifold alignment and all looks good. I just can't get the slow opening OEM valve to open fast enough to light all the burners before lockout. Any ideas?

  2. #2
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    I'm sure you checked, but are the crossovers dirty/rusty?

  3. #3
    Yes, I checked. Forgot to mention that in my original "long" post. Slid one piece burner assembly out and checked it. Actually, entire furnace looks brand new. Crossovers clean and evenly spaced (no crimping). Thanks though.

  4. #4
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    Sounds like you have it covered.

    I would try a universal fast opening valve to see if that was the problem.

  5. #5
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    Quote Originally Posted by chuckcrj View Post
    Sounds like you have it covered.

    I would try a universal fast opening valve to see if that was the problem.
    That could be opening up a law suit if you are considering that as a permanent fix. The last thing you want to do is is give the manufacturer that kind of ammo. "hey man it didn't ship that way'

    I agree with your idea in theory as I have seen slow open valves do all sorts of crazy things. I imagine that a slow open valve by it's very nature is going to compound any ignition problems.

    A spider in an orifice should cause the same problem on each ignition. I am guessing there is no air adjustment capability.

    Is this happening with the blower off or on?

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    Quote Originally Posted by Glennhvac View Post
    That could be opening up a law suit if you are considering that as a permanent fix. The last thing you want to do is is give the manufacturer that kind of ammo. "hey man it didn't ship that way'

    I agree with your idea in theory as I have seen slow open valves do all sorts of crazy things. I imagine that a slow open valve by it's very nature is going to compound any ignition problems.

    A spider in an orifice should cause the same problem on each ignition. I am guessing there is no air adjustment capability.

    Is this happening with the blower off or on?
    What drastic problem could putting a fast opening gas valve cause? Most induced draft furnaces have them, they must not be too dangerous.

    As for the liability end of it, if there is an incident and lawsuit, it won't matter if you installed the exact part. The manufacturer will still say it is the technicians problem. You didn't tighten the gas valve to the proper torque, you didn't use the right thread sealing compound/technique, you dropped it before you installed it, etc. etc. etc....

    You take on the liability as soon as you touch it.

    Do you test every furnace/boiler you touch for CO levels in the flue? If not you are taking a huge liability risk, way larger than simply installing a universal part. Some of the most dangerous furnaces I have found started out as a simple bad igniter or some other repair. If I hadn't tested and someone died, I would be in serious trouble. My combustion analyzer goes with me into the house on every service call right along with my ticket book and tool bag. I have seen 20 ppm ambient CO in 2 boiler rooms in the last 2 weeks alone.

    And I also agree that the partially plugged orifice could be causing this problem. I would check that before trying a different valve.

  7. #7
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    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...
    ..

  8. #8
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    Quote Originally Posted by landolb View Post
    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!

  9. #9
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    Quote Originally Posted by Glennhvac View Post
    That could be opening up a law suit if you are considering that as a permanent fix.
    Little known fact, from the moment you touch a furnace, you're "it" until the next sucker comes along and tags in.
    If more government is the answer, then it's a really stupid question.

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    Quote Originally Posted by mark beiser View Post
    Little known fact, from the moment you touch a furnace, you're "it" until the next sucker comes along and tags in.
    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.

    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.

  11. #11
    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.

  12. #12
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    Quote Originally Posted by Glennhvac View Post
    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.
    I agree completely.
    If more government is the answer, then it's a really stupid question.

  13. #13
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    And welcome to the site.

    We have a ton of good stuff on the pro section, after 15 posts you can apply for pro access.

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