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HVAC Dudes...

Discussion in 'General' started by Coopster, Oct 22, 2018.

  1. Coopster

    Coopster Well-Known Member

    Needed heat for the first time yesterday.
    Turn t/stat to "Heat", and set dial for desired temp.
    I can hear the fan spin up, and waiting for the gas to pulse, and light off, but NOOOoooooooooo.
    Watched some You Tube vids on "No light off" - figured it might be a bad igniter - scored one today, came home, installed aaaaaaaaaaaand same thing.
    The control panel has a light that blinks 3 times, gonna go online to see if that tells me anything...
    No gas is flowing, valve is on, gas water heater is working fine...

    TIA, Coop
     
  2. ChemGuy

    ChemGuy Harden The F%@# Up!

    Coop,
    Ive had the same issue. There is probably a small diaphragm switch looking for pressure differential to confirm the exhaust fan is on. If it doesnt see that it wont flow gas. Look for a small plastic thingy with a piece of tubing running to it from the exhaust port. On mine i had to take it out and kinda blow thru the tube and clean it out. It gets clogged and keeps the diaphragm from sensing pressure and telling the board to open the gas valve
     
  3. Coopster

    Coopster Well-Known Member

    Yes, forgot to mention that I already did that.
    Thanks,
     
  4. Kolbe

    Kolbe Well-Known Member

    @JBraun to the white courtesy phone...
     
  5. ChemGuy

    ChemGuy Harden The F%@# Up!

    Did you try to jumper that and make sure the switch isnt bad?
    If so time to call in a pro.
    I have a guy in Woodstock/Canton thats good and cheap.
     
  6. Coopster

    Coopster Well-Known Member

    Waiiiiiiiiiiiiiiiit!!
    OK, unplugged two leads from diaphragm, jumped those two wires together - we have flame!
    Getting new diaphragm sensor thang in the morn...
    Thanks!
     
  7. ChemGuy

    ChemGuy Harden The F%@# Up!

    Ha.
    I knew that was the cause.

    Ill put the bill in mail...:D
     
  8. ChemGuy

    ChemGuy Harden The F%@# Up!

    @JBraun We dont need know @JBraun ...pssshhh this shit is easy. Just start jumperin' shit till it works.
     
    badmoon692008 and JBraun like this.
  9. Kolbe

    Kolbe Well-Known Member

    Hold the @JBraun on that order please. :D
     
  10. Coopster

    Coopster Well-Known Member

    Blowing into the hose towards the fan motor it's deadheading.
    Sucking on the hose to the diaphragm switch I can hear the contacts clicking.
    Put a small zip tie down the brass barb on the fan motor for the vacum line attach, no difference.
    Maybe that end is blocked and can't pull a vacum...
     
  11. JBraun

    JBraun Well-Known Member

    @ChemGuy , not bad.

    Your new question is whether the pressure switch is broken, or if it’s just doing it’s job.

    The pro way is to connect a nanometer into the line and verify proper vent pressure. If you don’t have one, you can just pull the venting off and see if it runs.

    Check venting for obstructions and if it’s high efficiency, make sure the condensate trap is clean.

    Oh and don’t run it with that switch jumped until you’ve checked that stuff. It could real bad, mmkay?
     
    crusty9r likes this.
  12. JBraun

    JBraun Well-Known Member

    Sorry missed this earlier. Sounds like the port on the motor side is plugged. Get a drill bit or Allen wrench and clean it out.
     
  13. Coopster

    Coopster Well-Known Member

    10-4, thanks - that is what I tried to do with the small zip tie, but yeah, 1/8 " drill bit.
    I don't believe the vent is blocked, not sure how that could even be checked w/o a vid camera?

    Well damn, that didn't last long...
    The barb into the fan motor seems clear - a 1/8" drill bit hits bottom, but when hose is blown into in that direction, it's dead heading.
    THIS seems to be my cause of No Heat.
    I did have it running for quite some time with pressure sensor wires jumped...
    Am I gonna have to spend cash, important racing cash, btw, to get this chit fixed, mayne?!!!
     
  14. JBraun

    JBraun Well-Known Member

    Whats the model number on the furnace?

    Just noticed you said brass barb, so it’s an 80% furnace. Goodman?

    Still thinking that the nipple is plugged. They get so blocked that you actually have to drill it out sometimes. You should be able to slide the drill bit all the way into the housing until it touches the wheel on the inducer.
     
    Last edited: Oct 23, 2018
    Coopster likes this.
  15. ChemGuy

    ChemGuy Harden The F%@# Up!

    I've had mine blocked several times. It's in th basement/garage so dust, dog hair, etc builds up to pretty solid layer.

    Do you feel any suction at port when the exhaust fan is running?
     
  16. K51000

    K51000 Well-Known Member

    I have a furnace made by Armstrong- It says Condorde on it though. 90+% model.
    About 10-14 yrs old? Did the same thing.
    I tried to fix it myself by replacing the battery powered electronic thermostat- nope. $20
    Then I cleaned the sensing rod (my water heater needs this about once a year.- nope.
    Then I bought an OEM ignitor- $80 frick'n bucks!- still nope.
    We have one of those reusable filters- over 10 years old. Ya wash it out, vacuum it tdry thingy.

    Yea, I had the 3 blinking lights thingy.
    Watched the YouTubes- cleaned out all hoses and tubes- all were good anyways. Made sure the pipes to the outer wall weren't clogged too.

    Finally called a HVAC guy. $100 for the first hour of diagnostics, etc.
    The 3 blinks also mean the roll out switch on mine too.
    No video or manual told me that there is this little bitty red button on the little switch, that's right near the sensing rod and ignitor.
    He pushed that- fired up!!

    Turns out that old reusable filter- had clogged too much and was tripping the roll out b/c too much heat was building up cause it wasnt' flowing well.

    Bought new filters- We have heat!!

    Bottom line- change the filter; push the little red button on the switch, I'll bet it fixes it! I hope
     
  17. JBraun

    JBraun Well-Known Member

    Never call that guy again.

    That switch will only trip because of a flame roll out condition, meaning that the flame is rolling back into the burner compartment. It has nothing whatsoever to do with your filter.

    Your particular furnace is known for having heat exchanger issues. It's common for the rivets to fail on the primary heat exchanger which will cause that switch to trip.
     
    TurboBlew likes this.
  18. Coopster

    Coopster Well-Known Member

    Sorry, not brass - it is aluminum nipple - furnace is probably 15 yrs old, maybe 17.
    When I put the drill bit down the aluminum barb, it his something metallic, maybe an inch and a half in - I don't think it's a blockage, but there is ZERO suction at the other end (vacum switch) of the hose when connected to barb, and ex fan powered up.
    3 blinking lights is pointing towards clogged air filter? The thing looks good and is a few - 6 months old.
     
  19. Coopster

    Coopster Well-Known Member

    OK, I believe I now have it sorted.
    The 1/8 drill bit was too big - the hole in the bottom of the aluminum nipple is "metered" - not as large as the opening - a #55 drill bit opened up the corrosion plugged hole, and a #47 was about as large a bit as I felt was needed.
    I took the fan assy off the furnace to get a good look at it from the inside, probably did NOT need to do that, but #55 would not chuck up to a drill, and really most likely just needed to PUSH through the clog.
    I found a wiring staple inside the fan housing - hard to get good quality, not drunk fkkrz to do good work anymore!
    Thanks for all the help - I suspect I'll be firing this thing up in 15 minutes.
    Will blinking light reset automatically - I did not see the ubiquitous "Reset Button". 20181023_101746.jpg
     
  20. socalrider

    socalrider pathetic and rude

    if you disconnected the furnace power (you killed it when removing the front panel- see pressure switch) then when it starts back up it will self diagnose again. lights will be gone if you have fixed the problem.
     
    Coopster likes this.

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