WeatherKing Select 90 burners won't ignite?

Reply

  #1  
Old 10-21-10, 09:28 PM
Member
Thread Starter
Join Date: Oct 2010
Location: USA
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
WeatherKing Select 90 burners won't ignite?

WeatherKing Select Plus 90,000 BTU, 92.7% eff, 9 years old.

Draft Inducer blower (I think that is what it's called) starts as normal and runs for just over a minute, then shuts down. As far as I can tell, the burners never ignite, and the main blower motor never engages. I can feel exhaust pressure from the Draft Inducer blower at the pvc vent outside, and it appears to be the same as in the past.

If I remove the lower panel, and watch the electrical board as the furnace cycles, there are 2 green lights. The lower green light stays solid, the upper green light will begin to blink twice after about 15 seconds, and will continue to blink twice until the inducer blower shuts down at just over a minute.

Any Ideas on what to check for?

Thanks In Advance!!
 
Sponsored Links
  #2  
Old 10-21-10, 10:30 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Upvotes: 0
Received 0 Votes on 0 Posts
Check and see if you can locate the description of the diagnostic codes you are observing. Usually they are posted in the burner compartment or the door of the fan compartment.

What should happen is that the inducer motor should start and come up to speed. A pressure switch closes when the heat exchanger and venting system are operating safely, and then the rest of the ignition sequence proceeds.

Very like the pressure switch isn't closing. You need to use an AC voltmeter to check that.

If so, 95% of the time it's failing to close because of a plugged up heat exchanger or vent.

Checking it with your hand is not an adequate test.
 
  #3  
Old 10-22-10, 10:17 AM
Member
Join Date: Feb 2010
Location: usa
Posts: 623
Upvotes: 0
Received 0 Votes on 0 Posts
the pressure switch is a black circle, about 2 inches diameter with a rubber hose and a usually 2 wires going to it.
 
  #4  
Old 10-23-10, 08:56 PM
Member
Thread Starter
Join Date: Oct 2010
Location: USA
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
Thank you both for the replies.

I was able to locate the IFC troubleshooting flow chart. And the light blinking twice indicates "Pressure switch is OPEN", just as you suspected. The troubleshooting flow chart flows to blocked vent or "Replace Vent Pressure Switch".

I see what appears to be 2 different pressure switches (Thanks for the description). One has a hose running to the bottom of the draft inducer blower. The other has a hose running to the area below the burners. Is this the heat exchanger? Next to this hose is a larger rubber hose that feeds into a black cylinder that then connects to the pvc that drains the condensation. There is one additional hose feeding into this black cylinder draining condensation from the draft inducer blower. All four rubber hoses are clear of obstructions. I did not remove the black cyclinder that attaches to the drainage pvc to inspect for blockage. Should I?

Barring any undiscovered vent blockage, which of the 2 pressure switches might be my culprit? Or could it be either? Or both?

I do have a volt/ohm multimeter. I'm a novice at using it, but would be happy to check readings with a little guidance.

Again, Thanks for your help!
 
  #5  
Old 10-23-10, 09:02 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Upvotes: 0
Received 0 Votes on 0 Posts
Neither of the pressure switches are likely to be the problem 19 out of twenty times, you have a problem with the venting system or combustion system in the furnace.

Replacing the pressure switch is easy, but has about a 5% chance of fixing the problem. Suppose you spend $60 on a pressure switch. People (including too many repairmen) will spend $1200 on pressure switches before they replace one that's actually bad. Does that sound like a bargain?


If you can't identify the actual problem, call in a good repairman to find it for you. It's the cheaper and faster solution.
 
  #6  
Old 10-24-10, 11:26 AM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Upvotes: 0
Received 0 Votes on 0 Posts
If you think water maybe trapped in that bigger hose and could back up into the furnace, yes then, make sure it is clear.

To find out which switch is the one not letting the 24 volt currnt through, test them one at a time if you have to. The reason I say, "if you have to" is because on some pressure switches, you can actually see the plunger that gets sucked in. If you can see such plungers, then see if one is not being drawn away from the switch that the plunger bumps against.

If you have to test, first tell me if these switches have 2 or 3 wires going to them.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: