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· Registered
4 Posts
Discussion Starter · #2 ·
I replaced the exhaust fan, Swirlwind made by Fasco, unit cost of $583 for the third time in 8 years, because it seized up. The repair guy I took it to said the fan runs on bushing instead of bearings. There was adequate drainage around the fan so there was no h2o involved. There furnace was running fine until the fan seized up. My man replaced the bushings, I replaced the motor without incidence, turned the furnace on and the blower didn't start up. I've have called the local York repair centre and they sent me the manual by email but would not instruct me on repairs as I was an end user and not an official repair guy. Understandable where liabilities are concerned.
I checked both pressure switches with an ohm meter, suggested by a local furnace tech I used to work with at another industry. The switches indicated that they were open and not stuck shut. Hoses are all clear, drains are good, but I'm getting a flashing 3 code. Meaning: from the manual;​
This indicates the normally open pressure switch contact did
not close at the beginning of the heat cycle. This could be
caused by a number of problems; faulty inducer, blocked vent
pipe, high winds at vent terminal, broken pressure switch hose
or faulty pressure switch.
Pressure Switches
This furnace is supplied with pressure switches which monitor
the flow through the combustion air/vent piping system. These
switches de-energize the ignition control module and the gas
valve if any of the following conditions are present. Refer to
Figure 22 for tubing connections
1. Blockage of combustion air piping or terminal. (1LP)
2. Blockage of vent piping or terminal (1LP).
3. Failure of combustion air blower motor (1LP).
4. Blockage of condensate drain piping (2LP).

A question. Where's the condensate trap? Is that the tube running down from the top of the exhaust fan where the exhaust pipe and fan meet?

I've been working on this for 2 months. Lucky its been warmer of late.
I hope you can help me save some money helping solve this issue.



Model # PCLU- LD12N080A


· Registered
1,407 Posts
It seems you've caused this problem after changing the inducer fan. You need to check again all step.

the inducer fan should run when you call for heat.

· In Loving Memory
42,671 Posts
Until the inducer runs(what your calling the blower), the pressure switches can't close. So your problem is still with the inducer. Or the wiring to the inducer, or the board not providing power for the inducer to run..

2,427 Posts
agreed, It sounds like you had this inducer rebuilt, I would begin to question 1.) how it is wired. 2.) the repair of the bushings 3.) the control board it is attached to is not delivering power.

The pressure switch can not close unless the inducer runs..........

· Registered
4 Posts
Discussion Starter · #6 ·
The inducer fan was repaired by a qualified electrical engineer. He rewired the alternator for my 1990 Grand Prix and it ran for another 9 years without fail.
The fan is running and I don't have any doubt that its running correctly. Does the contact at the inducer and the exhaust pipe have to have an air-tight seal?
As you might be able to see, there are two points worth checking for seal breaks. At the top of the inducer fan about 14" up from that the white pipe meets the black one exiting the house 5 feet above ground.
Thanks for all your help guys but its seems I'm out of time. The gas company just shut off my gas today. But any suggestions are very welcome. I'll setup your ideas and I'll try to get back the gas line.
Thanks again
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