# Comfortmaker RPJ - 3 Flashes - Pressure Switch Contacts Open



## hvaclover (Oct 2, 2008)

Seems like you are getting on again off again problems. 

Answer me this: do you have a chimney liner?


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## olgranddad (Jan 1, 2007)

"do you have a chimney liner? "

How do I tell this? I do have a gas fireplace, but it is far from the furnance.


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## hvaclover (Oct 2, 2008)

Ok first i need to know if you have a 80% or 90% efficient furnace.

80% vents into the same chimney as the old one but has a liner in it to stop chimney condensation and the furnace and the water heater are vented into a wye connection which in turn connect into the flexible chimney line

A 90% has plastic PVC pipes that vent out the side wall.

Press switches trip for diff reasons on theses furnaces.

Gimme a model number if you can...it will help.












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## olgranddad (Jan 1, 2007)

I don't see any PVC. I do see a why connection for the exhaust of the furnace and the water heater. I track it up through the floor, but then have no idea here it goes. It looks like it is going away from the fireplace. So 80%?

I don't see any energy efficiency rating on the furnace. It could be worn of as the furnace is from 1994.

What I can see is...

Comfortmaker RPJ II
Part Number 7402-491 - This may be a controller part number
Model Number GUI100A012BIN
VAC 115/120
PH 1
Hz 60
Input Amps 12

There aren't any other identifiers.


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## hvaclover (Oct 2, 2008)

Replace the press switch.


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## olgranddad (Jan 1, 2007)

That is what I thought I needed to do. What I don't know is which switch is the pressure switch. Can you describe what it should look like? Is it purely electrical or is it the solenoid switch that controls the gas flow?

Thank you for your help


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## hvaclover (Oct 2, 2008)

Rubber tube comes off the inducer motor. It connects to the press switch.

Switch is round and has two or more wires coming off it.


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## olgranddad (Jan 1, 2007)

Ok I just had my first chance to look at the pressure switch. When I pulled the rubber hose off, I noticed that there was a hard spot in the tube. It looks like water corrosion buildup. It was blocking the tube. I cleaned it out. I also cleaned up the output on the condessor where the tube attaches.

I put it together and turned the furnace back on. It fired right up. I am watching it right now to see if that fixed the problem.

If this was the true issue Ill be thankful for heat. However, the next question is...should I have been checking that tube for buildup as normal maintenance? Or is this an early sign that something else is going wrong because I did get corrosion in the tube?

Once again thanks for the help with the heat


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## hvaclover (Oct 2, 2008)

The build is from not having a chimney liner,


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