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MrChaunse · Jan 5, 2013, 11:14 AM

I have a Goodman GMH80 gas furnace and it quite at the end of last season, I found that the pressure switch was bad electrically and replaced it with a new one. (I actually took it the old one apart to see what happened to it, I cleaned and realigned contacts and switch now works). Today I hear the blower (for exhaust) starting for a couple of seconds then stopping, keeps repeating, same as last time. I put in a new pressure switch which I had in stock and furnace works OK now. The one I took out has the same problem, it's bad electrically.
Any comments, should I replace it with a different brand (universal one like... Cleveland Controls)?
Thanks... Charlie

Grady White · Jan 5, 2013, 03:42 PM

Stick with the manufacturer's part unless you can find one with the same pressure spec. Manufacturers use pressure switches with specific pressure ratings for a reason & not all are the same.

MrChaunse · Jan 6, 2013, 07:50 AM

Thanks, the problem with the OEM one is that they're made in Costa Rica and fail often. The one that just failed was only in service for 3 or 4 months, they fail electrically. You can actually remove the electrical part (switch) of the sensor and see what the actual contacts look like, it's poorly designed. I wanted to know if anyone else has had this problem and what they did to resolve it.
The universal sensor I was talking about replaces a wide range of sensors and has to be calibrated to match the original sensor before it's installed, it is also made in the USA.

Thanks... Charlie

mygirlsdad77 · Jan 6, 2013, 12:17 PM

Vacuum in inches of water column is key when replacing a pressure switch, as you well know. If it has the rating on the switch itself, you can safely replace that switch with any "exactly same rating" switch of any brand. However, if the unit is still under warranty, only replace the switch (or any component of the system) with factory replacement parts to avoid voiding of the warranty. If the unit is out of warranty, and you have found the factory pressure switch to be problematic, by all means, use a different brand switch with the same rating. We do it all the time. Keep in mind, that the rating is very, very ,very important. Do not replace, for instance, a .4wc, with a .5. Or a 1.11 with a 1.2. It has to be exact match, if for no other reason than liability.