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Old 01-15-2012, 10:29 PM   #16
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Strange pressure switch problem


The furnace was engineered for a specific pressure to be measured by the pressure switch. The safety of this, for
example, is shutting down the furnace if the inducer motor is not pulling enough burning gas through the exchanger to prevent it flooding out the front of the furnace and destroying what ever it can reach.
The adjustment of the pressure switch, without a manometer check, and the info of what that pressure should be closing at is to compromise it's ability to prevent something like that.

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Old 01-16-2012, 08:21 AM   #17
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Strange pressure switch problem


now you have a DANGEROUS situation. you can have a flame backup and rollout from not enough draft and SERIOUSLY damage the furnace. need a new pressure switch ASAP. they put glue on the adj threads so it is illegal to tamper with it and for liability reasons.
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Old 01-16-2012, 08:33 AM   #18
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Originally Posted by how View Post
The furnace was engineered for a specific pressure to be measured by the pressure switch. The safety of this, for
example, is shutting down the furnace if the inducer motor is not pulling enough burning gas through the exchanger to prevent it flooding out the front of the furnace and destroying what ever it can reach.
The adjustment of the pressure switch, without a manometer check, and the info of what that pressure should be closing at is to compromise it's ability to prevent something like that.
Basically you are playing Russian roulette with your furnace.......
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Old 01-16-2012, 09:29 AM   #19
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Strange pressure switch problem


Okay, that's why you guys are here. Furnace shut down, repair part ordered.
Thanks for saving my furnace and possibly house.
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Old 01-16-2012, 09:41 AM   #20
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Strange pressure switch problem


And for any other DIYers ( as lots read these posts ) DO NOT ever tamper with a pressure switch settings.
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Old 01-16-2012, 10:00 AM   #21
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Okay, that's why you guys are here. Furnace shut down, repair part ordered.
Thanks for saving my furnace and possibly house.
what technical means did you use to come to the conclusion that your pressure switch is bad? ( its bad now due to you tampering with it). you HAVE TO USE SOME TYPE OF MANOMATOR OR MAGNIHELIC GAUGE to determine the amount of draft that your combustion motor is pulling, other wise you are just guessing that the pressure switch is the problem. You could very well have issues with your primary and or secondary heat exchangers that only a professional trained HVAC service technician would be able to find.

Nothing wrong with a H-O doing some things DIY, but like the beer commercials say......know when to say when, or in your case "i am in over my head and past the point of my knowledge, its time to call in the pro's and have it fixed right".
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Old 01-16-2012, 10:17 AM   #22
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Strange pressure switch problem


I have read numerous posting on the web (1 technical alert from the manufacturer) that the switch is prone to failure. I felt forceful air movement at the intake and exhaust outside. I knew the pipes were clear. I could feel significant suction on the blower side of the differential switch. I could see the flames going into the burner tubes. There was no glue (legally binding or otherwise) to discourage me from adjusting the switch.

It was an educated guess, but I stand corrected, and will take you advice and call a professional before I operate the unit.
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Old 01-16-2012, 11:10 AM   #23
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Water under the bridge
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Old 01-16-2012, 11:14 AM   #24
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Quote:
Originally Posted by jones814 View Post
I have read numerous posting on the web (1 technical alert from the manufacturer) that the switch is prone to failure. I felt forceful air movement at the intake and exhaust outside. I knew the pipes were clear. I could feel significant suction on the blower side of the differential switch. I could see the flames going into the burner tubes. There was no glue (legally binding or otherwise) to discourage me from adjusting the switch.

It was an educated guess, but I stand corrected, and will take you advice and call a professional before I operate the unit.

You got the right information by coming here. And I am sure you've gained some valuable insight into how hazardous furnaces be. That by it self is 'nuff said
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Old 01-16-2012, 11:24 AM   #25
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Strange pressure switch problem


usually they put blue locktite glue or clear glue on the threads to prevent tampering but every manufacturer does what they want. nonetheless "alls well that ends well" and these posts are educational and your boo boo may save someone else's life if they read about it.

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