Mr. Heater will not Start


  #1  
Old 01-16-24, 09:01 AM
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Mr. Heater will not Start

I have a Mr. Heater Max 50,000 BTU garage heater that has been working for years until now. When the t-stat call for heat nothing happens except for the LED flashing 3 times. I understand it's the pressure switch and it sounds as if the pressure switch failed to close before CAB is energized. So, the question is: How do I repair this? Is it the electrical switch on the pressure switch bad, or is there another issue?

Thanks in advance for any and all help!
Bill
 
  #2  
Old 01-16-24, 10:45 AM
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Welcome to the forums.

Please post the model number for that heater.
There are too many different sub models.

If it has a pressure switch then it must have a draft inducer.
The draft inducer should be the first thing that starts on a call for heat.
 
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Old 01-16-24, 01:47 PM
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3 flashes - Pressure switch failed closed before CAB is energized or failed open after CAB is energized

If the pressure switch is stuck closed it will be a cheaper fix than inducer or board failure.
Unplug one of the 2 wires to the pressure switch to see if the inducer will run.

is the model a MHU50 ?

 
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Old 01-16-24, 03:24 PM
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Not needed.
 
 

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