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HELP!! New install of GMUH75-E3A - Main blower starts immediately on power up/ thermostat turn on. Burner never turns on/ignites. AC power is wired correctly and gas supply is connected. Switch is in the ON position.

Posted by gallingd on

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You need to find out if the problem is in the T-stat, T-stat wire or in the furnace you can do this in a few easy steps

 

Step 1- Unwire the low voltage from the furnace. Then turn the power back on and see if the blower comes on if it does then the problem is in the furnace and you will need to troubleshoot the furnace (see bottom of page for troubleshooting furnace) if it does not then proceed to step 2

 

Step 2- Wire the low voltage back up to the furnace (follow the wiring diagram below). And unwire the T-stat, make sure that no wires are touching each other, then turn the power back on to the furnace, if the blower starts then you have a short in the T-stat wire and you will need to pull a new wire. If it does not then proceed to step 3

 

Step 3- Turn the power back off at the furnace and wire the T-stat back up (follow the wiring diagram below). Turn the T-stat to auto heat 90 if the heat does not start but the blower just runs then you need to replace the T-stat.

 

 

troubleshooting furnace

 

http://www.hvac-for-beginners.com/furnace-troubleshooting.html

 

 

wiring diagram

 

 

 

 

HELP!! New install of GMUH75-E3A - controlltech.png

Posted on Nov 24, 2010

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