Intertherm blower problem

[rickbrk]

Ihave an Intertherm E1EB-015HA It has burnt up 3 A/C relays so I put a heavy duty Mars relay in and fused the red wire on the 24v side of transformer. I narrowed the problem down to the blower motor. It has a FLA rated at 3amps and the motor at startup in drawing 4-5amps could this be the problem? Also when I put it back together and put the fan switch in the furnace to ON and the one on the T-Stat to Auto the blower will not come on when heating elements are hot BUT if I put the T-Stat to ON and the furnace switch to Auto it works perfectly. Did I wire something wrong or does it matter that it does this?

Thank You
Rick

[Robert]

Hi Rick,


What is amp draw after a couple minutes of run time ? The amps will be up some on start up.



Your t-stat controls the ON/AUTO functioning, so furnace fan switch needs to be set to auto.


Do you have the Fan ON/AUTO switch and a HEAT/OFF/COOL switch on front of a control box at furnace ?



Did you replace a 2 wire t-stat with a 4 wire t-stat ?


Thanks,
Robert

[rickbrk]

I replaced the 4 wire T-Stat with a 4 wire. There is no Heat/Off/Cool in the furnace, only at the T-Stat. I will test motor amps again and let it run for a min. on start up the motor starts out slow and makes a little noise kinda like it is working real hard, this will last for about 3-4 sec then it comes up to speed. The motor spins freely but hand and I recently oiled it. I not sure if it is normal the way it starts up.
Thanks

[Robert]

Hi,


Ok, you wouldn't have the Heat/Off/Cool at furnace unless you had a 2 wire t-stat.



With the motor spinning freely and having been oiled , IF it and the wheel is clean, I would replace the run capacitor.


It will cause those symptoms, is relatively cheap and would be required anyway if motor is bad.



You make sure all is clean, oiled, good run cap, spins freely, NOT HOT to the touch and make sure it is getting full voltage to motor.



Gas Furnace Motor = 120VAC


Electric Furnace Motor = 240VAC



IF ALL above is covered and ok, then suspect that motor is on its last leg.





Thanks,
Robert