Heating Elements Not All Glowing Orange

[dominator]

Hi All,
I have a Coleman electric furnace model # EB10B and after about 15 minutes of running I took off the duct at the furnace and looked at the electric coils and I noticed that only the first 2 rows had an orange glow to them. The other 4 rows did not glow at all. I then disconnected the blower and all of the rows (elements) immediately turned bright orange so I quickly plugged the blower back in. Not sure if the element is going bad or the sequencer or both, if any. I guess my question is should the entire element be glowing orange while the unit is running? Temperature at the outlet vent is 110 degrees with a temp of 65 degrees at the return.

Thank you for your help!

Johnny

[Robert]

Hi John,

Look at nameplate to get design temperature rise/temp. difference between return and supply.

Also see what the element amps should be.

Then test amp draw on each coil and get the return and supply temps and compare to what it should be.


Thanks,
Robert

[dominator]

Hi Robert,
Thank you for the fast reply. The nameplate stated the unit was capable of a maximum temp of 200 degrees. I could not find anywhere on the plate the temp difference between the supply and return. I will look again though because maybe I am missing it somewhere. It's a 34000 btu and the element capacity is 40 amps at 240 volts.

[Robert]

Hi,

Should have the temp. rise listed somewhere. Test each coil amp draw to see if it's working at full capacity.



Thanks,
Robert

[dominator]

I tested amp draw on all elements and all was fine so I decided to use an infrared thermometer and point them at each one of the coils to see what kind of heat each one was putting out on the coils surface. Strange thing is when there is no negative pressure all the coils temps at the surface was in the 500 degree range. However, when I partially closed off the output side with a vent, the left 2 rows of the coils temperature went to 600 degrees, the middle 2 rows went to 450 degrees and the right side 2 rows of the coils went to 250 degrees. It seems that negative pressure is having an effect on the coils heating output. Do you think it's the entire heating element going bad, the sequencer, or both? Or is this normal?

Thank you again for all your help!

Johnny

[Robert]

Hi Johnny,

From what you've stated, sounds like all is fine. Amps are normal, temps within range and everything working.



Thanks,
Robert

[dominator]

Hi Robert,
So it don't matter if some of the elements have lower output temps (First two elements at 600 degrees according to infrared thermometer and the rest of them in the 250-450 range). I just figured that all of the elements would have equal heat output with the supply vent intact? However when I place the supply vent on the unit, the middle 2 elements along with the right side elements significantly decrease in heat and the left 2 begin to glow a brighter orange and put out more heat.

Thanks again for the fast reply. I really appreciate your help!

Johnny

[Robert]

Hi Johnny,

What supply vent are you referring to and why are you doing this ? Was there something wrong with furnace performance ?


The only thing needed to know if elements are working is the amp draw and temp at closest supply register.

If anything is wrong, those readings will be off.


Thanks,
Robert