Electric furnace not heating fully?

[Splinter]

Electric furnace is struggling to keep temp. Air coming from the duct is cool-lukewarm. Rheem unit. Air filter is clean, coil element in the duct is clean.

There are two circuit breakers on the unit. CB1 powers the brains and 1/3 of the heating elements. CB2 looks to just power 2/3 of the heating elements. (The furnace will run with only CB1 on, but not vice versa).

I am trying to find my multimeter to check the breaker, but also noticed that there is some kind of old moisture or a spot of some sort at the base of this module that the CB2 element wires attach to. Is that normal or possibly a sign that the part may be bad?

 

[larry4406]

1. it’s cold as hell right now so heat pump performance is reduced.

2. the heat pumps I have experience with have (3) double pole 240V breakers. One for inside air handler, one for outside unit, and one for the Optional internal heat pack (resistance heat like toaster coils).

3. perhaps your installation is missing the optional heat pack backup heat unit?

 

[PoorUB]

Electric furnace is struggling to keep temp. Air coming from the duct is cool-lukewarm. Rheem unit. Air filter is clean, coil element in the duct is clean.

There are two circuit breakers on the unit. CB1 powers the brains and 1/3 of the heating elements. CB2 looks to just power 2/3 of the heating elements. (The furnace will run with only CB1 on, but not vice versa).

I am trying to find my multimeter to check the breaker, but also noticed that there is some kind of old moisture or a spot of some sort at the base of this module that the CB2 element wires attach to. Is that normal or possibly a sign that the part may be bad?

That little black controller is a sequencer, sort of a time delay relay to bring on the heat. It looks ok to me as when the fail they often fail catastrophically, but it could still be bad. The rust on the mount doesn't bother me.

On the other hand Rheem sequencers seem to fail often. I worked for a company that sold Ruud, sister company of Rheem and it seemed ever wither we were changing sequencers that we had changed the winter before.

Really, the best thing to check this is a clamp on amp meter. After the unit has been on for a couple minutes the upper and middle wires should have maybe be 20 amps each, maybe a bit less not knowing the size of the heat strips.

Are you certain it is calling for electric backup? The thermostat could have failed too.

 

[Bert_]

Yup^ amp clamp is the quickest way to test.

Typically each element will be 5 KW and should pull around 20 amps. The op appears to have three elements which would be 15 KW total.

 

[fitter30]

Need a volt meter and amp clamp would help also. Each element has a high temp limit which is the black disk with the metal tap going left terminal. From the right termial to to the tab is the element. Each element is straight across. With power on and thermostat calling for heat each element should read 240 vac from right termial to limit wire. No power bottom two termials of sequencer should have 24 volts if it does bad sequencer. Can buy them from amazon or ebay.

 

[mikedodge]

Usually its those sequencers that fail. We've also had a heating element itself go bad and the round limit switch you see attached to the heater can go bad too but not as common.
If you use a clamp amp meter when its running and find one of the elements isn't working you can then check the sequencers for voltage to see if there getting power and if power is passing through them.

 

[ambenz]

I've seen those over limit snap switches also go bad and keep the element from powering up.
Clamp amp meter and a multimeter...trace out when the voltage fails to be present.