Testing at the electrical units would be where I would start. Voltage availability and continuity of the heating coils. Probably need another technician if your post is correct.

You should get a larger temp rise than 81 degree with both HP running along with 10 KW heat strip.

While it is not unusual, these heat strip units can go bad. Any good tech should be able to determine that.

And just for info, each KW in a heat strip yields about 3400 BTUs of heat.
10 KW about 35 KBTUs; with the 5 KW another 17 KBTUs. You must have a large home.

IMO

Home is 1950 square feet 2 story (not including basement 3/4 full, 1/4 crawl). Built in 1979/80. I have good windows but insulation and air sealing is on my list of to-dos.

If a coil goes bad, would it draw any current smoothly? Seems to me it would arc or pull zero current.

Also, the tech wired all three heat terminals together. W1, w2, and w3 are directly wired together now. I am getting a better temp rise at the register but outdoor temp got to 35 today. Wiring the terminals together seems wrong. He thinks one coil works but one is bad. Needs to come back.

What do you think?

âÂÂThe 10 kW coil will pull 19.8 amps on each leg of the circuitâÂÂ

Seems to me that only the 5kW element is working, 19.8amps (âÂÂeach legâÂÂ) times 115V(x 2 âÂÂeach legâÂÂ) =4554Watts=~15.5MBtu. Simple OhmâÂÂs Law, W (watts) = I (amps) x E (volts).

Check fuses & breakers. Turn âÂÂOffâ power at breakers and measure resistance across elements as Bus Driver suggested. Also check continuity across thermal breakers.

Leave testing under live voltage to a tech if youâÂÂre not up to it!

IMO

SR

This post was edited by fsq4cw on Tue, Jan 7, 14 at 10:04

You need a different tech. A rookie should ace your job 10 times out of ten the first day he is alowed to leave the shop alone. If resistant heat strips were as complex as hvac work got ,monkeys could be trained as techs.