[cwinter]

I have electric baseboard heaters in my family room that have been giving me problems. Last year I replaced the thermostat when the heaters weren't cutting in and out properly and when I removed the thermostat I found that the wires had nearly fused together on the back. After replacing the thermostat the heat worked fine for a couple of months but now I have no heat. This time I suspect the heaters.

My question is how do I diagnose whether or not the heater is faulty?

[Frdbrkl]

Think of electric baseboard heaters as "toaster coils", as that's pretty much what they are by design, with some extra fins thrown on to dissipate heat more quickly.

KILL ALL POWER TO HEATER!

Check continuity through coils. If you have no continuity, the limit is open or the coil is bad. If they're EXTREMELY dirty, chances are that the limit has tripped open due to heat build up. Finding a limit for a baseboard heater-I've never tried. Usually when I get to them and the limit is tripped, they're ready for replacement (half the covers missing, half the coils bad, etc).

Also note-with electric heat of ANY kind, it's advisable to tighten ALL connections every few years. It appears something is pulling *waaaaaay* too many amps judging from the comments about "wires fusing together"-and that's not a good thing.

If you don't have an amp clamp to test this unit, I strongly recommend contacting an electrician (yup-they install them all the time) or a heating contractor. Don't call a plumbing company, even if it says "heating" on their name, as they are simply boiler installers and the vast majority won't be able to help you with electric heat.

[cwinter]

Thank-you for your input. I tested both heaters and they worked fine. The problem was in the wall thermostat it had burned out again. Since I bought the house 6 years ago I have replaced the thermostat twice for the same problem.

I decided it was time to consult a professional because as you said, there was obviously a problem with amperage. He gave me the following information which may be of use to other readers so I will pass it on:


Allow 10W of heater for every square foot of room space.

Each heating circuit should be designed to draw around 80% of the maximum breaker amperage. So for a 20A, 240V circuit he recommended that the heaters should draw around 16 - 18 A; certainly no more than 18A.

To calculate the amperage drawn on a circuit divide the heater wattage by the line voltage.


When I did that for the room in question it turned out that I had 5000W of heaters on a 240V circuit which meant that it was drawing nearly 21A through a thermostat designed for a maximum of 20A. Then I started wondering why the breaker wasn't tripping on the circuit. When I went to the panel and figured out which circuit it was on, I discovered that it was put on a 30A breaker! In Addition, while the heaters were gone we were using a 1000W portable electric heater on a 15A circuit. Occasionally my daughter would plug it in to the wrong receptacle with the TV, computer etc. plugged in at the same time and trip that breaker. When it tripped I discovered that the potlights over our cabinets in the kitchen would go out as well. I had a lot of confidence in the construction of my house but at this point I am doubting the quality of the electrical job.