Electric baseboard not heating fully

Divelucaya said:

Yes, 120V from white to ground and black to ground. All breakers for my heaters are 240V. I did not check from white-black or black-black. The fact that the heater used to easily be able to heat the room to 70 degrees but now cannot get it above 62 degrees, and that before the housing would get hot to the touch, but now I can touch the element fins and find them only warm has me thinking the heater is only working at half capacity. But I am not sure how a 220/240V heater can go to 120V heater.

I am wondering if I should bypass the cutoff and wire the black supply to the black line from the element. Isn't that how 220/240V heaters work - 120V out of phase to both ends of the element?

Click to expand...

Yes.

I tend to be methodical, and would check for 240 at the breaker, then into the thermostat, then out of the thermostat, then at the connection at the heater. If you have 240 at all locations, the heater element is probably gone.

If there is an open or break between the breaker and the heater connection, you could be reading the same 120v phase, one from the breaker side, and the other returning back through the heater element.

I would also check the resistance of the heater element and hopefully you have an identical one to compare to.

Lets say the element shorted out, and caused a poor connection somewhere along the way to melt open, or one side of the double pole breaker to open, or possibly a melted contact in the thermostat.

You seem to have some knowledge, so be safe and do some tracing. Be aware that if there is an open somewhere and there also a short somewhere, disturbing / moving the wiring connections could reconnect them suddenly and unexpectedly.

I would kill the breaker and cap the wires at the heater connection, then close the breaker and check that way.

Also, if my theory is correct, it could have simply been a poor connection that just gave out (with no short).

Have you measured 240 volts between the two feed wires (black and white) coming out of the wall? With the heater only lukewarm, is is uniformly warm over its entire length of is one end somewhat warmer than the other?

One thing that can help is an ammeter. The clamp on kind is good enough here and convenient to use here. At 240 volts and 935 watts the heater draws 3.9 amps. (watts equals volts times amperes) At 240 volts and significanly less amps we have a bad heating element; there are multiple sub-elements running the length inside some of which are burned out.

Some multimeters have an amperes function but you must be very careful not to exceed the rating, sometimes only two amps. If you do exceed the rating you can destroy all of the functions of the meter. You break the circuit (here, undo one of the wire nuts) and touch the meter probes to the two wire ends respectively i.e. connect the meter in series with the load. Even if the load normally uses just one half amp you will get a spark when touching the probes and another spark when you withdraw the probes.

A caution bears repeating; do not measure from hot to hot or from hot to neutral using the amperes function; that will cause a short circuit that blows out the meter. One of the wires you touch the probes of an ammeter to must go to a load (light, appliance, etc.)

My multimeter has a separate port for amps. It says 10A For 30 sec MAX every 15 min. FUSED (there is a fuse for each "red" port). I wish my organization was better because I have no idea where the multimeter manual is. Story of my life.

Please explain in a little more detail how to test the amps on the heater. Do I keep the load on both ends of the element (white on left side. black on right side), remove one of the loads (white or black), or remove both (in which I would have to assume the multimeter needs to supply its own load)? Option 1 sounds like what you cautioned about, testing from hot to hot so I don't believe this is what you meant. Option 3 doesn't seem right either.

I have done a lot of my own electrical, along with plumbing, automotive, etc., sort a jack of all trades but a master of none. So sorry if I seem a little confused about this, going through a lot of personal crap too. I use the multimeter a lot for voltage checks and some ohm checks, but have never used the ammeter function. Like I said, having the manual would be nice. Time to search the Internet, although I find free Craftsman manuals harder to find than a lot of other manufacturers.

Thanks again all for your help.

This needs to be done hot, if you contact the two wires you will get a very nasty shock.

Set your meter back up for voltage reading first!

I leave the wirenuts on and stick the probes in.

Just be aware, if they are not on tight they could pop off, just be ready if it happens.

Use of multimeter for amperes (current) measurements:

For this heater, observe the two wires coming out of the wall. One is ultimately connected to one end of the heater element. The other is connected to the cutoff device which in turn is ultimately connected to the other end of the heater. One "loop".

Turn off the power. Remove one of the wire nuts holding one of the wires that goes directly to the heater element (the load). Now you have two loose wire ends. Turn the power back on and then touch one probe to each of these wire ends. What you have now is the power coming in and going to the cutoff device, then through the meter, then through the heater element, then back out the other wire into the wall. Again, one loop and the meter is now part of the loop.

If you don't feel comfortable holding the probes with the power on, you can (with the power still off) wire nut each probe to one of the loose wires. Then turn the power on and come back and read the meter. Turn the power off again and then disconnect the meter and reconnect the two wire ends with the wire nut.

It is a good idea to get in the habit of not leaving the multimeter in the amperes or ohms (continuity; resistance) positions after completing a test.

Sticking the meter probes into two different wire nuts of an intact circuit will not give a useful amperes reading and also increases the chances of making a mistake and blowing out the meter. To do amperes measurements with a multimeter you must break the circuit (such as undoing a wire nut as described above) and then using the meter to re-complete the circuit for a few moments using the two probes.

Using a clamp on ammeter you keep the circuit intact and put the ammeter jaws on any wire without cutting the insulation. This measures the amperes going through that particular wire. For this heater, the various elements -- wires, cutoff device, heating element, are all in a single continuous loop. The number of amperes going through any part of that loop is the same so it does not matter which wire you put the clamp on ammeter on or which wire nut you undo to do the measurement with a multimeter.

Sorry, Marc, but the resistance of the heating element varies with its temperature. The resistance would be 61 ohms at full operating temperature, but much less when the heater is cold (was off for a period of time).

If per chance the heater has multiple sub elements running the length of the element and some are burned out, it will still have a non-infinite resistance.

There is some formula that relates resistance to temperature but I don't know what it is and it is different for:
1. the kind of metal making up the heating element innards (or sub-elements),
2. whether there is more than one sub-element.

So I am unable to draw any conclusions (other than its being burned out completely; infinite resistance) from measuring the resistance of the element unless I have a second heater of the same kind to compare it with.

(for those eavesdropping) Don't forget, when doing continuity or ohms measurements, unhook or remove everything from at least one of the two wires or terminals to which you will touch the meter probes. "Continuity" is a relative term that usually needs some experience to interpret. For example in some cases continuity means almost no resistance or almost zero ohms and many ohms means lack of continuity. In other cases lack of continuity means infinite ohms and some, even many, ohms means you have continuity.

Hello all,

Okay so I understood that the multimeter needed to be "wired" inline. Check. Well, as I mentioned earlier, personal issues play on my mind, and today was not a good day to be trying to troubleshoot the heater. I turned off power to heater, wire capped the multimeter probes to the black load and the wire to the element opposite white load (I just left the cutoff bypassed). Connected the red probe to the 10A port and, sigh, connected the black probe to the wrong port (not the COM port). Turned the heater power on, turned the dial to 10A and got a reading that settled at 0.11. I then realized I had the wrong port and turned off heater and multimeter and corrected the port error. Turned power back on and the multimeter to 10A and got 0.00. Turned off power and put wires all back together, to include the cutoff. Was going to call it quits for now, but decided I would check the functionality of the multimeter and check between load wires. I did this at the wire caps and got 0.00 and realized the red probe was still in the 10A port. Should have definitely quit at this point as my frame of mind was in bad shape. Switched ports and tried again. Well, some success - 244.7V between loads. Shut off the heater and multimeter and left the room. I ended up going back and doing a check of one more thing I won't even mention here, one that may have taken out the multimeter, or hopefully, just the multimeter fuse.

I thank you for all your help. I am where I am just going to assume the element is bad. As with any type of job, it is a bad idea to try something when you just can't maintain full concentration. I know the dangers of electricity (I used to work at a nuke plant and my brother was a lead linesman and a member of IBEW) so at least I was able to maintain a degree of safety and not try to do anything with hot lines. I will end it here with just a side note to any DIY's out there who may read this. Heed the warnings that many responders will give you, whether it be for electrical, plumbing, or any other trade related work. Unless you feel 100% confident and can maintain concentration on what you are about to do - HIRE an expert, licensed tradesman, trained worker, or anyone who gets normally gets paid for the task you want to accomplish.

Thank you all again.

TTW said:

Hello Marc,

I would love a copy of that chart so if you would please post it I would be thankful.

Merci Beaucoup

Click to expand...

Pas de Problem .,,

Voila le chart for you and the other readers.




This should help ya to memorized or refresher it.

Merci,
Marc

Buy a portable plug in electric heater for your son's bedroom. Likely cost about $25. Any portable electric heater has approximately the same energy efficiency as any baseboard electric heater.

You can do some simple tests to see what parts of the multimeter still work.

1. Using DC volts, does a 9 volt battery measure approximately 9 volts and an ordinary battery measure approximately 1-1/2 volts?
2. Using AC volts, do you still measure (approx) 120 volts hot to neutral on any circuit 240 volts hot to hot on a 240 volt circuit?
3. Using the ohms function, do you get zero ohms when you touch the probes to each other? (after using a calibration adjustment provided for this purpose)
4. Using the ohms function, do you measure at least a few ohms across the bottom and shell of a low wattage (7 to 25 watt) incandescent lamp?
5. You can probably think of other tests you can do. Be aware that plug in power supplies (wall warts, etc.) may deliver more than their rated voltage when measured at the loose output plug end, when not actually powering their devices. Also, an automotive electrical system usually measures in the 14 volt range when the engine (and alternator) are running. You can test the amperes function using a battery and an incandescent flashlight bulb, the latter typically draws from 1/4 to 1/2 amp. (Be sure that one probe is connected to the bulb and to nothing else otherwise an incorrect connection even in this test can blow out the meter.)