Noisy Baseboard Heaters

[Sharpie]

I have a customer calling me about electric baseboard heaters that are humming while they're on. She also says that it constantly makes those metal contracting/expanding popping noises.

In my experience, when a baseboard heater starts up it some times hums briefly, and also "pops" from expansion/contraction. But not the whole time it's running.

Have any of you found this before? Does it sound like a problem to you?

I just want to have a game plan before I go to their house.

The installation is probably 20 years old.

Thanks,

 

[Dennis Alwon]

Not sure why it is constantly humming but metal will pop during the expansion and contraction as you say. Is this happening to one unit or all the units. You did use the plural for heaters.

It would be odd that this never happened before and they all are doing it. Are they all on one circuit?

 

[Bobhook149]

I installed some 240v heaters the other day and the same thing....hummmmmmmmm. maybe it is some metal vibrating back and forth with the magnetic field?

 

[PetrosA]

We recently swapped out a whole house worth of electric baseboard heaters for new fin types. The 8 footers we put in all had some hum with some being so bad we had to replace them (one in the master bed was so loud you could hear it out in the hallway). On a few, we found that the contacts in the basement were bad and voltage was less than good and once the contacts were replaced, the humming got more tolerable. Do the ones you're looking at have contacts?

 

[Sharpie]

I don't know what these contacts are that you are talking about. I haven't been there yet, but I would assume that they are either wall mounted or in-unit t-stat controlled.

 

[ron]

A response to a similar question on a home repair website

There will always be a little bit of metal expansion noise when a baseboard heater goes quickly from totally cold to maximum hot ...... but it can be minimised if the grommets or plastic shields are in place between the heating element and the metal that it sits on. Making sure that these are in place and that the heating element moves freely will seriously reduce the noise.

Having said that .... perhaps the problem may actually be caused by the thermostat.

Recent electronic thermostat developments have actually totally eliminated this noise.
Old style thermostats go on ..... stay on a while then go off ...... then stay off a while. This allows the element to swing from room temperature to very hot and back constantly. It also makes baseboard heaters the least comfortable of all heating systems.

The electronic thermostats .... set-back or otherwise .... have changed that. The better of these devices actually check the temperature of the air every 3 seconds or so ...... and by proportional control modulates the outpiut.

They are turning the baseboard on or off .... or leaving it on ...... or leaving it off .... every 3 seconds. The effect of this is ..... it doesn't get hot .... it just gets warm. If you do this constantly you could maintain any temperature you want and it never gets either cold or hot.
So under normal circumstances the electronic thermostat causes the baseboard electric heater to stay warm ..... just the temperature necessary to keep the room at the set temperature.
If it gets colder outside it will stay on a little more to maintain that temperature .... it will be slightly warmer but still constant.

This process not only saves a lot of energy and keeps the room more comfortable .... it eliminates that expansion and contraction ping in electric heaters.

The same heaters ..... with a better control and quiter as well.

 

[PetrosA]

I don't know what these contacts are that you are talking about. I haven't been there yet, but I would assume that they are either wall mounted or in-unit t-stat controlled.

Some houses with all electric baseboard heat will have T-stats controlling contacts for rooms/zones with large numbers of heaters. It allows you to use a 15A circuit to a SP T-stat to control up to 30A of heating. They are generally mounted near the main panel or near a main heating panel in a trough, depending on the size of the house and amount of heating installed. The ones I've seen are in boxes similar to a deep 1900 box. the T-stat is terminated in the box itself, while the heating lines come into a trough that the contact is attached to. The contacts are time delay, which is one way to check for their presence. If you turn the T-stat up and the heat comes on a minute or so later, you have contacts.

 

[Sharpie]

Thanks Peter. That makes sense.