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Baseboard Heating

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Baseboard Heating Frozen Pipes

The Home Wizard app calculates your ideal home care program to avoid problems with your Baseboard Heating, but sometimes trouble can still occur. Here are answers to questions about baseboard heating frozen pipes.


the pipes in one of my base boards are frozen. How do I thaw them out?


Dear J.C.

The first step in thawing out the frozen baseboard water pipe in your home is to locate the main water shut-off valve for your house. It is typically locate just inside your house near where water supply first comes into your house. If you are on public water supply, then this valve will be right downstream from your water utility’s meter. Make sure you have clear access to this valve, and that it is not obstructed by boxes, storage materials, etc.

The reason you will want to locate this valve is that if during the thawing process of your frozen pipes, that the ice blockage turns out to be upstream of where the pipe may have cracked, then you will want to be able to shut off your main water supply ASAP.

The next step is locating all the locations where pipes have frozen. Go around your house and open up each faucet, flush each toilet, etc. If water does not come out (or just comes out in a dribble), then you likely have a frozen pipe located in the line coming to this faucet. Even if you have found one area of frozen pipe, it is a good idea to take an additional minute to check to see if there are other areas that have been affected by the same freeze.

The next step is to try to find the specific area in your baseboard piping where the frozen blockage is occurring. Sometimes the frozen area of the pipe will be frosted or have ice on it. If the situation is getting critical the pipe may be slightly bulged or look slightly cracked.

There are two kinds of situations that you might have to deal with: 1) the frozen pipe is exposed, where you can work on it; or 2) the frozen pipe is behind a wall.

If the frozen pipe is exposed, then there are several techniques that you can use to thaw it out. We recommend that you do NOT expose your pipe to anything hotter than you would put on your hand. Heating up a pipe too fast, for example using a torch, can actually cause the pipe to rupture from the steam that is produced and is potentially trapped between frozen sections of the pipe.

A couple of good choices for heating up your frozen pipe are:

- Hair dryer.
- Hot towels (just keep replacing them as they cool off).
- Space heater.
- Light bulbs, or better yet, a heat lamp.
- Well-grounded heating pad.

One trick you can use to speed up the process is to place tin foil or a cookie sheet behind the pipe to help reflect back the heat from your hair dryer, heat lamp etc., to the back side of your pipe.

If you find that you frozen pipe is behind a wall or ceiling, then you’ve got a little different problem on your hands. But you’ve got several options here:

- Place a space heater or fan near this section of your wall or ceiling, and allow warm air to circulate around this area.
- Use lamps or better yet, heat lamps to warm up this section (keep them back at least 8-18 inches from the surface).
- Turn up the heat in your house and wait (but if its cold outside and the frozen pipe is on an outside wall and inside of a cabinet, it may be a very long wait).

Hopefully this helps you with safely thawing out your frozen baseboard heating pipe.



We have a baseboard heating system in one room powered by a natural gas boiler. Since we moved into the house a couple years ago, we have not used the heating system to heat that room, since it is a sun room and we just don't use it in the wintertime. However, a month ago, we did some maintenance on the exhaust pipes from our main furnace and this other boiler, and turned off the pilot light while we did the repairs. Since we didn't know any better, we left the pilot light on the baseboard heating system boiler turned off, thinking that since we didn't use it, we didn't need the pilot light. Once we got some cold winter temperatures, we had a pipe in that sun room baseboard system freeze and burst. A maintenance person came out and fixed the broken pipe and got the heating system turned on again. We now have the heat on in that room, but we were wondering why the pipes never froze in that room before? Since the pilot light was on before, did that keep the water circulating and keep it from freezing? If we wanted to turn off the heat to that room, can we keep the pilot light lit and avoid the pipes freezing?

Thanks for your answers!


Dear "Arizona":

Had you ever used the heating system in your sunroom? The reason I ask is that I'm wondering if the previous owners may have also not used the baseboard heating in the sunroom, and as such, may have drained the water out of the system. Then when your service person came out they may have filled the system back up with water. The combination of water in the system, plus very cold weather, plus the heating system turned off is a formula for having a pipe freeze and burst.

The pilot light and the water circulating through the pipes are two different things. The water doesn't circulate because of the pilot light, it circulates because the thermostat in the room says that the temperature is too low, so it signals to the boiler to turn on and the circulation pump to circulate the hot water through the baseboard radiators. And this it will continue until the thermostat says that the room is warm enough.

So if you are not going to be using the heating system in your sunroom, the safest thing to do is to completely drain the water out of the baseboard heating system for this room. You might also want to consider shutting off the natural gas supply to this boiler.

Hope this is helpful.


Hi, I recently bought a 135 year old home with hydronic baseboard heating. Apparently last winter it wasn't winterized properly so the pipes burst. All over the home I can see right next to the baseboards where the pipes have popped apart. Would this really have been caused just by pressure? Naturally I would assume that once pressure was released from one burst section it wouldn't continue to be pressurized in every other room. Will this be reasonably simply for someone to repair? Does the layout of these systems typically have long single sections of pipe inside the walls and then the joints are near the baseboard units, or might there be other joints inside the walls that could have burst? (Sorry so many questions) Thank you for your input.


Dear April:

Regarding your questions about a hot water baseboard heating system that had frozen and burst your piping in several areas:

Yes, the damage you describe could have all been done by the force of the pressure from water turning to ice. When water freezes it expands, and if there is no place for the freezing ice to expand to, it will burst even metal piping. If your pipes throughout your house were filled with water, then you could get pipes bursting in many locations, as the bursting frozen pipes would only release pressure in limited areas (since the pipes would be frozen solid between areas).

If the sections of burst piping are located inside of walls, yes, this could be difficult to repair.

And finally, even if the original plumber was able to use continuous pipe sections inside of all of your walls, you could still have the pipes bursting even between joints.

Hope this is helpful.


Hi. I own a property with a gas furnace and baseboard heat. A tentant called and complained that his room was cold. He said he blead the baseboard heater and air came out for awhile and then stopped. He never saw water. He also mentioned that he was away for awhile and he had the heat turned down and maybe the pipes to the heater were frozen. When I went over, we blead the baseboard in his room again and alot of air came out, then nothing. All the other heaters on the second floor (the floor his room is also on) were hot. Inspecting the furnace I noticed that I only have one recirc pump so I'm assuming it's all one zone. Also all supply and return pumps felt hot. Do you think the pipe is really frozen? What else can I do to to try and trouble shoot this problem?



Dear Dave:

If you only have one zone, and the baseboard heating pipe was frozen for one section of your baseboard radiators, then it would be blocking the circulation for the other sections as well. You mentioned that you only have one recirculation pump, but then you went on to say that the supply and return pumps (plural) felt hot.

Is it possible that you have more than one heating zone? One way to tell is if you have more than one thermostat.

If you do have more than one heating zone, then you need to turn off the thermostat for the zone where you suspect you have your frozen pipe, and shut off the water supply feeding this zone. If the frozen pipe has burst, now that your tenant is back and your place is heating back up from the other zones heating up, then you could have a flood when the frozen pipe warms up.

If your pipe has frozen inside the wall, then you will probably need to call a professional plumber who will need to open the wall, find the frozen area, defrost it, check for any cracks, repair the crack and test it.

Hope this is helpful.


So my husband and I noticed that the baseboard heat in our living room was not heating up. Its 20 degrees out and we're suspecting that the pipes within the walls near the windows and exterior walls might have froze. We touched the baseboard pipes near the interior rooms and it was room temperature while the pipes near the windows and exterior walls were freezing cold. Initially, we tried to bleed the system but no water came out which lead us to believe that the pipes must've froze. So I used a blow dryer and tried to heat up the areas of the pipe near the window where is visible. I then release the valve in the boiler again to see if any water would come out but it did not. So I'm assuming that there are still parts of the pipe that's frozen. With that said:

1) Should we leave the thermostate/heat on even though no heat/hot water is being circulated because of the frozen pipes or should we turn it off? If we leave it on, will that create more pressure on the pipes and cause it to crack more easily? And if the heat was left on, is it possible that it will help thaw out the pipes quicker or make things worst?
2) Since parts of the pipes are hidden behind walls, what is the best way to locate the frozen part?
3) What is the best way to thaw it out without knowing where the frozen area is?
4) We have a portable heater that is now turned on high but the temperature outside is just too cold for it to warm up the entire room. I doubt it will warm up the pipes from within the walls. With no heat throughout the night, I'm afraid that more of the pipe will freeze. What do you suggest to prevent the pipes to freeze further?

Thanks for all your help!


Dear 'Desperate':

It sounds like you've got a big problem on your hands, so I just
wanted to let you know that I am working on answering your question, and should have it finished in about 20 minutes, if you want to check your email again then.




Dear 'Desperate':

First, immediately shutoff the makeup water valve for your heating system. Hopefully your frozen baseboard heating pipe will not burst, but if it does, you do not want the burst pipe to be flooding your house.

Second, if you know which of your zones is the one that has the frozen section in it, then close the valves for this zone and drain out any water that you can (although it sounds like you've already tried to drain it).

Note: be sure to turn the room thermostat for this zone off or all the way down, so that it doesn't try to turn on the circulation pump for this zone, since there is no water flowing in it.

If you have other heating zones, leave your boiler/furnace on, and keep the rest of your heating zones turned on, so that they continue to heat the rest of your home.

Third, try to locate where the frozen pipe section is located. Typical locations are exterior walls especially walls that have a cabinet in front of them (like under a sink or kitchen cabinets). Or it could be behind a furniture cabinet that is up tight against an exterior wall. The reason is that the cabinet space prevents warm air from the room from circulating past the exterior wall to keep it warm. It sounds like you have areas of walls under your windows that maybe where the frozen pipe sections maybe located.

As it sounds like you are doing, use your hand to feel around the exterior wall to see which areas appear to be the coldest, and the likely spots where the frozen pipe sections could be located.

Next, once you've located the area of the exterior wall where you think the frozen pipe section may be located, here are some options for thawing out the pipe inside the wall:

- Place a space heater or fan near this section of your wall or ceiling, and allow warm air to circulate around this area.
- Use electric lamps or better yet, heat lamps, to warm up this section (keeping them back at least 8-18 inches from the surface of the wall).
- Use an electric hair dryer, which it sounds like you are doing now, to heat up this section of wall.
- Turn up the heat in your house and wait (but if its cold outside and the frozen pipe is on an outside wall and inside of a cabinet, it may be a very long wait). You had mentioned that you had a portable heater setup in the room, which is good. But if you have portable room fans which you can place in the room to circulate the warm air past the cold exterior walls, this will help a lot.

Do NOT try to heat your pipes to thaw them out with anything stronger than an electric hair dryer. Using a stronger heat source (such as a torch or propane heater) can cause the trapped water to boil and explode.

Now here's the hard decision, another thing that you can do, is that if you have a very good idea of where in the wall the frozen pipe section is located, you can cut a small hole in the wall so that you can get your electric hair dryer to blow inside of this wall (however, remember that the vertical studs for this wall are typically every 16" apart, so this limits the range that will be affected by the hair dryer.) If you can pull off the baseboard molding for this section of the wall, this could help make the repair easier later on. I know cutting these holes sounds like an extreme measure, but if the pipe bursts inside of the wall, then you are going to need to open up this wall anyway.

On the other hand, if for some reason the frozen section of pipe are not inside the walls, but rather, inside of the room, then in addition to the lamps, space heaters, fans, etc. mentioned above, then you can also use hot towels (just keep replacing them as they cool off) or a well-grounded heating pad. And one trick you can use to speed up the process is to place tin foil or a cookie sheet behind the pipe to help reflect back the heat from your hair dryer, heat lamp, etc., to the back side of your pipe.

One last thought, is that you should probably locate the main water shutoff valve for your entire house, and be sure that the pathway to it is not obstructed, just in case any of the other water pipes in your house get frozen and burst. This way you can quickly shut down the water supply and contain any flooding.

Hope this is helpful.


Thanks to your quick reply.

I was wondering how we can be sure that the frozen pipes are thoroughly thawed. I'm concerned that there might be areas where its still frozen when I tried bleeding the system or turn the heat back on.


Dear ‘Desperate’:

If you want to check to see if the pipes are clear of frozen water plugs before you put fresh water back into your system, depending on how your system is piped, you might be able to blow air in one end of your heating zone and see if air comes out of the other end. If all of the valves are open between the beginning and the end, and no air comes out, then you still have a blockage in the line. But your system would need to have a way for you to connect (temporarily with duct tape would be fine), say a hair dryer or the discharge of a shop vacuum, at one vent or drain valve of the zone you were trying to check, and then have a way to open a valve at the other end of the zone.

The other thought is that if you have felt all of the exposed pipes with your hand, and have warmed up the walls for a long enough time where the pipes are inside the walls, then hopefully this should have allowed enough thawing to take place.

Other than that, I can't really think of how you could test that there are no frozen blockages remaining.

Of course, you will want to watch and listen very closely both when you are thawing and re-introducing water back into your system to see if any of your pipes had split when the water froze, as these can begin spilling water.

Hope this is helpful. If you have other questions, don't hesitate to let us know.

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