Frozen Pipes

[secondcurve]

I need some advice on how to deal with a frozen forced hot water heating pipe. Last Thursday night I set the temperature in my family room zone to 60 degrees. The family room is over a two car garage that has a Modine heater in it that I had set at 50 degrees. Well as luck would have it, when the temperature plunged a pipe in the family room zone froze. At least that is what my oil burner repairmen determined and I have no reason to doubt him. He tried to free the freeze up by bringing the pressure in the boiler up but to no avail.

Since Friday I have had the modine heater in the garage set on 80 degrees and the other two zones on the first floor at 73 degrees. The temperature in the family room has gradually increased from 60 degrees to 68 degrees, but that zone remains frozen. My fear is that the pipe will break in the wall. That would be a nightmare! The problem I have is that all of the forced hot water pipes in the family room are buried behind finished walls. Is my only alternative to keep the adjacent heating zones set at high levels and pray the pipe doesn't break? Any advice would be much appreciated.

[ApS]

I'm completely unfamiliar with this kind of heating system, but if the suspect area is an outside wall, perhaps insulate the outside with a dark tarp, plywood, built-up snowbank, etc?

If it faces south, even better for the tarp idea—even adding an emergency coat of dark paint outside would be better than breaking into a wall.

[TomC]

to prevent future issues, have your plumber/heating guy fill the boiler and pipes with antifreeze. there is a type specially for this purpose. an anti-backflow valve (may already be present) will also be needed to keep the AF out of your domestic water system. very simple and not too expensive and then your problems are over.

as for thawing the current pipe out, I believe you are currently doing the right thing.

[Pineedles]

Step1
Frozen hydronic (hot-water) heating pipes present problems best addressed by a plumber. Your best bet in the meantime is to turn off the heating system's water supply, which will prevent a major flood in the event that a burst pipe thaws. Do not turn off the boiler if you have more than one heating zone on your thermostat, since another zone may be working.
Step2
Relieve any excess pressure in the system. Follow the same procedure you would to drain a waterlogged expansion tank: Shut the valve to the expansion tank. Attach a garden hose to the hose bib on the tank and extend the other end to a drain. Open the hose bib to drain the tank. Then close the hose bib and open the valve to the tank.

Looking at several sites they all say to avoid extreme heating sources such as a torch or other such devices. One site mentioned tenting the inside and if necessary the outside wall and tryng to create a "warm zone" in the enclosed area.

[brk-lnt]

Call a welder (assuming it's copper pipe). They can clamp the welding electrodes to either end of the run and run a current through it. The current flow heats the copper pipe evenly without the need for a flame. The water starts the flow and the rest of the ice melts away with the flow of warm water.

Should take about 30-45 minutes, and the welders are usually happy to have the extra business.

[secondcurve]

Folks:

I appreciate the suggestions. I have shut that zone down (both in and out) and turned off the blower. I have plumber coming in the morning with a tool that should help defrost the pipe as Brk-it suggested. I'll also ask about the antifreeze in the pipes that seems like a great idea. I'll let folks know how it turns out.

[secondcurve]

I guess sometimes you catch a break. I tried my heat again this afternoon and it worked!! Evidently the warmer outside temperatures in combination with my keeping the adjacent zones cranked up defrosted the blockage. Thanks again for all the advice.

[dpg]

I'm no expert by a long shot but one thing I do know is never put direct heat onto the frozen pipe like a hair dryer or something similiar. That's a way to burst a pipe for sure. Yup experience...

[ITD]

Originally Posted by dpg

I'm no expert by a long shot but one thing I do know is never put direct heat onto the frozen pipe like a hair dryer or something similiar. That's a way to burst a pipe for sure. Yup experience...

DPG, that pipe was probably already split, the damage occurs because water expands when it freezes, the ice forms a plug that lets go when you melt it.

I second the antifreeze suggestion, especially since you now know you can have a problem.

[trfour]

I used a torch to thaw a copper pipe at the camp on Paugus Bay that would freeze up when the temp. got down to below -15 degrees even with a heat tape on it until I re-plumed it higher off the dirt floor in the cellar. Never had a copper pipe split though.

Now, if you have PVC pipes, I would not recommend using a torch!

[robmac]

I would also suggest while you have the plumber there ask about insulation to prevent future freeze ups. It can get real ugly and expensive,as the old saying goes"pay me now or pay me later"

[SIKSUKR]

You did exactly the right thing short of the electic resistence mentioned by Brk.Here's the rub though.If this is the first time that you have had this zone freeze by turning down the temp than you have another thing to think about.You mentioned the pipes are located in the wall.This would make them closer to the outside cold air.In the time it took for your space to cool down to the set temp,that pipe froze.That's pretty fast which tells me that zone is doing a lot of heating to the outside as well as your house.It may well be worth your effort in fuel savings along with eliminating this potential problem to get at those pipes and either move them inside the heated space or insulate them.

[nightrider]

In this climate, avoid heating systems using water, especially seasonal homes. Forced hot air is the way to go.

[Kamper]

Originally Posted by secondcurve

... I tried my heat again this afternoon and it worked!! ...

Congratulations!

For future reference, there is a "wrap" you can get to thaw pipes. It has an electric heating element sewn into it. I've seen these used with good effect on regular water pipes. You can leave it on the pipe year-around but remember to unplug when not in use.

If you use a blow-torch on frozen pipes, apply the flame away from any joints to avoid melting the solder. Use a fire-proof back-stop when using a torch in any confined area. Just heat the pipe for a few minutes at a time and allow the water to "circulate." Have a fire extinguisher or water spray bottle available. When heating 'over-head' pipes, a tank of helium can come in handy.

You can also add a "heating chamber" to household pipes if you are susceptible to freezing. Basically this is a section of larger diameter pipe in the main line inside the house. Supposedly, this allows a larger reservoir of warm water to build up when heating with a torch. Although I've heard of this from several sources I've only seen it once. I wouldn't be surprised if that was just a repair using what was on hand then explained away as high-tech. That was a horizontal pipe but I'd think it would be more effective in a vertical piece.

And that's all I think I know about that...