is there a general rule of thumb in regards to how often I should circulate hot water through my baseboards so i can avoid frozen pipe (every hour? a few times a day?). I have one pipe which has frozen in the past (outside wall). I recently added new foam insulation around that pipe and added some fiberglass insulation to help with any drafts that are getting in. I understand many factors come into play (ambient temp, insulation, etc), but was just curious. thanks.

mp

 

Depends on how cold it is really and the amount of draft/exposure the pipe has..

IMO either add antifreeze and wire the circ for constant circulation for the cold months...

Otherwise every situation is different...

 

I don't know of a rule of thumb. To start with, I'd error on the more frequent side - maybe briefly once an hour.

Is there a way you can set up the zone in question for temporary gravity flow? Another approach is a short section electric heat trace tape, but follow instructions of the manufacturer to avoid combustibles. Is the pipe accessible from the basement or where it enters the baseboard? If so, a portable electric heater or heat lamp might help - run it on the coldest nights.

Adding insulation around a pipe routed through an outside wall might help and it might not. It could deter heat from migrating from the heated wall to the pipe, which could make things worse. In general, water pipes should never be run through outside walls.

Steel pipe will plug, but seldom ruptures if frozen. Copper pipe will split longitudinally like a hot-dog bun ("rolls" to some you?), and when the pipe thaws, you will be flooded.

 

That's a tough call to make and so many variables that it's really impossible to give you a concrete answer.

Insulating a pipe in a cold cavity often doesn't achieve the desired result. If you've still got the cold air all around the pipe, eventually it will still freeze, maybe a bit more slowly, but it still will.

A better approach is to insulate the 'cold side' and leave the pipe exposed to the 'warm side'.

Fiberglas insulation won't stop drafts. For this you would need a spray or board foam insulation product to seal the air infiltration. Fiberglas really only works as designed when confined in a 'dead air' space where there are no drafts, such as a wall cavity.