Frozen pipe, air in line or circulator not working?

336mlk

My oil boiler system has 4 zones each zone has it's own circulator pumps. I had an issue the day prior where we had no heat just my fire place. Just so happened it was going to be the coldest day of the year in NJ. So the stats were turned off for about 24 hours. My house is 3,000 square feet and certain zones have better insulation than others. This is a new house and I never considered that the pipes might freeze.

When the issue was resolved the next day I cranked up the stats in all 4 areas. One of the zones is getting no heat whatsoever in the pipes. The stat was reading under 50 degrees in the room so I assumed maybe something was frozen.

This is a new house so I don't know where every thing travels along but my wife and I did our best with hair dryers and space heaters trying to see if we could find the frozen spot.

I wasn't sure if it was frozen pipe or not. One other thing I tried as a test was I could feel that the water was hot just below the zone circulator pump where it is connected closely to the main loop and even about a foot past the pump there was some transient heat. I then put my hand about another foot further away where it wasn't hot and I told my wife to turn up the stat. My question is if there is ice blockage say 30 feet down, should I still have felt the heated water at least move the extra 12 inches so that I would feel the heat. My theory was if I felt the heat then I know that the pump is at least working. Needless to say when she turned on the stat I saw the light come on in the control box indicating that the thermostat kicked in but I still did not feel the heat reach my hand, so I was back to is it ice or is it a pump that just died. I am reluctant to think it is air in the line because it was just working 24 hours earlier, but I am not sure. Well if it is a frozen line I tend to think it is frozen somewhere that I could not reach maybe in some crawl space I haven't found so the only recourse is to wait until Tuesday since the temp gets above freezing. Anyone have any suggestions.

Thanks

Jamie Hall

It may well be a frozen line, and if it is you wouldn't feel any heat in it beyond a very short distance as the hot water wouldn't be able to get in there.

Two thoughts.

First, it is possible to damage the pump by running it against a frozen line. Do it to test, perhaps, but limit the time it runs to a couple of minutes, maximum.

Second, if it really is a frozen line, it may also be a burst line. I would very strongly suggest that you close the water feed valve to your boiler until you either find the problem or until you can verify that it isn't blocked any more -- otherwise, you may have quite a flood on your hands...