Frozen hydronic loop?

[Backglass]

Hey all.

I woke up this morning to no heat on my ground floor. I have a two zone system with an older weil-mcclain boiler. The zone upstairs is working fine. I also had a sink freeze up in the back of the house, so I think that is also the problem with my heat. The bathroom was not badly frozen...I just put a kerosene heater in the bathroom for 30 minutes and the water started flowing...no broken pipes either (yay!).

Now, I assume the loop is froze as well, but I cant seem to find where. There are many places where the pipes go through the wall and I have no access. I spent several hours on my belly in the crawlspace with a hairdryer heating as much of the loop as I could find, but to no avail. I am 90% sure it's frozen, as I can open the drain spigot on the loop and no significant water comes out (other than what gravity pulls out).

I am stumped. I was really hoping to not have to call in the cavalry, but I guess I may have to call a plumber/HVAC guy. I have read online about these electric pipe thawing machines that look like large battery chargers w/jumper clamps. Anyone have any experience with these? I assume they use electricity to heat the pipe.

Now, I also assum that it isn't the circulator pump (Taco) as even if the pump was froze-up, water would still exit the drain spigot due to the system pressure and fill valve (which it does not). Correct?

Any advice is very much appreciated!

Thanks!

[rmelo99]

How but getting the temp of the crawlspace up with one of those salamander kerosene,diesel heaters.

Just curious if the heat for the downstairs loop is/was working. Moving/circulating water tends to not freeze as much or quick as water not flowing in pipes.

[nhmaster]

The pipe thawing machines work very well and fast but they really need to be used by a professional as there is a risk of burning the house down if you don't know what you are doing.

[Backglass]

How but getting the temp of the crawlspace up with one of those salamander kerosene,diesel heaters.

Just curious if the heat for the downstairs loop is/was working. Moving/circulating water tends to not freeze as much or quick as water not flowing in pipes.

Yeah, that's what I have been trying to do, but no luck. I can't seem to find where the pipe is frozen. The downstairs loop was working, but we had freakish low temps that night (-7.8!) and we were cranking the wood stove so it wasnt cycling as often.

Things have warmed up, but not warm enough. :-(

[Backglass]

Update: On day 2, we finally found the frozen section deep in the crawlspace and hidden behind a bunch of insulation. Hit it with a hairdryer and in less than 3 minutes water started gushing out the loop drain spigot! Purged the air, opened the loop and voila! Heat! It's a VERY good thing the pipe didn't burst as this would involve major house surgery to repair.

Thanks all!