Frozen pipes that can’t be thawed?

[Jeremy Bartlett]

Need some help with my 4plex in Alaska... just had a units windows replaced with new triple panes which are working great - keeping the unit insulated at 63 degrees with no heat in the unit when it’s -10 out.

Because of this, the unit isn’t calling for heat as often, and a section of piping in the baseboard heating froze, so now the whole unit isn’t getting heat. 

Plumbing company confirmed that the boiler is working perfectly (it’s less than a year old). I called a thawing company out and they said that a section of the piping is plastic so their machine didn’t work to thaw it out... I went and bought my tenants a couple of radiator heaters in the meantime to keep them warm...

So that leaves me with these questions:

1) how do I thaw these pipes to get my tenants heat ASAP?

2) how do I check to confirm the pipes didn’t burst when they’re behind a wall once they do thaw?

3) how do I prevent this from happening again without opening a wall?

Any advice would be welcome!