Winter Time/New Construction/Freezing

Hey all,

I’m new here and have a question for those who may have first hand experience with the following:

So, it’s December and sub zero temperatures are expected.

You’ve just installed a new system and pressure tested with water.

The house is not yet insulated, no power, etc.

Now the system is drained and the boiler drain is open.

Problem is, there’s still standing water in the short, or sometimes several foot, drops to the heads.

Do you pull every head and drain or trust the open and drained system will tolerate freezing water expansion?

Theoretically the pipe should tolerate expanding water if there’s no pressure, but I’ve been told three versions from installers.

1: pull every head and allow them to drain.
2: pull all the low hanging heads with several feet of water above.
3. the system will be okay when drained and valve is open.

I’d prefer to err on the side of caution, but pulling 100+ heads in a big house, when it’s cold, doesn’t seem too appealing if it’s overkill.

Any feedback is appreciated.


Is your system dry-pipe?
The concern I have is that the standing water in the drops will freeze and thus obstruct the orifice for the water to flow. Expansion is also a problem, like you mentioned.

Would it be fesable to go back and pull every head and make sure the residual water is drained out? It’d be a royal pain but you really don’t want to run the risk of letting that water freeze as it could put strain on the pipe.

I think it’d be better to err on the side of caution if it’s feasable for you.