Is this at risk of freezing?

trivetman · October 20

I've been running a recirculating hot water loop using one of those crossover valves which uses the cold line for the return. I am in the process of rebuilding a third floor closet and realize I've got access to a space next to the chimney where I can probably fish a line of pex through to the basement to be a dedicated return line.

Only hesitation is I don't know how cold this space might get. it's a hot water recirculating line, but there's always power outages and other edge cases to consider. My gut tells me it's far enough from the exterior wall not to be a freeze risk (as long as the house heat is working!), but I'm not 100% sure. I'm also realizing we have some existing water lines running from basement to second floor in essentially the same spot two floors down and which have never been a problem, but I didn't put those in so never questioned them. House is a 1900 build without any insulation against the stone exterior.

Here's a top view cross-section of the space Dimensions are approximate. Would you put a water line here for a client? Region is Philadelphia area.

mattmia2 · October 20

unless there is a significant draft in from the outside(which is certainly a possibility in that chase) that is far enough in to not freeze unless you've lost heat for probably a day or 2 or more

hot_rod · October 20

you will want to insulate the line to limit the heatloss if that is a cold space. Running recirc lines in cold spaces will cost more DHW fuel.

mattmia2 · October 20

it essentially makes all of the hot water lines in the loop part of the tank

Intplm. · October 20

You should be fine there. Just insulate the area.

pecmsg · October 20

https://forum.heatinghelp.com/discussion/comment/1868524#Comment_1868524

Key word………….Should

EdTheHeaterMan · October 20

I agree with @hot_rod & @mattmia2 sbout adding some pipe insulation. I also want to add

For the Philadelphia Fans.

JAdams · 10:52AM

Use PEX tubing for the recirc line and insulate it well past the possible freezing point. If you wanted to take added protection, you could also run the insulated recirc pipe through a conduit, but long enough so the cold air can't penetrate through the ends. I live in an area where temps get well below zero and there is always a breeze. Also, remember that Hot water will freeze before cold water, so protecting it from a cool breeze should be taken.

4Johnpipe · 10:57AM

I would recommend insulating a hot water return line regardless of location. That said can you access the area above that closet or chase so you can seal off any potential down draft? That would be helpful…

Jack Getkin · 11:51AM

I agree the line should be insulated. You should also know factory insulated PEX tubing is available for purchase and use. It is more costly than uninsulated PEX but the insulation will be on the tube as you install it. It's a one and done operation.

Is this at risk of freezing?

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