No cold water when cold outside - pipe or cartridge?

[miketp]

When it gets cold outside, no cold water comes out of one of my showers. When this occurs, when setting the water to cold, sometimes no water comes out, and other times lukewarm water comes out. The sink faucet in the same bathroom works without an issue.

Is this likely to be a pipe that's freezing or could it potentially be a cartridge issue? If pipe freezing, what's the best way to insulate a pipe that's already installed without demo'ing the wall?

 

[Terry]

What decade was the home built in?
Insulation was considered a new thing in 50/60's and some walls had none.

 

[Sponsor]

 

[miketp]

1920's and it's on an exterior wall, so I suspect freezing but I don't know why it would sometimes be lukewarm and I also thought that usually the hot water pipe freezes first.

 

[Terry]

The hot lines tend to freeze first, but often it's a matter of placement and air movement.
If ther pipe was frozen, I wouldn't expect any water from it until it thawed. If the wall is open inside, you might consider foaming it. I prefer insulation on the cold side of the pipe and none on the warm side.

 

[hj]

quote;
I prefer insulation on the cold side of the pipe and none on the warm side.

??????????????Why?

 

[Reach4]

quote;
I prefer insulation on the cold side of the pipe and none on the warm side.

??????????????Why?

I expect it is to allow the pipes to be warmed by the inside heat.

 

[Terry]

I expect it is to allow the pipes to be warmed by the inside heat.

Yes.
I have done a lot of freeze repairs over the years. I know what has worked, and what hasn't worked.
UPC codes allows pipe with foam insulation in an unheated spaced. It still freezes.

I have done piping all ways that they "can" be done. It's very important that the pipe is kept warm somehow. If you can allow heat from the interior of the home to get to the pipe, that's a BIG help.
Sometimes the mere act of putting insulation on the pipe, preventing that warmth, is the exact wrong thing to do. In the real world.
Been there done that. Been there done that. Been there done that. Been there done that. Yep!

 

[miketp]

So the water's still lukewarm when set to cold. When I turn the handle from hot to cold I feel cold water for a second and then only warm water comes out. Would that point more to the thermostatic cartridge being bad rather than a frozen pipe? If frozen, would something like great stuff gap filler work for spray foam insulation?

 

[Terry]

Sounds like a bad cartridge if you're getting warm out the cold side.

The great stuff in cans won't do the entire wall. It just goes a little way. And NEVER use that stuff without gloves. It bonds to your skin.