Potential frozen pipes - strange behaviour

[GusPike]

Hi,

My bathroom is behaving strangely, and while it seems like frozen pipes (very cold day), I'd like to exhaust other options before taking drywall down.

Here is how I believe my water flow runs. Main water in branches off to bathroom sink, toilet, tub, then kitchen sink, then to the hot water tank. Hot water runs back in the opposite order - kitchen sink, bathroom sink, tub.

This morning, bathroom sink has cold water but no hot water (i.e., open tap, nothing at all comes out). Toilet still works and re-fills. Bathtub faucet does not provide any water at all, either hot or cold,. Bathtub faucet is one faucet for both water sources (i.e., I do not have separate hot and cold water faucets - it's one of those ones you pull out to turn on and then turn left or right to adjust the overall temperature).

Kitchen sink works fine with both temperatures.

Strange behaviour is I turn on the tub turned to cold (nothing happens), bathroom sink cold faucet (cold water in the sink, nothing in the tub) and then open the bathroom sink hot faucet (no hot water in the sink, still cold water in the sink, suddenly now have cold water in the tub!).

I close both taps in the sink, cold water continues to run in the tub. Turn tub all the way to hot, water flow stops. Turn back to cold, no flow at all. To get it restarted I have to open both the taps in the bathroom sink again.

What does this sound like to people? If it is frozen pipes, any idea where the "freeze" could be? As far as I know, cold water supply pipe does not run by any outside walls. Hot water supply pipe does follow an outside wall in the (very well insulated basement) before getting to the bathroom but after the kitchen sink. Both the hot and cold supply pipes in the basement were insulated as best possible before the drywall went up.

Any suggestions welcome - scared to call a plumber cause I don't want to open up any walls/ceiling if I can avoid it.

Thanks,
Gus

 

[Plbgbear]

I know you probably don't want to hear this but your best bet is to get a plumber out there and let him trouble shoot it.

 

[GusPike]

Thanks for the reply. Plumber diagnosed as frozen pipes and used a pipe thawer on the hot water pipe - water flow is back to normal. However, he did state that he was quite baffled as to the behaviour of the pipes (i.e., why a frozen hot water supply pipe would affect the cold water coming into the tub - unless of course the cold and hot water taps in the sink were turned on!), so if anyone has theories, I'm all ears

 

[havasu]

It sounds like your anti scold valve mixers have become affected by the freezing lines. Since the plumber did a temporary fix, did he provide recommendations as to what to do in the future?

 

[SlowDrip]

Havasu is correct, it sounds like your mixing valve isn't swapping over correctly, probably because it was damaged by the freeze. The first step would be to replace that (usually a free part under warranty)

You need to insulate those pipes ASAP before more serious damage occurs. I somehow doubt February is going to be very kind on us Ontarians.

 

[speedbump]

More years ago than I care to talk about, a customer in Michigan had no water at all in his house. He had a pump/tank in his basement, then a copper line that ran along a cement block wall in his heated basement. Temp in basement was above 70°. We looked around the basement at all the plumbing and noticed that when I walked by the area between two cement blocks, I could see a sliver of sunlight. It allowed cold air to blow through the crack onto the copper pipe and freeze it solid in an otherwise warm basement. Used a torch on about 6" of pipe and all was well again.

Just goes to show...

 

[GusPike]

Havasu is correct, it sounds like your mixing valve isn't swapping over correctly, probably because it was damaged by the freeze. The first step would be to replace that (usually a free part under warranty)

You need to insulate those pipes ASAP before more serious damage occurs. I somehow doubt February is going to be very kind on us Ontarians.

Would the mixing valve be in the faucet in the bathtub? Because the freeze (we're guessing) happened somewhere in the basement. Although I still don't understand how. The hot water line does run along the top of the foundation in the header space, but last year we insulated all of the walls and headers (to R-24 where there was space) and I put pipe insulation around both the hot and cold water supply pipes everywhere I could reach. The basement has never been this warm or comfortable.

Only prevention I can think of is to actually move the hot water pipe (a pain, since we've now finished the basement) or install a device that warms the pipes with current during the winter months...

sigh...

 

[SlowDrip]

Huh, not sure how I missed responding to this, sorry.

The mixing valve is located behind the handle of your shower. It is probable that small pieces of ice traveling through the line damaged it.

As speedbump's story shows, it doesn't take much uninsulated pipe to cause an issue. You can make most of your pipe R-10000 if you want, an elbow sitting against a cement wall is still going to freeze when it gets cold enough.