We are replacing an old cast iron tub in our upstairs bathroom. There was no cutoff valve for the tub (house built in 1962, nothing has been upgraded previously.) We turned off the main water to the house, removed the tub spout and showerhead, capped those pipes, and then turned the main house water back on.

We now have no hot water in the downstairs bathroom or adjacent kitchen. Upstairs bathroom sink still has hot water, so the water heater is working.

House is a split level ranch. Bathtub we are removing is upstairs. This bathtub shares half a wall with the lower bathroom on the main level.

What did we do wrong and how can we get hot water flowing back to the other bathroom?

Thank you for any advice!!

 

hi -

So in other words there is no water at all coming out of the hot in the downstairs bathroom or kitchen. If so sounds like when the hot water pressure was reduced to zero some debris was dislodged and moved and is blocking the hot water pipe going to the downstairs. So the blockage would be beyond where the hot to the upstairs and downstairs pipe branches.

But I'm no expert for sure. I think more knowledgeable people will be along.

 

Water does come out when we open the hot water tap downstairs, it’s just cold.

Its very perplexing to me how that’s happening.

 

So if now cold water comes out of the hot tap do you have hot water from the cold tap?

 

No, cold water comes out both sides.

 

Oh, that kind of problem rings a bell. I think there was a thread not too long ago that described the same type of problem. Unfortunately I can’t remember the solution.

I think it had something to do with the cold water crossing over into the hot water pipes.

I’m pretty sure it had something to do with the cold crossing over to the hot at the fixture.

I think lawrosa(Mike) a plumber explained how that can happen, but I’m really not sure. I guess that maybe that would be at the tub/shower valve if that were the case here. I don’t see how that could happen just by capping the shower head pipe and the tub spout pipe – but maybe it could. Could it be that the valve is not now set so the hot and cold are both OFF?

Don’t know what that would do however – maybe nothing.

The more knowledgeable people will weigh in hopefully. I might be going off on a tangent.


(just saw Pilot Dane weighed in. Didn't read that post yet)

 

Turn off upstairs tub hot and cold valves. The higher pressure cold water is forcing the lower pressure hot water back down the pipe, The first floor sink's hot water valve is the first outlet in the reverse direction.