We recently moved into the top two floors of a brownstone building and have a problem with the hot water turning cold rather quickly. Turning on the hot tap (bath or sink on either floor) results in a steady stream of hot water for up to a minute, but then it turns warm pretty quickly. The problem is worse on the top floor.
We had a plumber take a look and he thinks the problem may stem from cross flow coming from the washer/dryer?
He tested the h/w heater which is in the basement and separate to the boiler, by feeling the pipe whilst having us run the hot water from upstairs. When the latter went cold, the h/w heater pipes were still hot. So, he thinks the h/w heater is not the problem.
One other thing, when the hot water runs cold, if we turn the tap/faucet down to a slow stream, the hot water remains pretty hot.
We finally managed to diagnose this by turning off the MAIN cold water line for all of the apartments and running the cold water faucet in the bathroom...bizarrely cold water was still coming through.
Thought this was odd, even though the cold water line had been turned off in the basement. So looking in the basement, we then noticed a seperate 3/4 inch pipe that we discovered fed our washer/dryer unit only.
The plumber told us that the hot water running cold problem was most likely due to faulty check valves on the washer.
Unfortunately, we can't turn of the 3/4 feed pipe in the basement as the valve is thread bare.
Now, if we want to get the valve on the washer fixed, do we need to get the 3/4 pipe fixed so it can be turned off? Or is that not necessary?
Does this diagnosis sound correct? Any help much appreciated for a newbie home owner.