First post, so apologies for rambling! 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 kitchen has the same problem, but it doesn't go cold quite as fast. 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?
Also, 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 last thing, when the hot water runs cold, if we turn the tap/faucet down to a slow stream, the hot water remains pretty hot.
Sorry for rambling, but just wondered if anybody else out there had any ideas as to what might be causing this?
Another plumber suggested it could be the check valve in the faucets, however, we are having the same problem with the kitchen sink (hot then cold..although it isn't quite as bad and the kitchen is on the floor below the top floor).
`Sounds like a cross connection.Try shutting the valves off under each fixture. You only need to shut off one side, hot or cold, doesn't matter. Do one fixture at a time until you find the culprit. I do not believe you had a plumber come out to look at this and they could not figure it out, very simple stuff...good luck