Friday, December 9, 2022


Why is no water coming out of hot water faucet?


Dear Gary,
The 10-gallon water heater in my Holiday Rambler is still producing hot water but there is nothing coming out of the faucets. It is as if there is no water pressure, but there is no leak evident. When I turn the bypass valve to the “off” position, I noticed that water is still flowing into the water heater because I pulled the plastic drain plug. Either way, the water was flowing into the heater and draining out the drain hole. If the valve is bad would this be the answer as to why there is no pressure coming out of the faucet? —Kevin

Dear Kevin,
It sure sounds like you indeed have a faulty valve or two in that bypass system. I’m going to guess they are plastic valves, which seemingly have issues with the constant exposure to the heated water. Somehow, either the plastic body or the valve portion warps over time and gets stuck in the closed (or partially open) position. I’d toss those plastic valves and install a set of brass valves in their place. I’ll double my wager that all will be well after they are replaced.

There may also be a one-way check valve or backflow preventer positioned at the hot outlet of the water heater. A faulty check valve at the hot outlet could also reduce, minimize or prevent adequate pressure and flow from reaching the hot faucets. Some water heaters have a check valve located at the cold water inlet to the heater, but since you’re able to fill the heater and see it draining, a check valve at this location is probably still viable. But like the bypass valves, if those check valves are made of plastic, I’d replace them with brass valves.

gary-736Read more from Gary Bunzer at the See Gary’s videos about RV repair and maintenance.



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1 year ago

I had the same problem, it was the check valve,O-ring failed, I gutted it for now
2 years ago

My hot side of the kitchen faucet has no flow. Other faucets work fine. Replaced kitchen faucet – same problem. Can’f find any shutoff or bypass valves

jack roderick
2 years ago

I have a 2018 Airstream. The outlet from my hot water tank goes through a mixer valve, and they are prone to malfunction. When they fail, it shuts off the hot water output. The purpose of the mixer valve allows the water heater to heat the water to a higher temperature, and then mix the output with cold water for a longer-lasting hot water output. It works similarly to an anti-scald valve in a residential home shower.

Tom Herd
2 years ago

Do you have an outside faucet, such as a shower hook-up? If so, check to see that it is fully closed (both sides of the faucet). Even though there may not be any water coming out the faucet, for example if you have a sprayer on the end of the hose that is closed, the system will still allow your hot and cold to mix, at the outside faucet. You will not have hot water at the inside faucets due to the mixing at the outside faucet.

This is an easy problem to overlook, while you go in search of a bad valve, or some other problem.

Cari Gregory
2 years ago

Hi Gary I am living in a 2002 Winnebago Adventure and I have no water coming out of my hot water side of the faucet. I have flushed the tank and it will start to flow then a lot of air comes out and not water flow after that. Do have any recommendations as to what I need to do to fix this?