24RKS No Hot Water

[md2lgyk]

My 2010 24RKS has no hot water. I don't mean the water heater isn't working, but that whether using the onboard pump or external potable water connection, no water at all comes out when I open any of the hot valves on the faucets. This has been happening since I de-winterized the unit last Spring (didn't camp much this Summer due to building my house).

The unit has the traditional 3-valve setup for bypassing the water heater. I have read elsewhere that there is sometimes a check valve at the outlet of the heater that can fail shut, but I can't find anything like that. I did notice when de-winterizing that one of the valves (inlet or outlet, can't remember which) was much harder to turn that the other two, and the handle could actually be rotated more than 90 degrees in either direction. I'm suspecting that valve is defective and is shut. Is there anything else I could check before cutting into the plumbing?

[Crabman]

Welcome to the forum md2lgyk. It sure sounds like you have it nailed with a defective closed valve. Either water is not going into the water heater tank, which you can check by taking out the drain plug on the outside portion of the water heater and see if water comes out. Or water is going in the tank but cannot come out due to the other valve being defective and remaining closed. Either way there would probably be an airlock with only one valve open so the air in the tank could not expel out. I know I have to open up a hot water faucet and let the air out so the tank will completely fill up.I`m also not aware of a check valve on the heater tank, but perhaps another member with more knowledge on the water heater tank will chime in. Best of luck and let us know how it turns out.

[3'senough]

There should be a blow off valve on the top of the tank to release pressure should it need to instead of blowing up. Be careful when doing it as 120+ degree steam and or water could shoot out especially if you have an airlock situation. Before startup in the spring I always pop open this to confirm air is not in the tank and the elements are covered.

You open the valve by simply pulling up on the silver or brass lever slowly. There should be a red emblem on this valve with warnings and have female threads for adding extentsion pipes. Once you crack it you should hear air escaping and water filling the tank should it be airlocked. Once water comes out your full and all the air is purged.

If however the tank is not filling then it is in the feed from the waterpump and/or city water line. Check the valve on the bypass. This should be perpendicular to the line to be off. All valves going to the hot water tank should be parallel to their respective lines to be on. If still not filling then you have bad feed valve to replace. If it fills and the valve is open to feed the faucets then the outlet valve needs replacing.

[md2lgyk]

Thanks for the replies. I know of the "blowoff" valve you're talking about - same as those on residential water heaters. This is my third RV, but I have never before heard of the hot water tank being airlocked. I'll check that in any case.

[3'senough]

You're right in the airlock case. Most of the time if you open the hot line somewhere inside it will purge but since you may have a bad valve that air may not be able to get out.

I also pull that to drain the tank in the winter. Drains faster since the air gets right in. Less burping through the lines.