Hi all, just prepping the caravan for the first trip out this year and have an issue with the hot water system.
I have cold water to all taps but when they are closed and I call for hot water, none flows to any tap. I have drained the system a few times to remedy the fault and their is hot water in the heater when I drain it, so that's getting hot, but its not getting to the taps and the pump doesn't fire up either on the hot taps.
The van is a 96 Abbey County Oxford and has a Carver Cascade system.
A bit of research points to either a microswitch but the only microswitches I can locate are on the shower taps,we never use it, and none on the kitchen sink or toilet basin.
The other area possibly is the heater non return valve, any ideas which valve that is on the heater?
Any ideas on which to try first
Or if you have any other ideas, please let me know, I'll give anything a try.
If you've got microswitches on the shower tap, then you'll have them on the others too as it's beyond convention to have a mix of switched and pressured system in a van, plus I'd expect you'rs to be switched with it being a '96 van too.
Despite not using it, have you tried calling for hot water from the shower tap? It's not unusual for multiple switches to fail and the hot tap switches seem more prone to failure too.
Try switching on the cold to a slow run to switch the pump in, then turn on the hot tap to see if you get a warm mix. If you do, it will be a switch issue on the hot tap(s). If not, explore the non-return valve that's sometimes positioned after the water heater (you can temporarily by-pass), but my guess is switches from your information.
Thanks Paul for the prompt reply. In my haste I for got to mention that I tried all the other hot taps calling for water and still nothing. Really odd bur I've looked under the kitchen sink and bathroom basin and there are definately no wires to switches, just the shower, unless they are sited elsewhere for these two tap sets...possibly honing more towards the problem being the non return valve?
It sounds odd to me Rich, given you have switched taps on the shower. The switches are usually on the taps themselves as they operate (usually) by a cam on the tap actuating the switch, which in turn calls for the pump to run. Because they rely on the mechanical operation of the tap, they don't get positioned remotely.
On a non-switched system, you have a pressure switch that senses a tap being opened by reduction in system pressure, which then switches the supply to the pump on. It's not likely you'd have a mix of the two systems, unless some odd retro-fit work has been carried out.
Quote: Originally posted by Bloody Wind on 31/3/2012
... I for got to mention that I tried all the other hot taps calling for water and still nothing.
Have you tried calling for hot while a cold tap is already running though to see if you get a warm mix i.e., indication the hot water is being drawn from heater?
Not all systems have the non-return after the water heater, but given the other investigation you've already done, it does suggest this valve could be culprit in your case.
Let us know what you find.
The non-return valve is part of the cold water inlet fitting on the bottom right corner of the Cascade.
A quick check if it's working or not is to remove drain bung and switch the pump on, water should spurt out about a foot, if the flow is poor the non-return valve is the most likely problem
Unless already replaced with the later black plastic fitting, it should then be a white plastic fitting, if so you can slacken the jubilee clip and unscrew the outer nut nearest the hose, don't try removing the whole thing from the heater or it will most likely snap off.
Once the nuts undone, you will find a nylon 'shuttle' with a tiny white 'o' ring on one end, make sure it's perfectly round and in place. If all looks good you can put it all back together.
If it still does not work it will need replacing.
If it's already black plastic, then while testing with the pump on, try wiggling the tip of a slim screwdriver at the back of the drain bung hole, this will 'tickle' the tip of this style valve and combined with the pump pressure often frees it.
Superb advice as usual gents, many thanks. Going with a replacement of the non return valve, tried all the suggestions, no spurt of water from the drain plug, the valve is the white version, I take it this would have been the original, is there a difference in white and black versions or is the black the newer replacement?
Thanks again everyone, I'll let you know how I get on, may be of use to others in the long run.
Any ideas on the colour of the valve, do I need white or black?
The black one is later replacement but they are not easy to change, not only because access is difficult without removing the heater, but generally the old one snaps off and leaves the threads in the casting.
So I would go for trying to fix the old one first, not just because of what I just said, but because it's a better design and less prone to cause problems!
Thanks Paul and Gary, just an update. Heater out and one way valve changed, yes it did snap off but the remaining bit was easily removed with a bit of time and patience.
All connected back up and sealed, water now runs to hot and cold BUT now no heating of water on electric just the gas system?
Any ideas, could the element also have been damaged over winter as the valve was, although the system was drained down. Bit wary of electrics in terms of testing, but any ideas where or how I could rule out various areas to identify the problem.
The water heater switch is illuminated and the trip has not tripped, and I've double checked the wiring I had removed.
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Topic: No hot water to any tap - Cold ok
