Carver Cascade GE~ No Hot Water

[StephenD]

Good Afternoonn All, hope you can help me.

I have a Swift Conqueror 640 1997 vintage and I cannot get ANY hor water.

In October last year I decomissioned the heater / caravan in readiness for the winter.

Now for the problem:

I have no hot water.

As normal I opened the hot kitchen tap and using the Whale external pump filled up the underslung water storage tank. Once full, I then switched the Internal pump on, which usually works the pressure switch, which then sends water to the open hot tap. But this is not happening?

The cold water in running fine in both the kitchen and bathroom taps, but I cannot get any hot water from either taps (Both are mixer taps). Please Help.

One thing I did notice this time was when I removed the external Whale pump (on the first attempt) to change the water barrel I heard a 'sucking' noise from the conection??. This as not happened since?

I have tried the following
(1) I have located, removed and cleaned the non return valve (although it was clean)
(2) I removed the hot water feed tube and blew through it, and heard a noise coming out of the 'opened' hot bathroom tap, which I then closed. I then commenced the same procedure with the kitchen tap but I could not heard anything from this tap? There does not seem to be any visible blockage.
(3) Micro switches on bathroom taps can be clearly heard working. But I cannot heard any micro switching on the kitchen taps? Not sure if they have them. I have checked under the sink area and there are just pipes leading to the mixer taps.
(4) I have emptied and re filled the system five times in order to try and purge the possible airlock if thats the problem!

I only use the heater on electric, I don't know if this makes any difference.

I have noticed that the pressure switch as started the pulse on and off. I had this problem last week when I located a small leak near to the pressure switch. There does not seems to be any leaks present.

SORRY for the length of my entry, but I would appreciate any assistance you could offer, before I have to call out a mobile engineer and take a secong morgage out.

Stephen

 

[Damian]

When you say you removed and checked the non return valve, which one did you check?
What location?

 

[StephenD]

The Non return valve of the heater.
As you look at the heater from the rear it is the right hand side bottom black connection

 

[Damian]

Thanks for that.
Are you sure the heater is filling with water?
The normal things which stop the hot water coming out are: the non return valve (but you say that is ok), something blocking the water channel between the inlet and the tank itself (the water has to travel through a small waterway from the inlet valve to the tank). and lastly, if the system is otherwise working, something blocking the tap (but you say that is not the case.)

 

[StephenD]

Thanks for getting back

I have checked the blue plastic waterway leading to the heater and there is water in that. I have actually emptied the heater twice yesterday so water must be getting in somewhere. The non return valve was clean and worked, I blew through it and could feel a very slight rush of air through the other side, should I replace it, the van is 14 years old? I checked both the taps and the cold water is running through them correctly.
I can not think of anything else.

 

[ProfJohnL]

Hello Stephen,
The lack of hot water at all of the taps points to some problem with the heater. Being a 1997 caravan it will have been fitted with a Carver Cascade 2 and as you point out in your post you have the mains electric GE version.

The Cascade 2 (all versions) are sensitive to any water left in the pipework when the water may freeze. This usually manifests its self as poor or zero water flow through the heater and thus also at the hot taps. If this is the fault, then the NRV on the inlet to the heater has been damaged. The action of any water left in the valve when it freezes is to push the small "O"ring valve seal off it's seating, and physically jam the valve. Often it allows a small weep of water through so the tank does fill but very slowly. This can account for your water pump pulsating with no apparent leak.

Bearing in mind that Air is much thinner than water, if you blew through the faulty NRV, then some air may get through, giving you your "slight rush of air" but with thicker water the flow would be much more restricted. Did you try blowing through it both ways round? If you got the same effect both ways then the valve is definitely faulty. In practice, there is a very light spring in the NRV and when you blow in the correct direction you should be able to produce quite a rush of air rather than just a little, and virtually none the other way round.

The valve may be repairable, Using the blunt end of a pencil or Biro, insert it into the pipe connection end of the valve. You should find you can push the internal shuttle against a weak spring enough to cause the nose of the shuttle to appear at the threaded end of the valve. Just under the shuttles nose is a grove designed to take the "O"ring. Sometimes simply refitting the O ring is enough to cure the problem, however sometimes the "O"ring and or the internal valve seat are damaged, which then needs the vale to be replaced.

Incidentally If you have a pressure switch system which you have, the micro-switches in the shower taps are not normally used.

 

[StephenD]

Prof John L

Thank you for the explanation.
I did in fact blow the non return valve at both ends and subsequently blew the inner parts out, I managed to re insert the parts, including the spring. I feel the purchase of a new NRV would be a good starting point.
I don't know what else it could be.

 

[StephenD]

Duplicate Post

 

[Guest]

There are three possibles, the least likely is something, such as a piece of a broken non-return valve, lodged against a 'tee' fitting in the pipe work.
Next is a faulty valve, I can say from bitter experience some will work perfectly while out, but will not when refitted, led me a merry dance did that?!
The other is as previously mentioned, a blockage in the passage between drain hole and tank, this will be loose lime scale flakes fluhed in during the last drain down
Simply test is to remove drain bung and then get someone to switch the pump on, if water spurts forcefully, perhaps a foot, out of the drain,then there is nothing wrong with the valve and the passage is blocked.
Solution to this is to open the hot taps and if you can, the quick drain valve above the drain bung, this is to let air out, now as best you can, but not to well, connect a hose pipe to the drain bung hole, with the non-return valve shut the force of water can only swirl around and work on the blockage so flushing the flakes out or back into the tank.

 

[StephenD]

Cheers Gary, I've just bought a new non return valve, and I will be fitting it on the weekend, I will try your reverse flushing though.

Many thanks for the help, and i'll keep you updated

 

[StephenD]

Replaced the Non return Valve. Hot water at last.

Thank you all for your assistance