Carver cascade. Hot water issues

[adyt61]

Hi

I have a Lunar Ariva 1999 fitted with Carver Cascade.

The flow from the cold water is superb on all taps.

The hot water starts superb, then slows within about 15 - 30 seconds to a trickle. Turning the tap off for about 30 seconds, then turning back on simply repeats the problem. It is the same on all taps.

Also, as the flow reduces, the pump starts to chatter.

I have used a strong solution of tank cleaner twice but it hasn't really helped.

Cheers

Phil

 

[Damian]

From your description it sounds like the cold water inlet fitting has failed. or the non return valve located within the fitting, has to be precise.

 

[ProfJohnL]

From your description it sounds like the cold water inlet fitting has failed. or the non return valve located within the fitting, has to be precise.

Totally Agree

 

[adyt61]

Hi Guys. Many thanks for the quick response. The inlet valve failing is the most logical answer so I'm going with that. I've sourced a replacement, but as for fitting would appreciate any comments on;

1. Is it worth fully heating the tank before draining. My theory being warmer, softer plastic is less likely to break than colder plastic?

2. Given the old inlet breaks, any advice on removing the unit, or a website I could go to for instructions/diagrams?

Cheers

Phil

 

[ProfJohnL]

Hi Guys. Many thanks for the quick response. The inlet valve failing is the most logical answer so I'm going with that. I've sourced a replacement, but as for fitting would appreciate any comments on;

1. Is it worth fully heating the tank before draining. My theory being warmer, softer plastic is less likely to break than colder plastic?

2. Given the old inlet breaks, any advice on removing the unit, or a website I could go to for instructions/diagrams?

Hello Phil,

The original fittings were made of a fairly hard plastic, and over time they do become more brittle. Consequently I seriously doubt warming the tank will make removal any easier. What I will say is use a little vegetable oil as a lubricant when you fit the new components.

The cold water inlet sits directly in line with the external drain plug. This means if the fitting does break off when you try to remove it, sometimes but not always the remainder can be driven out with a large screwdriver through the 'Drain hole' plug from the outside.

If that isnt enough then more serious work is involved, which may need the heater to be removed, You should only disconnect a gas appliance if you are fully gas competent, and know how to seal and test etc. If in any doubt refer the removal and refitting to a qualified LPG fitter

Once on the bench, the residue of the fitting should be carefully chiseled out taking care not to damage the metal thread and then run tap down the thread to clean it out properly. Blow or wash out then fit the new part taking care not to over tighten it.

 

[Damian]

Much depends on how much room you have to get to the cold water inlet as it is near the floor and often in a very awkward place , if that is he case the heater needs to be removed.

The old inlet will almost certainly break as soon as you touch it.

To get the remaining part out, DO NOT use a chisel !!!!!!!!!!!!!

Use a junior hacksaw blade and gently cut four or five equidistant slots in the plastic , the blade will just fit down the centre, and you will know when you have reached the metal of the heater as it will sound different and will catch rather than a smooth cut,,,,,STOP!
Then use a smallish flat bladed screwdriver to ease each segment out of the heater, you only need to remove one or two segments before the rest will become easy to unscrew as it collapses on itself.

If you have a suitably sized tap it is worth running it down the thread to remove any scale etc but if you don't have a tap (and most people don't) you can use a towball bolt to do the same job, just be very careful.

You can use either a smear of olive oil or a squirt of silicone lubricant on the new fitting to ease refitting and only tighten enough to ensure a water seal, the new fitting will have a new O ring so hand tight plus a little bit is enough.

If you are not competent to deal with the gas side, you should get a mobile engineer to do it for you.

 

[swpostie]

What sort of tank cleaner have you used?

I use a few sachets of ordinary kettle dealer, in my tank, from time to time, having suffered problems similar to yours in the past.

I've also replaced the non-return valve on the water inlet, a number of times, without breaking anything!

 

[adyt61]

Hi Guys

Thank you everybody for very informative and clear replies.

Currently using the caravan so won't risk leaving myself water-less now, but it will get done.

I'll try and remember to post the result, or ask for more help!

Thanks again all.

Cheers

Phil

 

[paws]

Just a thought Phil, but if you are going to replace the bottom (inlet/non return valve) on your Carver water heater then it may be worthwhile renewing the top (hot water outlet) plastic fitting at the same time.

They cost around £7 each and as the plastic gets brittle over the years they tend to break off at the slightest touch.

The top fitting is often the easier one to "get at" and if you are lucky will come out (unscrew) in one piece

I have just replaced both fittings on my caravans Carver (20 years old) when the bottom one failed causing the same sort of symptoms that you experienced.

As a final check, just in case you are still not getting piping hot water on electric and after replacing the inlet/non return valve, and to make sure that the element in the water heater is working OK it should be drawing something in the region of 3.25amps, if its not then it could well be a wiring fault or a dud element.
Happy Caravanning
paws

 

[dee_gee]

I'm having bother with my carver cascade hot water too (it's 16 years old). Used the van for first time this year yesterday and got the water system primed up. End result is that cold water is perfect in kitchen sink, washroom and shower. Hot water is perfect in washroom and shower, both furthest away from the Carver, but the hot water tap in the kitchen sink just dribbles with cold water. I wondered initially if there was an air lock, but given the hot water further down the pipe makes me think not. I then wondered if the microswitch in the kitchen tap might be faulty, but I hear it click for both cold and hot, plus, when trying to get it to run hot water, the pump is running at the aquaroll.

I'm stumped.

 

[ProfJohnL]

Hello Dee Gee and welcome to forum.

The Cascade is the model of the water heater, and it was supplied separately to any other pipework or fittings.

As you have a good flow of hot water to the washroom then that shows the heater is working normally, and the problem you have is with either the pipework or the fittings in the kitchen.

,To establish if its a problem with a microswitch in the kitchen hot tap try this:

Open the kitchen hot tap. Then whilst its open just turn on the cold tap If the hot water starts to flow then it means the pipes are clear and you must have a problem with microswitch in the kitten hot tap.

If the hot doesn't flow then it means you do have a problem with either hot pipe work or the hot tap.

Hope this helps

 

[dee_gee]

Hi. Thanks for your reply. The tap in the kitchen is a mixer, which I guess makes your test impossible. I'm wondering if there's a blockage to the hot tap. Main reasons being that I hear a click when I turn the hot tap, plus the pump starts to run, which I think suggests the microswitch is working? The dribble that comes out of the hot tap isn't hot, by the way, which is probably significant.

 

[Damian]

If the pump runs as it should when you open the tap to hot but nothing comes out, or as you say a dribble, then you have a blockage in the hot water pipe.

When opening the hot tap it will not be instant hot water as it has to travel the length of the pipe first.

The only way of seeing what is happening is to remove the tap and pipes to it and run the pump on hot.
Obviously you will need to make arrangements to catch any water that comes out !!!!

 

[dee_gee]

Hi. Thanks. As I suspected. The caravan is getting a service in a couple of weeks, so I'll let them do the fiddly stuff under the sink!