Only getting luke warm water from Carver Cascade 2

[Stevie P]

Hi all,
does anyone have any advice on where to start with a Cascade which has suddenly started only delivering warm water?

It's an old caravan but has been in constant use since March. Water was hot until just a few days ago. Should I bother looking at the non return valve for mixing issues or does that only happen directly after freezing issues over winter? Should I look directly at the element? I have a multimeter but have no idea what I'd be testing on an immersion element...

Any pointers much appreciated.

 

[ProfJohnL]

Bearing in mind the heater is now at least 22years old, age might have something to do with it now.

Q1. Can you tell us whether you were using gas or electric heating and whether you had the same problem with both fuel sources?

Q2.And how is your pump controlled is a pressure switch or by the micro switches in each tap.?

Q3. When you open the hot tap does the water come out instantly? Or does it take a few seconds starting with a lot of air? If the water is a solid flow the instant the tap is opened its unlikely to be a non return valve failure on the heater.

But there are a couple of things you can easily check with no special tools or skill needed.

The first thing is to check whether the heater is actually getting properly hot.:-
1. Make sure the heater is full of water by opening a hot tap and you are getting flow without interruptions and gurgles Turn the taps off.
2. Turn the heater on for at least 30 min. and don't use any water whilst it should be heating.
3. After 30min touch the top of the metal tank where it joins the casting, it should be hot like a domestic radiator, just about too hot to touch for long.

If it's warm to the touch and not hot then it suggests the heater is indeed faulty. But if its too hot to touch for long then it suggest the heater is probably ok, and we need to consider the pipes and taps.

Fairly soon after the Cascade 2 was introduced, there were a number of complaints about the water not being hot enough, and the fault was traced to the fat the caravan had a pair of taps for the shower (hot and cold) but the there was a third control that stopped the flow of water to the shower head.

If the hot and cold controls were left open, but the flow was stopped either by a third tap or a trigger controlled shower it was found the hot water for the rest of the caravan was being diluted by the shower mixer tap.

The solution was to make sure the mixing taps were turned off or to fit inline Non return valves into the inputs of both hot and cold shower feeds to prevent back flow between the hot and cold systems.

 

[Stevie P]

Excellent, thanks.

A1 only electric (all our vans have gas cut off to everything except hobs/ovens)

A2 Micro switches in the taps. (both have been replaced with cheap Comet London taps)

A3 Solid flow (unlikely to be NRV then)

I'll check the cylinder exterior temp tomorrow and report back - I was nearly ready to pop a connector and stick a push fit isolator on it so I could draw off direct hot water before the tap mixed it but you've saved me that hassle

The shower is a monoblock type controller with no other flow control so I assume it's not the final issue you described.

I'm so glad to find this forum. I maintain 20 caravans for a circus and usually just say hot water is uneconomical to repair but it's nice to know I may be able to delve a bit deeper here. Thanks!

 

[ProfJohnL]

First check the temperature of the actual heater as I suggested , as that will identify if the heater or the pipework in the caravan is suspect.

 

[Gralay]

Hi
Welcome to the forum
We had the same problem with a 1996 swift corniche, the carver cascade 2 has 2 thermostats 1 to turn off the element when the water reaches 70 degrees C, the other is an overheat stat in case the other one fails to operate, the temperature of the overheat stat is 85 degrees C and has a manual reset button. I think the first stat will be faulty and turning the element off before reaching 70. Both stats are still available Google carver cascade 2 thermostat
I personally would change both
Hope this helps

Gra

 

[Stevie P]

So, a bit of an update. Managed to get access to the heater both yesterday and today.

Yesterday, fter randomly pushing the reset button (not feeling like it actually did anything) and emptying and refilling the water system the hot water was working. After maybe an hour the tank near the casting was hot hot, so I ran the tap and the running water was hot hot. I thought MAGIC the reset button on the overheat maybe dodgy, just no real sense of whether it has activated or not.

This morning, luke warm water again. I jiggled the reset in and out again and run a little water through. Again, an hour later it's working better - hot this time though, not hot hot like yesterday. (could it be on a cool down curve after the overheat cut out again?)

I'm leaving it again another 20 minutes after another jiggle of the reset button to see if the temperature is on the way up or down, or static.

It certainly seems like the temperature of the tap water corresponds to the temperature of the exterior of the tank, I assume removing the suspicion of hot/cold mixing issues?

 

[ProfJohnL]

...., I assume removing the suspicion of hot/cold mixing issues?

Thank you for the update. From your results it does look like it could be a failure of the heaters electrical thermostatic switch, causing it to exceed its normal switch off temperature, and the exceeding the over temperature reset switch.

I think Graylay's suggestion of changing both stats would be a sensible start, and provided you can access the rear of the heater, it is possible to swap them without removing the heater from the caravan.

I would also recommend checking the heater's electrical safety (Portable Appliance Test) as older elements can start to fail.

 

[Stevie P]

Thanks for the advice.

I take it there will be no difference in this part between the Cascade 2 and the GE since the function is irrelevant to volume or wattage? (just looking at how spare parts are labelled)

I also see some parts labelled pre-1991. Should I be looking to identify the age of the unit in question?

Thanks, invaluable info here

 

[ProfJohnL]

Thanks for the advice.

I take it there will be no difference in this part between the Cascade 2 and the GE since the function is irrelevant to volume or wattage? (just looking at how spare parts are labelled)

I also see some parts labelled pre-1991. Should I be looking to identify the age of the unit in question?

Thanks, invaluable info here

The Original Cascade 2 (circa 1984) was gas only, it was modified to accept a mains 230V element and the model was renamed Cascade 2GE (GE denoting Gas & Electric) a further development in the early 1990's increased the mains element wattage and the unit was called the Casacde 2 Rapide.

In 1999, Carver sold its Caravan products division to Truma and in 2000 they ceased production of most Carver products including the C2 range. Truma continued to supply some spare parts for Carver Products but now you have to go to other sources for items like the thermostats.

 

[Stevie P]

Thanks so much for this info.

Since it's labeled as 830w I'm assuming it's the Rapide , thus no need for the pre-1991 parts. So, I've ordered both thermostats - there are a fair few people offering them - I'll report back once fitted and tested.