re carver cascade 2. nothing from hot taps

Aug 14, 2020
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Hi, Had a good look at forum but I don't see exact problem. We have no water from hot taps. Pump seems OK but will stay on indefinitely unless pressure switch tweaked. Cold taps OK. Tank seems to heat up OK. Pump make different pitch noise when hot taps opened. I can hear microswitch on sink tap but bathroom tap a bit too squeaky to be sure. Any ideas please ? Thanks, Dominic
 
Nov 6, 2005
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It shouldn't have both a pressure switch and active micro-switches in the taps - the pump should be switched by one or the other - although some taps have micro-switches left unconnected
 

JTQ

May 7, 2005
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Don't put on the heating be that by gas or if the dual model electricity untill you know for sure it is filled with water, otherwise real damage could result.

Normal water circuits place a non return valve either in the inlet to the boiler or the outlet so reversed flow can't occur. These can stick closed giving what you are seeing.
These valves frequently appear as a coupler, a short plastic tube inserted in the piping of the hot water system. Check it functions freely.
 

Damian

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Mar 14, 2005
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There are a couple of reasons why you have the problem.

First of all, before you put any form of heating on you must ensure the tank is full.

To check if water is actually going into the heater, having said none comes out of the tap, remove the drain bung behind the external cowl and operate the pump, water should come out quite quickly.

If it does not, then the non return valve which is situated in the cold water inlet fitting on the heater has stuck and will need replacing, or the inlet waterway is blocked with limescale.

In either case it is advisable to get a mobile engineer to sort it out as the Cascade is an old heater and needs very careful handling to avoid damaging it beyond repair.

The various fittings are very brittle and will almost certainly snap when being removed and it is a delicate job to remove the broken bits that stay in the heater, also if the tank has to be separated to clear limescale then in all likelihood the tie bar will snap and need replacing , and getting the broken bit of tie bar out is very very delicate and needs special attention to avoid damage that will render the whole unit scrap.
 
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Aug 14, 2020
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Thanks everyone for your thoughts. Am right in thinking that the tank is not full unless the open (hot) taps yield water? The aquaroll is definitely emptying and there's no leak now I've changed the O ring at the drain plug. I'd love to know where the water is going!
Also although I'll take your advice and get someone in if it's the NRV that needs changing, is there a way to definitely diagnose that as the issue? If there is anything that can be undertaken by careful DIY then I would love to have a go.
 

JTQ

May 7, 2005
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Hot will only come out the hot taps after the Carver has fully filled and the water continues to enter it, thus deplacing the water in it.

Re DIY:
The screwed in connections are a plastic which tends to become very brittle with age etc, the more so the "nylon" coloured earlier ones, less so the later black version. The broken off piece left in the unit can be challenging to remove. Plus the units aluminium body is prone to corrosion, making retapping to tidy up its threads prior to fitting replacement "desirable". I made my own improvised tap tool from a 16 mm bolt [ as best I remember], to do this cleaning up task. The reminans of the old fitting I removed by first making a screw driver "slot", with a heated up piece of correctly sized steel plate. I am sure other techniques have been used, this seemed the "kindest" I could think of at the time, these are delicate units and probably even more so with increasing age.
 
Mar 14, 2005
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sorry just re-read Prof John L 2nd para. Will try that first.
I'm sorry but I haven't commented before on this thread!. So what are you referring to please?

I suspect you have posted in another thread, and I responded to that.

Its much more coherent if you you keep a problem to just one thread, so all questions and answers are together.

If you ask one of the Moderators they may combine the threads to avoid further confusion.
 

Damian

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I have a feeling that the OP actually meant he had re- read my post and ref the 2nd paragraph as he has only this topic running.
 
Aug 14, 2020
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Almost certainly, in fact. Anyway I'm very grateful for all your interest and advice, in light of which I have engaged a mobile service engineer for next weekend.
Thanks again D
 

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