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Water heating up but needs 2 taps on to come out

Posted: Thu Jun 01, 2023 3:19 pm
by chh
Hello, I'd love some advice on my system, I've had a couple of plumbers come in that seemed to specialise in gas systems and seemed perplexed by my all-electric systems and the issues I'm having. My system is all electric heating and hot water system, in a flat on the 4th floor. The mains pressure has already been verified by the building plumber to be good (not sure the value, but pressure out of kitchen tap is strong, and overall pressure seems good).

The problem is that, although the water is heating up fine and the hot water cylinder gets filled, I can often only get hot water at the tap if I run another tap at the same time. I need hot water at the shower I need to keep the sink running as well. If I run the shower and the tap (set to hot) then the shower will get hot but the tap will be stone cold, and the shower will keep working hot even if I turn the tap down to a trickle. It seems like the hot and cold water pressures are not balanced, and perhaps need recalibration, but I'm not sure where. The tun dish seems to be activating occasionally – I've never managed to catch it to figure out when, but I need to keep a container under it because there is enough splashing that a small container fills up over the course of a week (e.g. around 300ml over a week).

The heating seems to work fine when it's needed, but even when it's in action the hot water functions as above.

The systems consists of an electric boiler (Heatrae Sadia), a 300L accumulator (GWS), a pump to fill the accumulator (GWS) and a large hot water cylinder (there's also a Harvey MiniMax water softener).

The problem is there about 70% of the time, but sometimes it works exactly as it should, so it feels like the hot water pressure is just not quite enough at some points and the cold water pressure therefore prevents it coming out at all.

Does anyone have any suggestions about how I could resolve this?

Re: Water heating up but needs 2 taps on to come out

Posted: Sun Jun 04, 2023 10:43 pm
by stoneyboy
Hi chh,
Have a look at the tank and local pipe work and see if the hot and cold have been joined and a valve (which should be closed) is open.
Regards S

Re: Water heating up but needs 2 taps on to come out

Posted: Mon Jun 05, 2023 4:50 pm
by chh
Thanks for the suggestion, that sounds like it could be the problem – what does that valve look like, or what could I google for to find an image of it? I assume it doesn't look like a tap – does it have a means for switching externally from open to closed?

Re: Water heating up but needs 2 taps on to come out

Posted: Mon Jun 05, 2023 10:11 pm
by stoneyboy
Hi chh,
I only mention it as a possibility because I have found this link pipe in some installations. You will have to follow the hot feed out of the hot water cylinder and see what connection are made into it.
Regards S