Shower with hot and cold water differential pressure problem

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Simple Simon
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Fri Aug 16, 2019 9:42 am

Picture a ground floor (non-combi) boiler heating a hot water tank situated in the airing cupboard on the first floor (top floor). In the first floor bathroom is a stand-up shower in the bath. It has basic shower mixer taps, where you have to play with the hot and cold taps to get the right temperature on the shower. We've all experienced these. Problem is that the cold is coming in at mains pressure and the hot is coming from the tank which is on the same floor and therefore under much less pressure. It takes excessive fiddling and time to overcome this issue to stop the water always going cold. The solutions that came to mind were: (a) move the hotwater tank out of the airing cupboard and into the loft just above (not ideal!) (b) add a pump, (c) simply install a termostatic mixer tap in the bathroom, which would in theory automatically regulate the temperature coming out of the shower head. Before I start spending time and limited resources on either option, I would be grateful for some advice on which would be the cheapest and/or most effective solution. Would my termostatic mixer idea work, as that's probably the easiest? Thanks in advance for any advice received. Simon
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Shower with hot and cold water differential pressure problem

Post by Bob225 » Fri Aug 16, 2019 10:35 am

All it is, is the lack of head pressure, as you rightly assumed, a pump should sort the issue, a thermostatic mixer will still need the head pressure to work correctly

The other alternative is to fit a electic shower
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Sat Aug 17, 2019 9:22 am

Hi Bob, Yes, someone told me a thermostatic mixer would be enough, but I thought that even that would not cope with such a massive pressure differnce. In the light of your advice I am thinking of a getting an electric shower. I have to weigh the costs with adding a pump to the existing system. I guess if I got a pump, I'd really want a thermostatic mixer too? Is there any plumbers trick to add pressure to a hot water tank, without actually having to move the tank? E.g. having some kind of header tank in the loft which feeds the hot water tank? Would that also work? Thanks for your help! Simon
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Shower with hot and cold water differential pressure problem

Post by Bob225 » Sat Aug 17, 2019 10:39 am

There is a bonus of a electric shower if the rest of the house uses all the hot water up, you still get a hot shower without having to wait
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Shower with hot and cold water differential pressure problem

Post by wine~o » Sat Aug 17, 2019 5:36 pm

How big is the header tank ? if it's one of those tiny ones that sits on top of the HW cylinder then the pump is a no go. More info please and pics are always a bonus.
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Wed Aug 28, 2019 1:13 pm

Dear wine-o,
Thanks for your reply! I will attach a photo below of the airing cupboard. Please note there is currently NO header tank in the loft. The boiler is on the ground floor and heats the water which is in the storage tank, which in turn feeds the hot water tap on the shower mixer. Does that make it clearer?
Thanks.
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Shower with hot and cold water differential pressure problem

Post by wine~o » Fri Aug 30, 2019 12:46 pm

Never seen a set up like it, I can see the flow in from the boiler but there doesn't seem to be a return ?
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Tue Sep 03, 2019 5:34 pm

Hi there,
Thanks for the reply. I'm not a plumber, so I don't know. I assumed it was something very standard, as it's a modern house and this system been in use for ca. 20 years, so it must work. I just wanted advice about the pressue issue.
Thanks, Simon
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Shower with hot and cold water differential pressure problem

Post by wine~o » Wed Sep 04, 2019 2:57 pm

All I can really say is that I wouldn't want to be installing a pump to the hot water without knowing how the HW tank is fed.
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Wed Sep 11, 2019 10:06 am

Dear Wino,
Thanks for replying again. Thanks for your reply. I will not fit a pump. I hear what you say, but can I add a header tank in the loft, as an alternative way to get more pressure, or can't you answer that either without knowing how the system works?
Sorry to ask again, but I am not a plumber, hence the need for advice on this site. I am happy to take further photos if that make it easier to see how the set up works?
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Shower with hot and cold water differential pressure problem

Post by wine~o » Wed Sep 11, 2019 12:57 pm

Putting a tank in the loft will be very disruptive unless you have a huge loft hatch, even if that is an option. Probably best to get a man in to have a look and see what options you have. shouldn't charge for coming out to look advise.
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Shower with hot and cold water differential pressure problem

Post by Simple Simon » Wed Sep 18, 2019 10:56 am

Thanks for those who replied, especially wino. I am not going to post again, as it is clear from wino that the problem will require a call out as it is clearly not something that can be answered without attending the property. I may choose the electric shower option, as this is the only one that will not involve making expensive alterations to the plumbing. But thanks again for all the advice.
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