Mixer Shower - No hot water

mattaius25 · 16 Dec 2009

I have recently updated my mixer shower. It ran off 2 x 22mm pipes with a conventional shower hose and head. The 22mm pipes now run into a 15mm mixer tap, with piping fed behind the shower wall up to a monsoon style shower head but for some reason I have no hot water pressure. It's gravity fed. It worked the first few times and the cold water pressure is fine. I even had a pump installed which worked the first few times, but again, now all I get is cold water and when I switch to warm/hot the pump shuts down and I get no hot water at all.

My handyman bloke came and dismantled the mixer tap and the hot water flowed fine. He put the tap back on and the shower ran fine for 20 minutes. The second time I used it after he left, I had no hot water again. This has happened twice and no-one I know seems to understand what's going on.

Any ideas??

advancemaintenance1 · 17 Dec 2009

ask your handyman mate to see if there is a gauze anywhere on the hot side of the tap/shower. sometimes bits of solder and crap can get caught behind it and the flow can be reduced or stopped, especially on a gravity fed system. if there is, remove it and run hot for a good ten mins and clean gauze. hope this helps.

tdesnos · 17 Dec 2009

What height is the hot water cylinder in relation to the shower head? Try holding the shower head as low as possible and then turning on the shower - sometimes it can be too high for the pump and thus the flow to small for the pump to detect a demand

dextrous · 17 Dec 2009

Is the cold water to the bathroom supplied from the mains or the tank?

mattaius25 · 18 Dec 2009

Thanks for all the replies.

I'm not sure if the cold water is mains or tank, I will try and find out. The shower head is fixed to the wall so I am unable to adjust the height. The head is above the level of the tank though.

We thought it was simply crap stuck in the pipes, but even after dismantling the tap (everything looked okay, water ran well and no crap came out of the pipes) I encountered the same problem.

I thought the pump would help but it simply shuts down when I try to get hot water out of the shower.

TicklyT · 18 Dec 2009

tdesnos said:
What height is the hot water cylinder in relation to the shower head?

The position of the hot cylinder has no effect on the flow to the shower. That is determined by the position of the cold water storage cistern

Are there any potential air traps in the pipework from the hot cylinder, say, from mounting the pump above the hot cylinder, or teeing the pump supply from the top outlet of the cylinder instead of using a surrey or essex flange?

mattaius25 · 18 Dec 2009

Air trap seems the most likely I think.

Excuse my ignorance but what's the best way to get rid of the air?

tdesnos · 19 Dec 2009

TicklyT said:
tdesnos said:

What height is the hot water cylinder in relation to the shower head?

Click to expand...

The position of the hot cylinder has no effect on the flow to the shower. That is determined by the position of the cold water storage cistern

Are there any potential air traps in the pipework from the hot cylinder, say, from mounting the pump above the hot cylinder, or teeing the pump supply from the top outlet of the cylinder instead of using a surrey or essex flange?

My bad, i meant 'storage cistern' not hot water cylinder.

To remove an air lock connect open up the hot and you need to force main cold up the pipe somehow and for a while and then remove the pipe and allow the water to run out. This i have never done in practice by the way!

glasgowgas · 19 Dec 2009

mattaius25 said:
Air trap seems the most likely I think.

Excuse my ignorance but what's the best way to get rid of the air?

have a look in the FAQS and plumbing fixes and tips, a good detailed description of how to do it is in there

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Mixer Shower - No hot water

mattaius25

advancemaintenance1

tdesnos

dextrous

mattaius25

TicklyT

mattaius25

tdesnos

glasgowgas

DIYnot Local

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