Brist

[Dean3k]

I just moved into a property and the Bristan 1901 thermostatic shower runs luke warm/cold, I believe the unit has been in for a couple of years. It runs from a combi bolier and the cold water pressure is very high in the house. The pipe going into the shower is very hot. Is it likely that there is just to much cold water and I need a pressure reducing valve for the cold or is it likely the thermostat in the unit has gone faulty?

 

[dontknowitall]

No easy black and white answer here (to my mind at least).

My guess is a pressure reducing valve will be the best bet.

But this will be a waste of money if you don't know how high the pressure is at the moment. If it's about 3 bar, then a pressure reducing valve will make little difference and it's likely to be the shower unit.

Alternatively it could be the pipework, or possibly how the combi interacts with the system.

Hopefully others will have alternative suggestions.

 

[willplumber]

when you say the pressure on the house is high, is it high in the bathroom too? or just kitchen, is the cold all mains or do you have gravity fed cold in the bathroom (i know sounds stupid with combi boiler but i have seen it, the property had back siphon and the upstairs flat and there flat was flushign with HOT water)

Will

brighton-plumber

 

[Dean3k]

when you say the pressure on the house is high, is it high in the bathroom too? or just kitchen, is the cold all mains or do you have gravity fed cold in the bathroom (i know sounds stupid with combi boiler but i have seen it, the property had back siphon and the upstairs flat and there flat was flushign with HOT water)

Will
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The cold water is mains fed, the pressure is high both upstairs and down stairs. example: If I have the hot tap fully turned on in the bath I only have to turn the cold tap a qtr turn and the tap runs cool.

 

[willplumber]

well does sound like as before a pressure reducing valve will be the first port of call. at the end of the day thats cheaper to put in then a new shower mixer, give that a go first then move on if it dosnt work.

does sound like the hot has much lower pressure than the cold. the problem is that if you reduce the cold down and the hot is low already, your shower may be a rubbish trickle rather than a steaming high pressure pleasure.

whats the pressure read on your boiler?

Will

Brighton Plumber - your local brighton plumbing expert

 

[Dean3k]

well does sound like as before a pressure reducing valve will be the first port of call. at the end of the day thats cheaper to put in then a new shower mixer, give that a go first then move on if it dosnt work.

does sound like the hot has much lower pressure than the cold. the problem is that if you reduce the cold down and the hot is low already, your shower may be a rubbish trickle rather than a steaming high pressure pleasure.

whats the pressure read on your boiler?

Will

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I think our combi bolier only shows the pressure for the central heating, which is around 1.5 bar.

 

[leakylea]

your pipes may be reversed

 

[migoplumber]

the combi will only heat a certain amount of litres per minute of water, the faster you pull it through the less it will heat it. if you have good pressure on the cold you should have good pressure on the hot minus a bit for losses, and clearly it wont be as hot.

have you checked you actually have mains pressure at entrance to boiler?

could there possibly be a tank in loft?

if you have mains pressure and flow at input to boiler, you should have virtually the same at exit (dont quibble on pressure losses)
if you dont a possible cause is blockage or cal up.


good luck
shaun

 

[Dean3k]

the combi will only heat a certain amount of litres per minute of water, the faster you pull it through the less it will heat it. if you have good pressure on the cold you should have good pressure on the hot minus a bit for losses, and clearly it wont be as hot.

have you checked you actually have mains pressure at entrance to boiler?

could there possibly be a tank in loft?

if you have mains pressure and flow at input to boiler, you should have virtually the same at exit (dont quibble on pressure losses)
if you dont a possible cause is blockage or cal up.


good luck
shaun

Definitely no tank in loft, spent most of the weekend boarding out the loft.

I'll try the PRV and see if that works, if not, I'll call a professional.

Thanks.