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Discuss Shower runs cold when hot taps used in the DIY Plumbing Forum area at PlumbersForums.net

Bazza1687

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3
Hello,
I have just installed a new shower which works well, however if you open a hot tap anywhere else in the house the shower runs cold, however if I open a cold taps the temperature does not change. I believe my shower is only a mixer not thermostatic did not do my research when buying the whole bathroom from wickes. Water is coming from combi boiler thermostatic bar shower in other bathroom has no issues.

To resolve this do i need to fit a pressure equalisation valve.

Or do need to just reduce the cold pressure with a pressure reducing valve if this option any recommendations.

I did try reducing the flow of the cold with the isolation valve reducing the flow on the cold does stop the temp drop, would flow restriction isolation valve be an option? if so what flow rate should i install? No idea what the mains pressure is diyer no way of testing but flow rates are high.


Bristan Square Recessed Concealed Shower Valve with Diverter - Chrome 233690​


Thanks in advance
Baz
 

ShaunCorbs

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I’m guessing the new shower has a higher flow rate than the other hence why you haven’t had any problems before that’s normal and unfortunately it’s standard with combi boilers
 

Bazza1687

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3
I’m guessing the new shower has a higher flow rate than the other hence why you haven’t had any problems before that’s normal and unfortunately it’s standard with combi boilers
I’m guessing the new shower has a higher flow rate than the other hence why you haven’t had any problems before that’s normal and unfortunately it’s standard with combi boilers
Bummer is there a fix?
 

ShaunCorbs

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Flow limiter on the new shower or don’t use another hot while using the shower
 

Bazza1687

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3
Flow limiter on the new shower or don’t use another hot while using the shower
Would a flow limiter isolation valve do the job? if so how many litres an min? would it just be the cold that needs limiting or hot as well? Thanks for your help
 

ShaunCorbs

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Ideally you want to restrict it coming out the valve single outlet or dual eg hand held and rain head ?
 

John.g

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With hot tap open, if you turn the shower to fully hot does the temperature increase, if not, does it increase if you reduce its flowrate while still turned to fully hot?. You might also measure the flowrate and temperature from the hot tap. A 30kw combi should give a flowrate of 9LPM at 60C or 15.4LPM at 40C.
 

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