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Combi boilers and a new bathroom

Postby Julian » Fri Mar 21, 2008 6:17 am

I wonder if someone could answer me a basic question on plumbing.

I am changing a bath suite. The pipework doesnt have isolation valves. We have a combi boiler and I need to know what the procedure would be to stop the water and install my new bathrom suite. I have heard lots of horror stories on sealed systems and pressures etc.

Does someone have the proper procedure to ensure I do not ruin my boiler in the process???

many thanks
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Simply Build It

Postby Skids » Fri Mar 21, 2008 12:51 pm

Hi Julian,

As you have a combi I am taking it that the whole system is mains fed/pressure, hot and cold (no CWSC or HWC).

If so, turn the boiler off, turn the stopcock off, and turn the kitchen sink Hot & Cold taps on ~ no water (a little whilst it drains down), good so far.

Check the bathroom taps ~ no water.

Change the suite ~ fitting ‘full bore ball isolation valves’ to each pipe (x5)

Close the taps, open the stopcock & pressurise the system, check for leaks, if ok, run the boiler up, check the system heats and flows correctly.

“I have heard lots of horror stories on sealed systems and pressures etcâ€
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Postby htg engineer » Fri Mar 21, 2008 1:04 pm

For just installing a bathroom suite - turn off cold water stop tap. Now the cold and hot water will be isolated.

The problems you have heard of will be if you drain the heating system - older type systems - pressurised systems are no problem.
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