How to isolate WB Heatslave 26/32

[mitchino]

We have an oil fired Worcester Bosch Heatslave 26/32 combi boiler. It's always lost a bit of pressure i.e. topping up every week or so. However I came back from holiday and accidentally overfilled it, and something has obviously sprung a leak as now I have to re-pressurise it every few hours.

I spent yesterday lifting floorboards, inspecting valves and pipes etc and couldn't find an obvious leak. I now want to isolate the boiler so I can find out whether the leak is in the radiator circuit or the boiler.

How do I isolate the boiler? Which valves/taps do I close?

 

[oilhead]

Check for discharge from the pressure relief valve. If it is dripping, manually operate quickly for 5 or 6 times to see if it will reseat.

 

[mitchino]

Yesterday I put a freezer bag with rubber band over the end of the discharge pipe from the PRV to see if it was dripping, but all that happened was the bag filled with a bit of air. So I assumed the PRV was ok.

Following your advice today I located the PRV, and turned it anti-clockwise to operate it - is that right?

I then discovered that the compression fitting holding the discharge pipe to the PRV joint was loose and was dripping. So I've tightened that. But I would have thought that was just the water I vented when operating the PRV.

Will keep an eye on the pressure and see if there's any improvement.

Would like to know which valves to turn to isolate the boiler from the radiator circuit. To check if boiler is at fault before calling in engineer.

 

[mitchino]

Have inspected pipework using Installation and Servicing Instructions and the installer has not put any valves in for isolating the boiler from the heating circuit. Oh well.