central heating

[MarcoB]

the pressure on my central heating system keeps dropping and the heating switches off. when i re pressure it it comes back on. any ideas why this is happening please?

[Willow Tree]

possibly a leak somewhere

[matt1e]

yes definitely losing pressure somewhere. if nothing obvious inside the PRV may be passing, have a look out side and see if there is any dripping coming out of the PRV discharge pipe

[musicman1956]

If it's a combi boiler. The expansion vessel will need recharging. As the water heats and expands, it can't go anywhere, so blows out of the PRS. as the water cools and contracts, the preasure drops. Check the expansion vessel pressure with a tyre gauge. It should be at about 2-3 bar.

[gucciman]

the pressure in an expansion vessel shold be 0.5 to 0.7 bar not 2 to 3 bar !!!!!!!!!!!