Advice on combi pressure loss please

[Madrab]

You can drop all the pressure out of a boiler by only losing a couple of Ltr's

 

[silver50]

You can drop all the pressure out of a boiler by only losing a couple of Ltr's

Thanks Rob

Any chance you could briefly explain the routine for isolating the heating side from the boiler itself? The pressure gauge still giving you your info on any loss? Not too sure how you can cut off flow/return and know what's going on.

 

[Madrab]

You need to ascertain if the pressure loss is from your boiler or from your heating system.
There are plenty of references in the archives and the 'net, but in short...

Turn boiler off; pressurise system; isolate boiler from system at flow and return connnections under boiler; wait 12 hours or so; check gauge on boiler if holding not boiler; open flow and return valves; if gauge drops then loss/leak is on CH system.

When you isolate the boiler at the flow and return valves, once the system is pressurised, then if the gauge drops it has to be the boiler as the gauge is showing the pressure within the boiler. If the pressure gauge stays the same and then pressure drops when you open the flow and return valves again, you know it's the CH circuit. As the pressure has already dropped in the CH circuit then pressure in the boiler drops into the CH system and the gauge drops with it.

 

[silver50]

When you isolate the boiler at the flow and return valves, once the system is pressurised, then if the gauge drops it has to be the boiler as the gauge is showing the pressure within the boiler. If the pressure gauge stays the same and the pressure drops when you open the flow and return valves again then you know is in the CH pipework, the pressure has dropped in the Ch system and the pressure in the boiler then drops into the CH system.

Cheers!