water loss

[rm1]

got a job to go to where the client states that if he turns off the lockshield valves at the two radiators in the living room then the water pressure stays the same on the boiler but when the radiators are turned on there is a pressure drop in the system no leakage at radiators or valves any thoughts it is a vaillant combi boiler i firstly thought about a leak on the return from one of the livingroom radiators but if that was the case it would surely still effect the pressure irrespective whether the radiator was turned on or off maybe the client is getting confused

 

[Blake]

Yep, if the leak was on the return or flow to these two rads the pressure would still drop even if they were isolated.

How much pressure drop are we talking about? It does seem strange, have you tried isolating flow and return on boiler over night just to confirm the leak is on pipework and not at the boiler?

As you know custards often get confused

 

[efficient]

sounds stupid but have you bleed the rads, is there air in there? if so then its a matter of elimination like bronzino says shut off flow and return see if there is a pressure loss then try shutting down all rads see if there a pressure loss on the pipework then open one at a time

 

[rm1]

going to the job tomorrow will let you know the outcome

 

[stevetheplumber]

as the only thing thats change by shutting the lockshields is the valves themselves id open them and see if they leak through the spindles although i find they leak more closed usually

 

[rm1]

just to let you know the problem was that the expansion vessel needed repressurised due to the amount of radiators in the property it was blowing off via the prv