Leaky central heating

[dwalsh1]

Hi everyone. First post so here goes. I have a Bosch Worcester 35CDI II combi boiler. It keeps losing pressure, not by much but gradually goes down slowly from say 1 bar which is what I have it set at to around .7 bar at the moment. I keep topping it up to 1 bar but it loses pressure after a week or so. Now that tells me there is a leak in the system. I have had the gas board look at it because it is under contract and my wife said the fitter poured some liquid into the system to stop the leak but it don't look like it worked. Now my problem. There is no water marks on the downstairs ceiling so that tells me the leak isn't upstairs so I'm assuming it has to be under the front room floor which is hardwood (apart from under the stairs where the electrical consumer unit is). There is no way I'm gonna pull the floor up (assuming the leak is there) so this is what I'm going to do and that's where you lot can help. Coming from upstairs down the wall (hidden under the stairs) and disappearing under the front room floor are the flow and return pipes 1/2 inch copper. If I drain the system and cut the flow and return pipes that feed downstairs rads and then cap both pipes off would I need to join them making the circuit so to speak or just leave them separate. Once I have done that I then fill the system and then monitor the pressure gauge on the boiler to see if it loses pressure and then know for sure if it losses pressure the leak is under the front room floor. I have had dealings with British gas before and don't have a lot of confidence in their fitters. COULD it be that the boiler is losing pressure and causing the pressure drop. Your thoughts please.
dennis

 

[JAP&H]

Hi dwalsh1, welcome.

You could isolate your boiler from the system for a period of time.

If the pressure drops during this time, leak on boiler.

 

[mountainman]

If it's under contract with the Gas Bored then ask them to deal with it, that's what you have a contract for.

 

[dwalsh1]

Hi dwalsh1, welcome.

You could isolate your boiler from the system for a period of time.

If the pressure drops during this time, leak on boiler.

How do I isolate the boiler?
mountainman
I'm not sure the contract allows for the floor to come up and be put down professionally.

 

[mountainman]

Isolating the boiler properly would involve capping off the heating circuit.
As for your floors you need to consult your contract.
I doubt that a BG contract is that generous.

 

[PlumbBobBob]

what about your household insurance? would it be covered under that

 

[jtsplumbing]

All you have to do is close off the 2 valves under boiler , 2 x 22mm flow/return pipes.

 

[glenno1]

Is there any signs of water outside underneath the blow off pipe/pressure relief pipe when heating is on

 

[JAP&H]

How do I isolate the boiler?

Beneath your boiler there are isolating valves for the flow and return pipe work.

If you are unsure of this procedure then it may be time look for assistance other than BG.

 

[dwalsh1]

OK thanks for your replies everyone. If by isolating the boiler it needs capping off then I would rather do it at the point of where I think the leak lies and the best place for me to do that would still be under the stairs which brings me back to my original question, do I need to join the flow and return pipes together or leave them both capped? When the leak is narrowed down to up or downstairs then I will ring my insurance company and find out if I'm covered.