Boiler / Central heating problem

[diycooper]

I have a Vailliant eco tec pro 28 boiler and the pressure is dropping overnight whether the boiler is on or off from 1.5 bar to 0.9 bar and turning off the heating. I cannot find a leak anywhere in the house unless I have missed it. I do not think it is the expansion vessel as the bar is not rising to 3bar. I have read it could be the PRV valve so tonight I have put a bag over it to see if water goes in it. I have also filled the boiler up to 1.5 bar and shut off the flow and return valves to see if it is on the system side. What my question is if the flow and return valves are shut and it is not on the system side will the prv still give out if it is that or will I have to try again tomorrow when the flow and returns are open ?

 

[swbjackson]

With the valves shut, if the pressure drops it could be the prv or somewhere else on the boiler. If it doesn't drop but drops when the valves are opened it is on the system.

 

[diycooper]

Thanks for fast reply, if it turns out to be the system and I cannot find the leak which means its probably undert the floor. I have been reading about fernox leak sealent could help, but can this do any damage or block up further do yu know ?

 

[diycooper]

I have found the problem today, It is the prv that is leaking but the water was not getting directed to outside as there was also a leak on the elbow on the copper pipe underneath the boiler from the prv. Is it pretty easy to change the prv or do I need to get someone to do this ?

 

[Agile]

I would say that its pretty easy. But then thats what I do!

But a brain surgeon probably thinks that brain surgery is fairly easy!

 

[diycooper]

I notice there is a pin is this for a quick release of the prv then replace prv then pin ?

I been looking to purchase new prv, is this correct one ?


http://www.directheatingsupplies.co...t-Pressure-Relief-Valve-(3-Bar)-|-178985.aspx

 

[diycooper]

Can no one assist me with this please.