Central heating losing pressure all the time

[MT Poole]

Every two weeks or so I have to go and top up the system because the hot taps are running cold. Boiler display is flashing 0.6 bar and I fill up to 1.3. I've had an engineer look inside the boiler and he can't see anything wrong. I've checked the pipes all over the house and cannot see any obvious leaks. Is it worth replacing the radiator valves? They aren't that old and it seems to be quite a lot to be losing all the time for it to be a small leak but I can't think what else it could be.

 

[fowlerboi]

Get a decent engineer to isolate the boiler and test. It will then be obvious if its the system or the boiler. From that point its fairly easy to figure out. If its the boiler it will likely be the Heat exchanger or the pressure relief, if its the heating system and you're not showing any water on ceilings then it will probably be under the ground floor somewhere (do the obvious checks and make sure you've not got green crusty lumps around the pipework you can see in the airing cupboard/boiler/radiators. It could possibly be a pressure relief that's separate from the boiler instead

 

[PSxxxxxx]

It's always the pipework you can't see that's the problem

 

[MT Poole]

An update after weeks of isolating each radiator one by one, and checking all the pipework, I've been waiting for a decent spell where the wife won't be moaning about how cold it is to shut the flow and return valves under the boiler and it still went from 1.5 to 0.7 bar in just over a week. I have looked with a torch inside the boiler as best I can without touching anything, but I cannot see any signs of leaking. I'm stumped. Boiler is a Vaillant Eco Tec Pro 28, fitted 2015.

 

[ShaunCorbs]

Isolating each rad was a waste of time you would see if one was leaking

Expansion vessel and prv probably so needs a gas engineer

 

[MT Poole]

The PRV pipe is dry on the outside so unlikely to be that.

It's took me about 100 attempts just to post the above sentence. For some bizzare reason it won't let be post the word that formed by combining out and let.

 

[ShaunCorbs]

The PRV pipe is dry on the outside so unlikely to be that.

It's took me about 100 attempts just to post the above sentence. For some bizzare reason it won't let be post the word that formed by combining out and let.

Try running the central heating and then after an 30 mins to an hour watch the prv

 

[MT Poole]

Try running the central heating and then after an 30 mins to an hour watch the prv

Done that many times now, there is nothing coming out of it.

 

[ShaunCorbs]

Done that many times now, there is nothing coming out of it.

Need to isolate the boiler then if it drops new boiler time

 

[MT Poole]

Need to isolate the boiler then if it drops new boiler time

It has dropped after isolating. Bugger