Pressure drop in Firebird 90 Combi boiler

[JohnR-K]

The pressure drops from 2 bar to zero overnight. After reading about this problem here I have checked the PRV, no leak. Closing the butterfly valves on the central heating flow and return pipes at the back of the boiler (making sure that the central heating is set to off at both the switch and the timer) stops the pressure drop. Does this mean a leak in the pipework leading to the radiators? If so why can I not find any water anywhere, although some of the pipework is under screed?

 

[Agile]

You have done all the right things and you have confirmed there is a significant leak, perhaps within the screed if you have pipes buried there.

Finding the leak can be difficult, a thermal imaging camera would probably find it immediately.

Since you are only losing a litre or two it just soaks into the screed and does not appear at the surface for several days.

Best of luck!

Tony

 

[JohnR-K]

thank you Agile. So, how do I get hold of a thermal imaging camera?

 

[Agile]

They are not generally available although simple to make. Fire brigades usually have one for looking for bodies and the Police helicopters too for looking for warm bodies hiding in the bushes!

There is a firm that puts a gas in the system water and then detects that gas at the leak but I assume they charge a lot for their service.

Possibly a Protimeter or similar damp meter might find it too. Depends on what you have covering your cement!

Leaks are usually within a few hunded mm of a rad valve!

Tony

 

[oilman]

It might be a leaking valve that's leaking, and the water evaporates too quickly to leave a trace. Leak sealer in the system often cures the problem in my experience.

 

[Agile]

You mean a rad valve!

Thats a valid point, before digging up the concrete you should remove all the rad valve plastic knobs and look for leaks when the system is fully pressurised.

Just to be sure! I always recheck rad valves even if clients have reassured me that nothing is leaking.

Tony Glazier

 

[JohnR-K]

I tried leak sealant before posting the problem. If anything the situation got worse. I will pressurise the system and check for leaks. Thanks guys, I will post the results.

 

[onion_soup]

You have done all the right things and you have confirmed there is a significant leak, perhaps within the screed if you have pipes buried there.

Finding the leak can be difficult, a thermal imaging camera would probably find it immediately.



Best of luck!

Tony

Try here for some diy image sensing not sure it it will help locate leaks.

http://www.kailashnadh.name/docs/ir_cam/ir_cam.html

http://geektechnique.org/index.php?id=254


I can take no credit for links or more importantly losses arising from following procedures

 

[gazthepottertonengineer]

Just curious ive heard of firebird but cant think who makes them

please dont say firebird either

 

[wilhelm]

firebird

as per

 

[gazthepottertonengineer]

oh dirty smelly oil boiler

 

[oilman]

Why so? They aren't when I've sorted them out, (and yes, they are working). It's lack of maintenance that's the problem.

 

[JohnR-K]

Huzzah! well the leak finally showed itself. A stain creeping up the kitchen wall showed a leak here. I took up half the floorboards and found a leak in a feed pipe. Cut out the offending joint and replaced it. System has retained pressure for 3 weeks now.

Thanks everyone.