CH system losing pressure immediately after top up - leak?

[ashimashi]

We have moved into our current home a few months ago. It's a very old house with relatively haphazard plumbing. Things worked fine until recently when I noticed that the pressure in the sealed system is on 0.5bar and it's not heating the upstairs radiators.

Got a plumber that had done some work on this house before, and he said there was no filling loop, he connected a pipe in the attic to connect mains system to the sealed system and repressurized it.

Looked ok for a couple of days but the system completely failed yesterday, and now when you repressurize it it goes back to zero bar almost immediately (as soon as you close the filling loop).

Plumber says this is definitely due to a leak. I find it a bit strange though, as: a) It has to be an absolutely huge leak if it looses that much pressure instantly, and b)there was no problem with the system and it wasn't losing any pressure (steady at 0.5bar) until he fiddled with it!

Based on that, can anyone think of anything that your man had done to screw it up, or is it really a leak that coincidentally appeared after he did the work a couple of days ago?

There are no signs of leaks anywhere in the house btw, he thinks it's downstairs and wants to dig up the floors!

Any advice would be greatly welcome. Not the best time of year to be left without central heating!

 

[landyandy]

Need to know what make and model boiler you have.

No filling loop

Some boilers have 'built in' filling loops.

Have you got the instructions for yours.

How was it filled in the first place


Andy.

 

[ashimashi]

Thanks Andy,

1. Boiler is Glowworm Micron

2. Ref filling loop, yes that's what I asked the plumber too. He said it was there just not connected to mains, he connected it.

Just went out to check the boiler model. There is this gushing sound coming from the Expansion Vessel (the red bad thingie), sound like waves! The system is off and the valve is close so wondering where can that sound come from and would a failure in EV cause what I'm seeing?

 

[ashimashi]

btw don't have instructions for the bolier, and can't find it online!

 

[landyandy]

http://www.glow-worm.co.uk/literature/

Is there a pressure relief valve (safety valve) fitted near to the expansion vessel

Andy

 

[ashimashi]

Thanks just checked the boiler manual, doesn't seem to be an integral filling loop type!

The PRV is lovated very close to the boiler and relatively close to the EV, about 2 ft away from it, in the same boiler house!

 

[landyandy]

Is the prv discharging

 

[ashimashi]

nope, no discharge from PRV.

 

[landyandy]

It's sounding like a burst.

Maybe a plastic fitting has 'popped off'.

Boiler house freezing

Not sure about the gushing sound with the system off, maybe the pump is still running

 

[ashimashi]

thanks!

Would a burst of that size not be easy to hear though? Can't here anything from under the floors when I have the filling valve open.

Boilder house is probably freezing alright, it's been -8 here a couple of night ago and the boiler house is outside and not insulated at all!

Do you think I need to turn the pump off to prevent further damage?