Fault Finding Help Needed

[WarHammer]

Hi,

Bear with me I'm new to the forums

Basically, my home has an unvented mains pressurised heating system - in the utility room is a Glow-worm Complheat Fuelsaver 55 boiler & upstairs in a cupboard is the Tribune Premier pressurised tank with expansion vessel.

My problem is that my systems works great when heating or hotwater (or both) are switched on from the programmer - the boiler does it's job and all rads heat up nicely - the boiler pressure gauge reads normally between 2-3.5 bars when the heating/hot water is on.

When the programmer is switched off and no heating or hot water is required to be heated - the boiler pressure gauge reduces slowly (maybe 5-10hrs) to Zero pressure instead of sitting at a nice 1bar minimum.

Due to being worried by this - I use the filler loop to pump more water in to get the pressure back up to 1 bar - but the next time the programmer switches on the heating/hotwater the gauge pressure goes above 3-3.5 bar and forces the pressure relief valve to cut-in and water to dribble out of the boiler relief pipe - once it has run it's course of heating - the pressure then gradually again reduces to 0 bar over a period of hours.

Hope the above is making sense so far? - I have checked the system for obvious signs of leaks & found nothing - the pipes are not buried under the floor downstairs and run along inside the walls or under the upstairs floorboards - and no damp patches have been spotted over the weeks. I have also checked all rad valves and see no obvious leakage signs.

I can only assume that when the system is not being used - maybe the pressure in the expansion vessle needs to be looked at and is low hence not holding the normal pressure at 1 bar minimum.


As I'm no expert - I'm just guessing at the above - Can anyone out there please please give me some possible fault advice so I can get an expert in to fix it.

Many thanks in advance for your guidance

 

[Soggy_weetabix]

Your on the right track.

See posts on repressuring (or worst case) replacing expansion vessells.

Also see posts on PRV's and how to replace or re-seat.

Your system should remain at 1 - 1.2 bar cold and rise to no more than 1.8 - 2.0 when at maximum operating temperature.

Regards

David

 

[WarHammer]

Soggy,

Thx for your quick reply - maybe best for me to try & find a local plumber that is familiar with unvented pressurised systems - (easier said than done - phone 3 so far none of them work on unvented pressurised systems....seem alien to them).

On a similar vein - my boiler Glow-worm Complheat Fuelsaver 55 - is this a good one (knowing this is a subjective question) - does anyone have an emailable user manaul for one? - anyone come across any issues with them? - do they have an inbuilt pump inside them as I can't find an external pump anywhere else on the system.

Again thx for your support

 

[Soggy_weetabix]

I dont have any MI's to hand, but im sure some of the other dudes on here will be able to help you out.

Apart from the boiler failing due blocked low pressure switch and the odd blocked fan venturi I think these are pretty good boilers.

Pump is located withing boiler (bottom right side if my memory serves me correctly.)

Dont bother trying to find a plumber, look under 'Heating Engineer's' and Im sure you will find one that works on sealed systems.

Regards

David

 

[croydoncorgi]

Bear in mind there's probably nothing wrong with the U/V system and it's probably nothing to do with the pressure problem. Any competent heating engineer can work on the boiler - you only need a U/V ticket to work on the U/V cylinder itself.