Can't repressurise central heating

pippip

Hi all,

Looking for a bit of help. Basically I can't repressurise my central heating system. Vokera gas boiler and mutli fuel back boiler stove. Both gas boiler and gauge in hotpress reading zero.

As you can see in the photos below I have a "T Fire" system. I bled the radiators last week and pressure dropped basically to zero. I hadn't bled them in a long while and alot of air came out.

The system was installed three years ago. I was on to the plumber who installed it and he said I should just need to turn the grey knob and thats it.......but nothing happens. It turns with what I'd call slight resistance, so not a free spining knob, moves outwards to like its opening something but no noise or feeling of running water. Typically he's "too busy" to come out to it at the moment.

The expansion tank is full and if I remove water from the system through an external outlet it refills fine from that, I just can build the pressure. There is no inlets from the mains near the gas boiler itself. From what I've read the grey knob is a low pressure inlet value, i've attached a photo of whats inside the top of it. It is fitted in the right direction according to the arrow on the side.

Am I missing something obvious or is there a chance the inlet valve is faulty? Never had to use it before so bit pissed if its faulty first time.

Tom44

Expansion tank is "Full" ??
With what and how do you know ?

( A safety question before we answer original question ).

pippip

Sorry, I may be using the wrong terms. I live in a flat roofed house so everything is in the hotpress. Its a black tank at the very top that just contains water. I can put my hand in the top of it and feel the water and ballcock. If I drain water from the stove outlet this seems to start refilling. I find it strange that it can refill from this is expected to keep a pressure?

Would I be right in thinking its an open system i have?

pippip

Hi all,

I think I have it all sorted again.

From studying my hotpress for a week, wife had lost faith so will be delighted to rub this in her face when she gets home from work :P, I worked out how it all operated and seems only the central heating side of the system is/should be under pressure. I unscrewed the black cap in photo3 and under was a spring with a bolt under it. I tried unscrewing the bolt slowly which didnt do much but when I pushed on it, while screwing back in, I discovered it released the mains water into the system. So was able to get system back to 1bar.

So the refiller tank at the top of the hotpress is only for the Stove system. I had a problem with the stove not circulating into the system when the pressure dropped but I think it must have been an airlock as when I repressurised the central heating side some air came out of the automatic air release value. Seems to operating correctly again.

As I said think its sorted but I may be back if i'm mistaken....time will tell.

Many thanks.

slystallone

Has anyone ever had a situation where the filling loop valves were both opened but there was no increase in pressure? What could be the root cause

stephenmarr

Thats an automatic filling valve.

Should be set to around 1.5 bar.

declan b

https://www.boards.ie/discussion/comment/122989920#Comment_122989920

its possible the pressure could be low coming into the house