Pressure is Zero? - How?

[coldfused]

My dad currently owns e.l.m. leblanc GVM 4.20 boiler (10 years old) and we moved recently into the conservatory because the "flue" needs to be connected to the outside.

We moved it into its news position and fixed a new radiator into the conservatory, my dad filled the system, removed all the air leaks from each radiator, pressure remains at zero, but none of us have a clue.

I've read in the forums that I should check the expansion vessel for pressure or to see if there is any water leaks, but the expansion vessel is inaccessible (place behind the boiler) and wouldn't really know how to check it if it leaks. The pump works properly.

Its a Combi Boiler but we only use it for Central Heating and not for the taps as we have a different boiler for domestic water.

I've read that the pressure loss could be due to a leak, but it looks really unlikely, but then again we have added more pipes to the system - but also it could be due to a faulty pressure safety valve, but wouldn't really know if it was faulty or not.

The pressure gauge which shows how much pressure in bars reads zero, and it goes before the pressure saftey valve(PSV).

(from burner)WATER ----> PRESSURE GAUGE(bars) ----WATER----> PSV --> WATER OUT (into the central heating system)

Is that correct? So could there be a problem before the gauge, thats why it reads zero?

Again I'm not to sure - niether does my dad - any help would be excellent!

 

[oilman]

It reads zero because it's either broken, or there IS no pressure.

If the expansion vessel is inaccessible, you need to make it accessible for annual maintenance, or add another one which is accessible. You can never have too much expansion space. Not being able to check the air pressure in the expansion vessel is a serious problem. Failed diaphram = no expansion space = boiler, pipe work and radiators have o take up the expansion. This will lead to premature failure probably of the boiler. Expensive, when £50 spent on an expansion vessel would solve it.

 

[heraldica]

coldfused should check that the thermo/mano is firmly clipped in place.
On our GVM 4.20 the reading was approx zero even though the system was obviously pressurised and holding its pressure, but I later discoverd that the gauge had been pushed slightly sideways maybe by adding or removing the case. Remove the circular clip, press the gauge in firmly, and replace the circular clip!

 

[Agile]

You have replied to a posting almost THREE years old!!!

Their Elm Leblanc has hopefully been replaced by now!

Tony