Halstead Finest Gold Combination Boiler

[CAP99]

I have a Finest Gold Combination Boiler installed in my current home, and it has had the diverter valve replaced about 3 years ago but now it has developed a new problem.

The central heating system was filled and had a static pressure of just over 1 bar, but now when the central heating starts up the radiators all get hot but the pressure increases to above 3 bar and then starts to vent via the pressure relief valve then when the central heating cuts out the pressure falls back down but then eventually drops the pressure down to 0 bar on the pressure gauge following several cycles of heating switching on and off.

I have checked the system for any leaks etc and the system has not been modified in recent years. The hot water supply is functioning correctly it seems to just be the heating system that is affected.

Can anyone give me any clues as to what could be causing this?

 

[GasMan1965]

Sounds like the expansion vessel has gone or needs charging with air??

 

[CAP99]

Sounds like the expansion vessel has gone or needs charging with air??

Thanks

What would cause the discharge of air? and is it an easy job to recharge the expansion vessel.

 

[GasMan1965]

Sounds like the expansion vessel has gone or needs charging with air??

Thanks

What would cause the discharge of air? and is it an easy job to recharge the expansion vessel.

If the rubber diaphragm has perished then thats it really..

There is a air valve like a car tyre 1 on the vessel and you attach a pump and inflate to correct pressure.. when you find this valve, with pressure up to 1 bar cold, press in the pin to see if water comes out,, if water there then its split ,, if no water then pump it up but b4 you do let pressure back out to accommodate the air..

 

[CAP99]

Sounds like the expansion vessel has gone or needs charging with air??

Thanks

What would cause the discharge of air? and is it an easy job to recharge the expansion vessel.

If the rubber diaphragm has perished then thats it really..

There is a air valve like a car tyre 1 on the vessel and you attach a pump and inflate to correct pressure.. when you find this valve, with pressure up to 1 bar cold, press in the pin to see if water comes out,, if water there then its split ,, if no water then pump it up but b4 you do let pressure back out to accommodate the air..

Thanks

If checked the valve and when depressed there is no water just air, I assume this indicates that the diaphragm should be OK. Im not sure what pressure is currently in the expansion vessel. Does this require any special type of pump to pump the pressure upto 4bar?

 

[GasMan1965]

Just a bike pump really !!! you dont want to pump up tp much so refer to the manual ..

 

[CAP99]

Just a bike pump really !!! you dont want to pump up tp much so refer to the manual ..

I have looked at the manual but I can't find the pressure required in the expansion vessel, Have you got any ideas.

Thanks

 

[GasMan1965]

Let the pressure down to 0 then isolate the flow and return below the boiler @ the service valves , then pump up the vessel to 1 bar on the pressure gauge then open isolations below boiler and top up with water to just over the 1 bar ..

 

[ChrisR]

Look in the FAQ files

 

[CAP99]

Look in the FAQ files

I have set the pressure in the expansion vessel and started up the heating but it still has the same symptoms, is there anything else to check?

 

[CAP99]

Let the pressure down to 0 then isolate the flow and return below the boiler @ the service valves , then pump up the vessel to 1 bar on the pressure gauge then open isolations below boiler and top up with water to just over the 1 bar ..

I have set the pressure in the expansion vessel and started up the heating but it still has the same symptoms, is there anything else to check?

 

[GasMan1965]

So the vessel was ok ?

When you pumped the vessel did the gauge rise ?

 

[ChrisR]

the same symptoms,

WHich?
Pressure release valves tend to keep leaking once they've done so for a while.

 

[GasMan1965]

ChrisR... just the man

Was waiting for someone to help me here

 

[CAP99]

ChrisR... just the man

Was waiting for someone to help me here

The pressure relief valve only opens and allows the water pressure to drop once the pressure on the boiler gauge goes above 3 bar. Once the pressure has dropped off the pressure relief valve seems to reseat OK.