High Pressure in Combi Boiler

[mattd]

Anybody know why I am experiencing high pressure build up on my Glowworm Compact boiler.

It fires up ok, runs ok but after 40 mins to 1 hour the pressure is over 2.0b and it just shuts down, the pressure drops and it relights again.

I have checked the flu, cleaned the pipes, had somebody check the pressure on the boiler and all seem ok.

Is it a faulty pressure switch?

Any help would really really great

Thanks

 

[corgiman]

there is nowt wrong with it mate, you can expect some pressure increase during operation can be as much as 1br so dont worry about it#

if it builds up then dumps water out the pressure relief valve then you have a problem (expansion vessel etc...)

 

[oilman]

I suspect your cold pressure is too high anyway.

Reduce the pressure to zero and then check the air pressure in the expansion vessel. Then set the air pressure to be 1 bar for every 34 feet that the highest system point is above the lowest. This means 0.5 bar is adequate for two storeys. Then set the water pressure 0.2 bar above the air pressure. This puts the expansion vessel under minimum stress, and still allows bleeding radiators.

 

[COG]

it may help if you said what your pressure was before it rose ?, but as C said 2 bar is not too bad as a rule

 

[mattd]

Many thanks for the answers,

The original pressure was 0.7

I did as you said and dropped it dowm to 0.5

Now this is where it gets intresting because it switched itself of again after 40 mins, with out the pressure going over 2.0

It now has me thinking that it is something other than the pressure.

When it did go out ofter 40 mins, I could here it clicking to try and relight but it would not relight.

Thanks

Matt

 

[oilman]

If pressure goes that high that quickly, then your expansion vessel is suspect. Search n the forum, loads of setting/checking info.

 

[oilman]

If pressure goes that high that quickly, then your expansion vessel is suspect. Search n the forum, loads of setting/checking info.