Combi boiler Pressure setting

[DIYm1]

Guys

I have bled 2 radiators which had air in, and recharged my WB 28i junior combi boiler to 1-1.5 as recommended.
Everything's going well.

I am however curious to know what may happen if the pressure of the boiler goes beyond a certain maximum eg >3psi.
(Does excess pressure present a risk of boiler malfunctioning or blowing up for example? I am sure there must be a safety mechanism in place for such an event?)

Apologies it this is a strange question - but I am asking because when the pump comes on these days, the pressure increases to 2-2.5 (I know the increase in pressure is normal when the pump comes on...).
From the pressure dial range on the boiler, the maximum pressure the boiler should be set at is I think 2.5 or 3 (I can't remember as I am now at work).
So, if I had re-fillled the boiler to a pressure of 1.5-2, the pressure would have increased more drammatically when the pump comes on in the evening with the central heating on.

Thanks for your comments and wisdom!
This forum is fab for learning...

 

[kevplumb]

I am however curious to know what may happen if the pressure of the boiler goes beyond a certain maximum eg >3psi.

the pressure relief valve will open at 3 bar

 

[DIYm1]

Cheers for this Kev!

So if I guess this right, the valve will let water out of the sealed system to relieve the pressure so that it does not blow up?


There is a pipe that connects to the outside and the end is bent towards the house brickwork, it this the outlet for relieving the pressure? If not, what is it for?

Thanks

 

[Gilgamesh]

Hi....

I had some rads moved and the plumber accidentally over pressured the system. There was some crud in the releif valve so it failed to open fully and blew the gasket on the bottom of the pump. Beware. The boiler was a pig to strip down to get the pump out as it was housed in a kitchen unit, took a day to strip, repair and get going again. Mine now runs at just below 2 bar.

Regards.........

 

[kevplumb]

Cheers for this Kev!

So if I guess this right, the valve will let water out of the sealed system to relieve the pressure so that it does not blow up?


There is a pipe that connects to the outside and the end is bent towards the house brickwork, it this the outlet for relieving the pressure? If not, what is it for?

Thanks

yes that is the one

ignore the other dickhead

but if it blows it needs investigating as to the cause

 

[gas4you]

Hi....

I had some rads moved and the plumber accidentally over pressured the system. There was some crud in the releif valve so it failed to open fully and blew the gasket on the bottom of the pump. Beware. The boiler was a pig to strip down to get the pump out as it was housed in a kitchen unit, took a day to strip, repair and get going again. Mine now runs at just below 2 bar.

Regards.........

Just proves that all boilers must always be installed in an easily accessible location

 

[DIYm1]

Thanks a bunch guys!!