BIASI 28S Excessive Water Pressure

sellparttime

Hi

I have just completed on my new house and moved in. I have a BIASI 28S boiler.

Water is escaping from the overflow, not excessively, but enough for a non DIY fundi to notice. I checked the water pressure gauge to find it registering 2.5 bar and know that is too high, yet I am unable to reduce it. I have bled all the radiators and drained a few liters out via the bottom radiator drain !!!! and it still remains on 2.5 bar.

I would not worry about it if it was not overflowing. Is there a setting somewhere to keep it that high or is something else the matter?

Any ideas would be welcome.

Thanks

BobProperty

I guessing because it's not my "specialist subject", but the filling loop tap is open. This may be deliberate as the water coming out of the overflow may indicate a failure or fault with a valve in the boiler. On several occasions I've seen this being done (leaving the filling tap open, that is) to keep the boiler working as it will switch off if the pressure gets too low IIRC.

thekid_2

...which suggests a leak.

Like bob says it's probably an open filling loop. Find the filling loop below the boiler, it's probably a steel braided hose affair, and make sure that both valves are off. There will be one on each end and they are normally 1/4 turn valves, hopefully clearly marked with an off position but a rule of thumb is if the slot/handle is going across the pipe it's off, if it's in line with the pipe it's on.

After making sure both valves are off, disconnect one side of the filling loop. This will break the connection, and allow you to see if one of the valves is passing slightly. (you shouldn't get soaked there will be very little water)

Keep a basin to hand and know where your main stopcock is, just in case

sellparttime

Thanks for the replies, guys.

The filling loop valves appear to be closed as the tap handles are cross ways to the pipe.

I will try to remove it to check if thay are possibly leaking. If they were leaking, I would expect the pressure gauge to slowly rise, but it stays at 2.5 bar. Oh, and I have also bled the radiators, which should reduce the pressure, but has not.

I will check when I get home tonight a post the result.

Cheers
SPT

alanobrien

If the relief valve has blown and the filling loop is closed then the pressure gauge could be stuck......seen that more than once. (Note the relief valve may be ok if its a 3 bar valve).

Be careful with the filling loop though, in my old place the valve was stuck open even though the plastic handle suggested it was shut.

A final and more drastic check would be to drain a rad
or open the drain at the bottom of the boiler.
If you do this the pressure on the gauge should fall quite rapidly.

plumb1_2

The boiler filling loop, should not be connected perminantly, it should only be used to fill the system then disconected.
When you have removed the filling loop, and it still overflows, the cause will be the PRV presure relief valve, either muck on the seating or a failed internal spring, will need replceing, Corgi engineer.