Heat pump leaking

PaoloGotti

Hi,

My heat pump is dripping at the pressure relief valve, only when pump running. Valve is rated at 3 bar and on inspection seems to have good spring compression and no gunk (I cleaned it).
Water pressure showing at inlet is only 1.5 bar for the system.

Is it most likely a faulty valve or could it be something else? (Expansion pressure?)

Thanks
Paolo

Outkast_IRE

It could possibly be system expansion when heating. Do you have an expansion vessel somewhere on the system , have you checked its not full of water ?

PaoloGotti

Outkast_IRE wrote: »

It could possibly be system expansion when heating. Do you have an expansion vessel somewhere on the system , have you checked its not full of water ?

There is a vessel in the attic. I have noticed a gurgling from it when pump runs down. Sign of a lack of pressure? What should the pressure be set to if the inlet pressure is 1.5 bar?

Thanks

Outkast_IRE

PaoloGotti wrote: »

There is a vessel in the attic. I have noticed a gurgling from it when pump runs down. Sign of a lack of pressure? What should the pressure be set to if the inlet pressure is 1.5 bar?

Thanks

Often around 1 bar but first you need to check if its working or not. Bit of a guide here for boiler ones, but same thing

https://www.viessmann.co.uk/heating-advice/what-is-an-expansion-vessel

PaoloGotti

Outkast_IRE wrote: »

Often around 1 bar but first you need to check if its working or not. Bit of a guide here for boiler ones, but same thing

https://www.viessmann.co.uk/heating-advice/what-is-an-expansion-vessel

Thank you that article is helpful.

I don’t understand however how a expansion tank set to 1 bar would not be immediately flooded by a water pressure of 1.5 bar??

Outkast_IRE

PaoloGotti wrote: »

Thank you that article is helpful.

I don’t understand however how a expansion tank set to 1 bar would not be immediately flooded by a water pressure of 1.5 bar??

Where is the pressure guage on the system - Is it on the Ground Floor ?
Secondly is the guage your reading on the heating system side or on the mains water supply to the heating system?

If the guage is on the heating system side is the system cold when you took this reading ?

Where is the Expansion Vessel ? First Floor or Ground floor also ?

There are numerous factors in setting the vessel pressure. In the heating system itself 1bar pressure is typical when the system is cold .

PaoloGotti

Thanks for your reply.

The gauge is at the auto fill valve in upstairs hot press. So it is the heating side pressure and is stickered 1.5 bar. The gauge’s movable red pointer was is set to 1.5 bar. If I let the leak occur with full valve closed the pressure drops, proving it’s heating side reading. When I open the valve again it fills to 1.5 bar. All when water at cold temp. At hot temp the pressure can rise to 1.8 bar or so.

The expansion tank is in the attic, directly above fill valve, only about 7/8 foot above it.

Outkast_IRE

PaoloGotti wrote: »

Thanks for your reply.

The gauge is at the auto fill valve in upstairs hot press. So it is the heating side pressure and is stickered 1.5 bar. The gauge’s movable red pointer was is set to 1.5 bar. If I let the leak occur with full valve closed the pressure drops, proving it’s heating side reading. When I open the valve again it fills to 1.5 bar. All when water at cold temp. At hot temp the pressure can rise to 1.8 bar or so.

The expansion tank is in the attic, directly above fill valve, only about 7/8 foot above it.

If the pressure when the system is warm only rises from 1.5 to 1.8 bar , then that would be within the acceptable amount and the expansion vessel is probably ok.

you may just need to replace the pressure relief valve with one of an identical rating.

PaoloGotti

Outkast_IRE wrote: »

If the pressure when the system is warm only rises from 1.5 to 1.8 bar , then that would be within the acceptable amount and the expansion vessel is probably ok.

you may just need to replace the pressure relief valve with one of an identical rating.

Thanks

I put a gauge on at the relief valve and pressure is 2 bar there (ground level). Expansion tank within heat pump itself was only set to 1 bar so I increased it to 2 and now the leak is gone.