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Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3805
Experience:  Heating and Controls engineer
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the water pressure on my vaillant boiler keeps droping and

Customer Question

the water pressure on my vaillant boiler keeps droping and the red knob underneath the boiler marked 3bar is wet,is this a realease valve,and does it need replaceing
Submitted: 5 years ago.
Category: HVAC
Expert:  Andrew Smith replied 5 years ago.

Andrew Smith :

Can you trace the 15mm copper pipe that exits the wall about 3ft below the flue and put a plastic bag around it

Andrew Smith :

refill the system and put it through a heating cycle and see if the bag catches any water

JACUSTOMER-nteaft4f- :

the bag did catch a little water,but now the pressure gauge fluctuates from less than one bar,and shots up to 2 bar?

Andrew Smith :

Ok, sounds like you need a new PRV to stop it dripping at less than 3bar, also there may be a problem with your pressure vessel - this is why the pressure is fluctuating when heating. This part of the boiler should cushion the boiler against the expanding water.

Andrew Smith :

It may just need the balloon inside reinflating

Expert:  Andrew Smith replied 5 years ago.
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