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Ask Andrew Smith Your Own Question
Andrew Smith
Andrew Smith, Home Appliance Technician
Category: Appliance
Satisfied Customers: 3757
Experience:  Gas cooker specialist
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We have a unistor cylinder water in roof space - fitted

Customer Question

we have a unistor cylinder for hot water in roof space - fitted last year with new vaillant boiler - we have had for some months a slow drip from external overflow and noted that when we run hot water in bathroom for either shower basin or bath that there is a whining type noise from system that takes some time to dissipate after water turned off .
are problems connected does tank need draining and refilling to get pressure reset ??
Submitted: 2 years ago.
Category: Appliance
Expert:  Andrew Smith replied 2 years ago.
It depends whether your model has an external expansion vessel (white one) attached to the cylinder?
Customer: replied 2 years ago.
yes there is an external small white cylinder at high level on right hand side of large cylinder- await your view on problems - cheers
Expert:  Andrew Smith replied 2 years ago.
Ok, if the water is dripping when it is heating the water and the pressure (on the gauge) is below 3 bar then perhaps your PRV is getting tired and needs replacing or if the gauge is reading above 3 bar then the expansion vessel may need its pressur adjusting