Poor Hot Water Pressure on Unvented

[charliejamesuk]

Hi All,

Saw a customer tonight who has a Santon Premier TP150B Unvented Cylinder with Expansion Vessel. They recently had a new kitchen fitted and since then they have very poor hot water pressure, so much so that you if turn on two hot taps at once the water just dribbles out.

Would this indicate that the Expansion Vessel needs recharging? Turning the expansion relief valve doesn't discharge any water. If so I'm struggling to find literature on this cylinder, do I charge it to 3.5 Bar like other cylinders?

Cheers
Charlie

 

[PlumbBobBob]

yes sounds like pressure problem isn't there a label on the expansion vessel with specifications etc?

steve

 

[charliejamesuk]

yes sounds like pressure problem isn't there a label on the expansion vessel with specifications etc?

steve

You'd think but no label, or its at the back of the vessel - so unreadable 🙁

 

[PlumbBobBob]

in that case i would re pressurise to 3.5 bar while keeping an eye on the expansion relief valve to make sure it isn't releasing pressure

steve

 

[justlead1]

Hi Check the incoming main / pressure / volume. The expansion vessel is only there to absorb the expanded water when heated. Also check if a filter is blocked (some unvented have them upstream of pressure reducing valve) During the kitchen installation valves would have been turned of. Were they all turned on full?

 

[charliejamesuk]

When you re-pressurise the vessel do you need to part drain the cylinder or just let the water cool?

Thanks

 

[charliejamesuk]

I spoke with Santon Technical today who said that the PRV should discharge water when tested regardless of if the Expansion Vessel is charged. The strainer needs to be cleared or the PRV replaced.

Thanks

 

[Rodreguez]

is there any taps that are not on balanced pressures i.e. kitchen cold tap supplied before pressure reducing valve? if so n thats got good pressure then probably strainer or reducing valve. if not problem is further back on main!