Unvented cylinder - low pressure just upstairs

[wiffola]

Hi all,

We have an air source heat pump with a gledhill unvented 210l cylinder.

Unvented tank is installed upstairs above kitchen.

It was installed just over a year ago.

We have a mixer shower that has amazing water pressure.

In the last few weeks the pressure of the upstairs hot and cold taps / shower has reduced to about half. Strangely the hot and cold taps downstairs seem normal. Outside tap seems normal too.

An interesting factor is that when you have a shower the pressure is great and normal for about 10-15 seconds then it reduces down to about half. You can turn the shower off, wait 30 seconds and it will do the same - good pressure then reduces to about half.

Not sure if this is normal but after using the hot water I can hear the cold water filling the tank for 30 secs or so. Maybe longer.

I see people on forums mention PRV could be faulty or a blockage. But the scenario doesn't sound quite the same as mine.

What do people think?

Ps. I had a plumber service the heatpump and system a few weeks back which could have coincided with this issue. Is there something he could have done?

 

[buck51]

Partialy blocked gauze filter in PRV

 

[wiffola]

Thanks for the reply - are you certain on that or is it a suggestion?

Did you see my edit (think u posted as I added it): Not sure if this is normal but after using the hot water I can hear the cold water filling the tank for 30 secs or so. Maybe longer.

Thanks for your help.

 

[wiffola]

Could you possibly explain why you think that please?

Wouldn't that effect pressure to the kitchen downstairs too? Kitchen pressure is as good as ever.

Thanks