Unvented confusions. Help a brother out.

I recently changed some taps on a system with a megaflo unvented cylinder (taps were ground floor kitchen, megaflo first floor airing cupboard in case relevant.)

The pressure at the bath taps before starting was insane. Terrifyingly forceful. He whacked them on full to show me that it caused the inlet valve in WC to let by which I changed while there.

I must admit I'm overly cautious with the parts of systems I don't work/on install and so even if there is a valve (a lever on the combination valve I believe?) to isolate mains supply to unvented I have tended to just isolate incoming mains and run hot and cold taps to change them for fear of interferring with things I don't know about.

This has worked in the past and I have asked on here in the past if this is fine to do and have been told yes (by Tamz, no less.) Please correct me if this is wrong. I did note this time it seemed to take much longer than usual for hot to finish running. I may have even done a bit of a live catch toward the end having lost patience.

Customer emailed and says his water pressure is now much less from kitchen taps (i probably should have clocked this but just check they were live as it was a late job and was losing my marbles)

I've asked him to check if it's reduced at other taps, as he didn't say. He says kitchen "taps" in email, not tap, but all he then describes is now having to wait too long to fill up a washing up bowl so maybe he means just hot? If it's cold as well wouldn't that just mean the stopcock isn't fully open? I'm pretty sure I didn't make that mistake...but who knows...

Either way I had this before couple years ago. Turned off mains, drained out hot and cold kitchen taps, turn mains back on, pressure issues at some taps and not others.

I can't remember what happened in the end. May have told them to get an unvented guy to look. But this seems silly. Seems like you should be able to turn the water off and on without needing a visited from an unvented guy afterwards.

What is likely this pressure issue and is there something I should be doing/not be doing/warning people about on these jobs? The taps were suitable for the system by the way.

Thanks

p.s. they were contract pillar kitchen taps, decent basic quality operating fine when installed so 99% sure it's not the tap(s)

Is the tap on flexi’s?

Nope, but I did fit isolation valves. But at unvented pressure that shouldn't matter...? Customer has replied that the bath taps upstairs are still fine. He didn't mention whether he is just getting this problem on one kitchen tap or both, have asked again.

Is there anything related to the unvented set-up and/or the fact I turned off the mains and opened the hot and cold taps downstairs - the cold stopping quite quickly the hot going on forever - that could cause substantially reduce flow at one set of taps (ground floor in case relevant) but leave it the same at the other (first floor)?

Because if the answer to that is no than I guess it must be the taps. But if I take them off an stick a flexi on the iso and run it into a bucket and the pressure is still pants...What next?

In case it's relevant the original pressure at the bath was literally ridiculous, like the most powerful I've ever seen. So if I go back and what he is claiming is fine at the bath still looks to have been reduced considerably then perhaps an overall reduction has occured which is mainly of annoyance at the kitchen sink....

He has now replied that it takes 10 secs to fill a washing up bowl from bath taps and now takes around 100 seconds at the kitchen, using either tap.

Check the filter inside this. If it has one and you are G3 registered

Does the tap have a softflow filter check if that's blocked

Harvest Fields said:

Check the filter inside this. If it has one and you are G3 registered

View attachment 36710

Click to expand...

Could that reduce flow at one set of taps and leave others performing fine?

markfxy said:

Does the tap have a softflow filter check if that's blocked

Click to expand...

They are off the shelf contract pillar kitchen taps. Compression valves, rubber washers, work on any system type.

Yes if both ports have been used

Interesting, sounds like the thing. I'm not G3 so would be getting someone to look after I've ruled out taps.

So in your opinion could this be my fault / related to turning off mains and draining hot and cold from kitchen? Would this have not have/been less likely to happen(ed) if I'd turned off the lever on the combination valve to drain off the hot instead? And is that what I should do in future? If so I'm hoping those valves don't leak, get stuck, do something else unexpected?

....Might I pester any passing wise heads for any further thoughts....?