Unvented Hot Water System | UK Plumbers Forums | Page 2 | Plumbers Forums

  • Welcome to PlumbersTalk.net

    Welcome to Plumbers' Talk | The new domain for UKPF / Plumbers Forums. Login with your existing details they should all work fine. Please checkout the PT Updates Forum

Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws

American Visitor?

Hey friend, we're detecting that you're an American visitor and want to thank you for coming to PlumbersTalk.net - Here is a link to the American Plumbing Forum. Though if you post in any other forum from your computer / phone it'll be marked with a little american flag so that other users can help from your neck of the woods. We hope this helps. And thanks once again.

Unvented Hot Water System

Post thread
Post reply

Discuss Unvented Hot Water System in the UK Plumbers Forums area at Plumbers Forums

R

Rachael1278

Hi, I’ve purchased a new build property and had a few issues with the unvented hot water system. I’ve now asked the developer, builder and plumber for proof of G3 certificate of the plumbers but have been told they have no need to show me this. I’ve searched the gas safe register and it’s not showing on their profile, however this doesn’t tell me definitely that they do not hold the qualification.
Anybody know what I can do to check this? Building control who signed off the house are basically unhelpful/uninterested.
 
Sort by date Sort by votes
Yes either one is fine

And it returns into the secondary port eg that pipe what goes into the cylinder from the pump
 
Upvote 0 Downvote
Hope this helps

Normally fitted to bathrooms / taps the other end of the house / far away from the cylinder as you have to run the hot tap for a while to get hot water due to the distance and the cold water in the pipe as it’s unlagged/ gone cold etc

1668531984768.png
 
Upvote 0 Downvote
You haven't got the valve I wanted to see but never mind. Once you have closed the valve Shaun asked you to, close the one on the very top of the cylinder too. There should be no water from hot taps after an initial short run off.
Open them both again once you have found out whether it stops running or not.
 
Upvote 0 Downvote
but did you reheat the cylinder for an hour?
 
Upvote 0 Downvote
And if you can keep a note on how long the boiler is fired / on
 
Upvote 0 Downvote
Racheal1256 said:
Ah, I am silly aren’t I!! I will try this again now and let you know in the morning
Click to expand...
Good morning,
So, the hot water was on from 6-7am, just tried hot water and it’s probably a little warmer but still not hot as it should be.
I did notice that the secondary return pipe where it enters the cylinder was hot to touch when brass valve under the pump was turned off but when I turn it back to open it instantly goes cold. No idea if this means anything.

Thank you.
 
Upvote 0 Downvote
Right now turn turning the lever valve off at the top of the cylinder eg the pipe leaving the centre top of the cylinder and the pump one keep that off aswell please
 
Upvote 0 Downvote
Correct but does the cylinder heat up / you have hotter water, if you do have hotter water that means water is flowing out of your cylinder all the time maybe

Also the red valve on the left wall just higher than the immersion is this open?
 
Upvote 0 Downvote
ShaunCorbs said:
Correct but does the cylinder heat up / you have hotter water, if you do have hotter water that means water is flowing out of your cylinder all the time maybe

Also the red valve on the left wall just higher than the immersion is this open?
Click to expand...
So am I to turn of the lever on the top of the cylinder, turn the boiler on, wait a while, turn the lever back to open and test the water temp from the tap?
Red valve to the left is open.
Thank you for your patience
 
Upvote 0 Downvote
Yes your testing if the cylinder will heat up at all when you re open the top lever valve after an hour and it gets instantly hot around 6” above the cylinder/ as high as you can feel there’s a problem
 
Upvote 0 Downvote
ShaunCorbs said:
Yes your testing if the cylinder will heat up at all when you re open the top lever valve after an hour and it gets instantly hot around 6” above the cylinder/ as high as you can feel there’s a problem
Click to expand...
ShaunCorbs said:
Yes your testing if the cylinder will heat up at all when you re open the top lever valve after an hour and it gets instantly hot around 6” above the cylinder/ as high as you can feel there’s a problem
Click to expand...
Ok, all turned to off and boiler set to constant. Pipes that are currently hot I’ve detailed on the attached picture. I will give it an hour and the open to lever, feel pipes again and run hot tap.

Red-hot
Orange - warm
Blue - cold
 

Attachments

  • CE58DDB5-2D71-4087-8551-4AEDF267955F.jpeg
    CE58DDB5-2D71-4087-8551-4AEDF267955F.jpeg
    376.5 KB · Views: 30
Upvote 0 Downvote
Racheal1256 said:
Ok, all turned to off and boiler set to constant. Pipes that are currently hot I’ve detailed on the attached picture. I will give it an hour and the open to lever, feel pipes again and run hot tap.

Red-hot
Orange - warm
Blue - cold
Click to expand...
ShaunCorbs said:
Yes your testing if the cylinder will heat up at all when you re open the top lever valve after an hour and it gets instantly hot around 6” above the cylinder/ as high as you can feel there’s a problem
Click to expand...
So, after an hour I turn the lever back on. Hot water draw off pipe got warmer (not red hot) to touched after a few minutes. No hot water taps have been turned on at this point.
The coil 1 pipe at the very bottom of the cylinder is now also very hot to touch and the cold feed pipe at the bottom is tepid, whereas before it was stone cold.
 
Upvote 0 Downvote
Now try running hot water
 
Upvote 0 Downvote
Right ok shut that red valve again and turn the hot water on eg heat up and leave it until it finishes eg fully heats up the cylinder you can tell this by moving the stat it’s on 60 ish now if it doesn’t click lower than this it’s fully heated
 
Upvote 0 Downvote
ShaunCorbs said:
Right ok shut that red valve again and turn the hot water on eg heat up and leave it until it finishes eg fully heats up the cylinder you can tell this by moving the stat it’s on 60 ish now if it doesn’t click lower than this it’s fully heated
Click to expand...
Ok, done that. The stat clicked when I turned it down at about the 45 marker, turned back to 60.
Will the ignition/flame light go off on the boiler when it’s fully hot?
 
Upvote 0 Downvote
Yes it’s upto around 45 dc correct
 
Upvote 0 Downvote
New posts

Similar plumbing topics

S
  • Question
hot water not staying hot in an unvented system
As Shaun said cold backfeeding through mixer...
Replies
5
Views
936
SimonG
SimonG
C
  • Question
Unvented Center cylinder no hot water
I would agree with you. This system was nee 13...
Replies
20
Views
2K
Chris68
C
U
  • Question
Unvented Cylinder Discharge pipe not to regs
They are guidelines and advice for pipe sizes...
Replies
6
Views
2K
Last Plumber
Last Plumber
Learning Plumber
  • Question
Hot water system plan
I'll start updating my drawing and post back...
Replies
14
Views
2K
Learning Plumber
Learning Plumber
T
  • Question
Hot water losing pressure
I’ve a 400 square metre 5-story house, with an...
Replies
0
Views
1K
Tony_P
T
Back
Top