DIY Doctor

Central Heating Flow Question From old Installation

Postby bingbing » Sun Jan 05, 2020 5:01 pm

Hi, first time on this board. Have bought a 3 bed doer upper and the old gent who used to live here was a bit of a DIY enthusiast. Unfortunately quality of work was not high on his priority list so I have lots of work to redo. I may be calling in here often.

One of issues I need to sort is the piping to the rads. After having the floor boards up, cupboards out, etc I have managed to trace all the pipe work and am pretty confident I understand the flow. I have attached a rough schematic of the ground floor rad and pipe layout (rad-circuit.jpg).

Hope you can see it clearly enough. The issue is that the left two rads on the ground floor (and the two rads on the 1st floor, not shown) are feed by the return rather than the feed. Which I assume is plain wrong. I figure he ended up doing it this way as the feed and return enter the run of radiators mid way rather than at one end as is the convention so guess he got a bit stuck.

I would really like to keep the existing feed and return pipes if at all possible as they are already conveniently located and to have to move them to the beginning of the run maybe a little problematic and a lot of work. So.. I was wondering if I could incorporate a tee junction at the bottom of the vertical feed and return pipes as in the second picture(alteration-feed-return.jpg).


I know you can tee off the feed but wondered if teeing the return would cause a problem as one return would have flow into the left of the tee and the other return would have flow into the right of the tee. Would this cause any issue or would the push/suck from the circulating pump just take both sides up the vertical return without issue? Hope that is clear. Sorry for the long post and appreciate any advice given.

Regards. Bing
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Sun Jan 05, 2020 3:51 pm


Simply Build It

Postby ericmark » Mon Jan 06, 2020 12:25 pm

There are many methods, I have a pair of radiators in series in old house because the Myson fan assisted allows really hot water to return, there is no lock shield valve or TRV on a fan assisted radiator so its return goes through a second radiator in same room to cool water before return to boiler.

However radiators in series in the main need a by-pass, be it a by-pass valve or a restricted pipe, if the TRV on first three closes then nothing through last pair, and same with TRV on last pair.

Can't see anything wrong with your idea, my house has 28 mm going into 22 mm which in turn goes into 15 mm which in turn goes into 10 and 8 mm to each radiator, it has worked for last 30 years, however there is a danger that pipes could get blocked doing it that way, normal is a manifold so pipes can be removed and cleaned.

Only way is to try it, may need so method to bleed air depending on run.
Rank: Project Manager
Posts: 2461
Joined: Fri Oct 02, 2009 8:49 pm
Location: Llanfair Caereinion, Mid Wales.

Postby ericmark » Mon Jan 06, 2020 3:00 pm

Rather odd, today two people with same problem but clearly not the same people on two different forums, I would not normally link to another forum, but if the mods allow it then may be a good idea to look at what is suggested on the other forum. ... st-4525106

This is an unusual problem so I hope this time mods will permit link.
Rank: Project Manager
Posts: 2461
Joined: Fri Oct 02, 2009 8:49 pm
Location: Llanfair Caereinion, Mid Wales.

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics