New Boiler - Old pipework

4 May 2018
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United Kingdom
Please can someone help. I am looking for some guidance on a new boiler I have had installed.

Originally I had a conventional open vented boiler on the first floor of the property and the feed and return went straight into 22mm pipe under the first floor floor. From that it branched off to
15mm f+r to 2 radiators in loft
15mm f+R to front bed and bath
15mm f+r to rear bed
15mm f +r to 2 extension beds + 2 rads in kitchen on ground floor (*)
15mm to 2 rads on ground floor (each of these legs then have a second (total 4)

I have now had a new boiler installed on the ground floor in the garage. Its a 24KW system boiler / sealed system and when it was installed they connected the 22mm feed and return to a T piece onto a 15mm pipe next to the last radiator down stairs. This left 22mm going into a T with 12 radiators in one direction and 1 in the other.

Initially they struggled to balance the system and some radiators did not heat up at all (* above) These have now been moved over to their own 15mm feed off the 22mm from the boiler but this still leaves a 22mm fed splitting between 2 x 15mm. 1 rad on 1 side, 10 on the other over 3 floors.

My question is, is this right. Should the feeds go back to the original 22mm f+r upstairs?


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Your description sounds wrong, but I can't make head nor tail of your slides. Do you have two boilers now?
You don't say how things are working now.

From your diagram, there is a short length of 22mm flow and return from new boiler that then goes down to 15mm to feed 4 rads on the ground floor. Then 15mm flow and returns come off the 4 ground floor rads circuit to feed the main 22mm flow and return run on first floor. To me that's a lash up and not how I would do it. For the system to work properly, the 22mm F and R from boiler needs to go to main 22mm F and R runs on first floor. Then all rads tee off from there in 15mm. But it sounds like you already know what really needs to be done.
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thanks for the replies. There is only one boiler. The original was on the 1 st floor. The new on the ground . Each green line is a feed and return.

Thanks for the confirmation of what I suspected.

It is sort of working. Some radiators take up to 30 minutes to get warm. My old boiler only 2:3 of the power worked hard and could make all of the radiators hot in less than 20 , just with a lot of noise.

I am probably going down the formal complaint procedure but would like to work out where I can go to get evaluation of what has been done and what needs to be done to rectify it. Is there any formal design guidance that I can refer to that is not going to cost me.
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Page 10 of the City and Guilds handbook for 1st year heating engineers ? Seriously, it's so basic it's laughable that it was done like that. Maybe try Citizens Advice. Or just show this page of replies to the installer.

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