Combining heating extension and old part of house

11
Posted 9th AugEdited by:"KEEP_IT_TEA"
Hi all,

So i have had two different plumbers with two very different opinions - so i really hope someone could add some clarity - thanks in advance

Many years ago my house had an extension - the downstairs was given planning permission the upstairs wasnt.

Despite many appeals the upstairs was never given planning permission.
reluctantly i decided to extend just the downstairs.

The situation currently is i have a very big downstairs but a very small upstairs (two average bedrooms and a boxroom).

Ultimately we have decided to incorporate a ensuite-bedroom downstairs for my elderly mum - sacrificing one of the three living rooms. Luckily the mess/building work is confined to just the one room.

so herein lies the problem

When the extension was done our plumber at the time kept the old part of the house on the old boiler system (15mm copper pipes) and the new extension on a new boiler (22mm copper pipes).

our home has two climate zones, so the new extension downstairs is warm and cozy, but the minute you head upstairs you walk into antartica and vice versa.
Obviously far from ideal

Iv asked two plumbers if it would be possible to connect all the radiators onto just one boiler 8 in new extension and 7 from old part of the house

First plumber said yes possible - but the boiler would have to work, pump harder - but do-able.

Second plumber flat out said the old part of the house wont get enough heated water pushed through radiators hence cold spots.

The current situation - is far from ideal. Just want a heating system to heat the house as a whole.

Can anyone help with some advice

Thanks in advance
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11 Comments
15 radiators is a lot. are you going to replace the existing 2 boilers with a new one?
I suggest you get a 3rd opinion. Ask members for a recommendation. You just need to balance the radiator valves (which will not be 22mm)
Edited by: "Willy_Wonka" 10th Aug
Observation:
"...the minute you head upstairs you walk into antartica..."

The above statement suggests the original heating design was under-spec'd or the system is so sludged-up it has simply lost a reasonable proportion of its ability to transfer heat from the rads to the living space.
You could even suggest that the older section of the property is not as insulated as the newer extension, but again that would be an under-spec issue of failing to allow properly for losses.
aelheating.com/blo…ts/
Multi Zone control would be preferable .... each zone would need a non-TRV radiator to give feedback to the thermostat.
The larger pipe section may need some restriction to avoid it taking too much of the feed, as then the other sections would have significantly reduced performance when the the larger bore section has main valve and a majority of TRV open.

I wonder if two pumps would be a feasible option?
Edited by: "matth9999" 10th Aug
Get a few more plumbers round see what they say, go with the majority, although you explained it well, when looking at it they might see other issues/problems. Get free quotes from a couple of the bigger firms as well.
1. Forget the plumbers.
2. Call a few (at least 3) heating engineers.
3. Describe the symptoms and problems plus the current heating architecture
4.. Describe your requirement.
5. DO NOT suggest any solution.
6. Ask for quoted options (cheap, mid and best)
Currently have a combi or system boiler with tank? A new high kw combi could supply that many rads but isnt the best solution.

A new 30kw+ system boiler with 250 litre + tank will do it better. From the boiler, the pipe can split in two, one going to upstairs and one downstairs. You would have a zone valve on both pipes just after the split which is controlled by thermostat downstairs and one upstairs allowing you to just supply heating to one, the other or both simultaneously. The boiler pump should be more than sufficient and the radiators upstairs may have issues because they are blocked with sludge or need balancing. If you do this, powerflush whole system first.
Call WB tech support. They will have some info but more importantly, point you at a proper heating engineer. (S)he will recommend WB product but you will have a better response than talking to plumbers.

15 rads is not a lot. A 27 or 30 WB boiler will Likely do it. Allow 3kwh for living rooms (Per rad if a large room) and bathroom, 1.5kwh for bedrooms, kitchen etc and Add 3kwh for HW. That’s the size of boiler you need
I have unfortunately some experience of this issue. Our house is 2 old houses knoked into one with a sizable extension added later. We have never successfully integrated to whole system despite using different plumbers and a heating engineer. The engineer wanted to pressurise the the system with an expansion vessel but we were reluctant due to the age of a lot of the piping and had already had a pipe burst. The only thing that improved matters was a more powerful circulator which improved the hot water flow to the colder radiators. The real cure is to rip it all out and start from scratch, but too expensive to do.
airbus33010/08/2020 11:22

I have unfortunately some experience of this issue. Our house is 2 old …I have unfortunately some experience of this issue. Our house is 2 old houses knoked into one with a sizable extension added later. We have never successfully integrated to whole system despite using different plumbers and a heating engineer. The engineer wanted to pressurise the the system with an expansion vessel but we were reluctant due to the age of a lot of the piping and had already had a pipe burst. The only thing that improved matters was a more powerful circulator which improved the hot water flow to the colder radiators. The real cure is to rip it all out and start from scratch, but too expensive to do.


when i bought my house some years ago, i got the gas engineer to come in and chuck out the whole central system and start anew. they took all the old pipes out and put in new pipes throughout, together with the most powerful combination boiler available. it costs a lot of money but i thought it was worthwhile to do as the property was an old victorian house that had 3 storeys and a cellar, so effectively 4 storeys.

when i bought it, it had 2 heating systems, one boiler for the central heating and one for the hot water. those were thrown out and a new combination boiler put in. the new system worked.

when we bought our house a couple of years ago, there was a convential boiler with a tank. i got that chucked out and got the gas engineer to put in a new combination boiler. however, i didn't chuck all the pipes out like i did before. the engineer said that the pipework was very poor, in the sense it went all over the place and did not follow a reasonable route so it must have been added to in a haphazard way.

the house is a big house, and it was blooming freezing the first winter we were here. i then chucked most of the radiators out and got the gas engineer to put in new radiators. that has made a huge difference. i initially thought maybe we didn't get a powerful enough boiler, but it turns out it was the old radiators that were not producing enough heat. i did pay for a full powerflush of the system when i got the new combination boiler installed, but that wasn't enough.

OP - you could try replacing all the old radiators with more powerful new ones and you could try replacing the old boiler that supply the old house part with a more powerful new one as well.

otherwise as airbus says, you may need to start again from scratch if you want a decent system.
Long term the gas bill will surely be lower with one high capacity boiler. And zoned temperature setting would mean its not trying to heat all rads at the same time.
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