Low loss header
Discussion
At our new (old) house the previous owner has installed 4 x K3 rads. Probably due to the rooms being cold.
We have noticed that they don't get particularly hot, especially the front panel which often remains stone cold unless you run the heating for hours.
As such we are not getting anywhere near the heat we should. Had plumber out and they are suggesting lack of flow after checking for the usual stuff, sludge, airlocks, balancing etc. Spent 2 days on it and whilst its improved slightly, its still not even close to "hot" on the front. All 4 are like this.
They have suggested a low loss header with associated pumps etc.
I have yet to get the quote.... but I suspect its going to be a couple of grand.
I am very wary at throwing money at this - has anyone had one of these fitted?
The house is fairly large Victorian property over 3 floors. Boiler is on the top floor. The K3s are on the ground floor. So what they are saying makes sense to me and at our old house (also 3 floors) we had 2 fairly beefy pumps installed from day 1, this has none.
Due to the size of the house the boiler is a good 30ft above the lowest rad. We obviously don't know if the old rads in the same locations had issues... before our time etc.
Whole house seems to be on 15mm with some sections of 22mm, but mostly 15mm. Hard to know the layout of the pipes as they are under the floors.
Risk it or phone a friend?
We have noticed that they don't get particularly hot, especially the front panel which often remains stone cold unless you run the heating for hours.
As such we are not getting anywhere near the heat we should. Had plumber out and they are suggesting lack of flow after checking for the usual stuff, sludge, airlocks, balancing etc. Spent 2 days on it and whilst its improved slightly, its still not even close to "hot" on the front. All 4 are like this.
They have suggested a low loss header with associated pumps etc.
I have yet to get the quote.... but I suspect its going to be a couple of grand.
I am very wary at throwing money at this - has anyone had one of these fitted?
The house is fairly large Victorian property over 3 floors. Boiler is on the top floor. The K3s are on the ground floor. So what they are saying makes sense to me and at our old house (also 3 floors) we had 2 fairly beefy pumps installed from day 1, this has none.
Due to the size of the house the boiler is a good 30ft above the lowest rad. We obviously don't know if the old rads in the same locations had issues... before our time etc.
Whole house seems to be on 15mm with some sections of 22mm, but mostly 15mm. Hard to know the layout of the pipes as they are under the floors.
Risk it or phone a friend?
It's not unusual to have the boiler in the loft these days.
I've known a couple of people with townhouses.
One thing that tends to work is to fit smart TRVs and turn the ground floor rads on before any others.
If you can get the downstairs circuit hot, then you stand a a chance of not having too much 'thermal syphon' to work against.
You still have a long run of small pipe against you though.
If you can't make it work with all the other rads turned off and the ground floor rads wide open, it's goingto be major?
Proper job would be separate pump for down stairs, or move the boiler.
I've known a couple of people with townhouses.
One thing that tends to work is to fit smart TRVs and turn the ground floor rads on before any others.
If you can get the downstairs circuit hot, then you stand a a chance of not having too much 'thermal syphon' to work against.
You still have a long run of small pipe against you though.
If you can't make it work with all the other rads turned off and the ground floor rads wide open, it's goingto be major?
Proper job would be separate pump for down stairs, or move the boiler.
Some valid suggestions above but not sure moving the boiler to lower down the house will help? Surely the same amount of water needs to go upwards and is balanced by the weight of the water going downwards. The pump just moves it in the right direction and overcomes the friction, which is going to be considerable if it is on 15mm pipework.
Fitting the LLH might allow you to experiment with a larger pump which may well do the job but it is very likely that the pipework is undersized. I would be tempted to try the low loss header and larger pump, then look at the pipework. You have a large house so having the LLH gives quite a few advantages, it's not necessarily money wasted if it doesn't work. I am impressed that your chap suggested one which probably means he knows what he is doing. When I was doing my house, no one I contacted had heard of one.
I did our central heating system when we refurbed our house 9 years ago and went with a low loss header. I was concerned that the pump in the boiler would not be up to the job, it's quite high and over 4 floors, which are mostly split so heating needed on 7 different levels, 27 radiators in total. LLH is next to the boiler and the boiler has an easy job of just circulating water through the low loss header (28mm). It is isolated from thermal shocks and the internal pump has an easy life. The other side of the LLH is zoned and feeds the house, annex and HW cylinder with a large(ish) circulating pump. 28mm flow and return run up to top and to bottom of house with 22mm branches on each floor going to 15mm for 1 or max of two rads. 12 zones using evohome. Works a dream.
Fitting the LLH might allow you to experiment with a larger pump which may well do the job but it is very likely that the pipework is undersized. I would be tempted to try the low loss header and larger pump, then look at the pipework. You have a large house so having the LLH gives quite a few advantages, it's not necessarily money wasted if it doesn't work. I am impressed that your chap suggested one which probably means he knows what he is doing. When I was doing my house, no one I contacted had heard of one.
I did our central heating system when we refurbed our house 9 years ago and went with a low loss header. I was concerned that the pump in the boiler would not be up to the job, it's quite high and over 4 floors, which are mostly split so heating needed on 7 different levels, 27 radiators in total. LLH is next to the boiler and the boiler has an easy job of just circulating water through the low loss header (28mm). It is isolated from thermal shocks and the internal pump has an easy life. The other side of the LLH is zoned and feeds the house, annex and HW cylinder with a large(ish) circulating pump. 28mm flow and return run up to top and to bottom of house with 22mm branches on each floor going to 15mm for 1 or max of two rads. 12 zones using evohome. Works a dream.
PurpleFox said:
Some valid suggestions above but not sure moving the boiler to lower down the house will help? Surely the same amount of water needs to go upwards and is balanced by the weight of the water going downwards. The pump just moves it in the right direction and overcomes the friction, which is going to be considerable if it is on 15mm pipework.
Fitting the LLH might allow you to experiment with a larger pump which may well do the job but it is very likely that the pipework is undersized. I would be tempted to try the low loss header and larger pump, then look at the pipework. You have a large house so having the LLH gives quite a few advantages, it's not necessarily money wasted if it doesn't work. I am impressed that your chap suggested one which probably means he knows what he is doing. When I was doing my house, no one I contacted had heard of one.
I did our central heating system when we refurbed our house 9 years ago and went with a low loss header. I was concerned that the pump in the boiler would not be up to the job, it's quite high and over 4 floors, which are mostly split so heating needed on 7 different levels, 27 radiators in total. LLH is next to the boiler and the boiler has an easy job of just circulating water through the low loss header (28mm). It is isolated from thermal shocks and the internal pump has an easy life. The other side of the LLH is zoned and feeds the house, annex and HW cylinder with a large(ish) circulating pump. 28mm flow and return run up to top and to bottom of house with 22mm branches on each floor going to 15mm for 1 or max of two rads. 12 zones using evohome. Works a dream.
The hot water expands, it's lighter, it's not keen to go down to the ground floor rads.Fitting the LLH might allow you to experiment with a larger pump which may well do the job but it is very likely that the pipework is undersized. I would be tempted to try the low loss header and larger pump, then look at the pipework. You have a large house so having the LLH gives quite a few advantages, it's not necessarily money wasted if it doesn't work. I am impressed that your chap suggested one which probably means he knows what he is doing. When I was doing my house, no one I contacted had heard of one.
I did our central heating system when we refurbed our house 9 years ago and went with a low loss header. I was concerned that the pump in the boiler would not be up to the job, it's quite high and over 4 floors, which are mostly split so heating needed on 7 different levels, 27 radiators in total. LLH is next to the boiler and the boiler has an easy job of just circulating water through the low loss header (28mm). It is isolated from thermal shocks and the internal pump has an easy life. The other side of the LLH is zoned and feeds the house, annex and HW cylinder with a large(ish) circulating pump. 28mm flow and return run up to top and to bottom of house with 22mm branches on each floor going to 15mm for 1 or max of two rads. 12 zones using evohome. Works a dream.
It's how some systems circulated with 1950s (?) systems. It's what we had when I was very young, just a fire'stove in the dining room and 2 rads and a HW cylinder upstairs.
The pump should overcome the thermal tendency, but it's another force working against the big ground floor rads.
If all the water is at much the same temperaure, the effect would be minimised, but if you've got very hot flow and cool return, it can be significant?
A couple of houses ago, I had a concrete floor slab, and ground floor rads fed from above via microbore. It was rubbish, but the upstairs was toasty.
Turned out the motor capacitor in the pump was dying. Sorted for under a fiver, happy days!
A sober diligent person who cared enough could do the maths and see if the system should be working!
I associate LLHs with UFH, but manifolds, multiple pumps and more complex circuits with zones are all possible, the problem is how much of the house you need to rip apart to achieve an improvement.
I suspect your LLH install will be more than £2k . As previously mentioned if you can’t get those radiators hot with all the others turned off , I’d probably look at stepping up the pipe sizes from the third floor down . Is each floor zoned ? I’d expect to see 28mm flow and return from the boiler . What’s the output of the ground floor rads in kw ‘s ?
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