Boiler Question
Discussion
Evening, I’m looking for some thoughts on our boiler.
We have a three-level house, with five bedrooms and five bathrooms, 19 radiators altogether.
The boiler is an Ideal Logic System s24, with the usual unvented storage tank.
One thermostat controls the ground floor, while the one on the second floor runs that and the top floor .
We’re finding that the top floor is never really getting to temperature, with the last radiator in the run merely being warm towards the bottom, and not really emitting the same heat as others.
There is no trapped air in the system, so we’ll check the balancing tomorrow.
We’ve messed around with boiler glow temperature and radiator settings, without changing too much on the top level.
The boiler is 24kW - do you reckon this is simply insufficient for our needs, that we need a more powerful boiler?
It’s a new build by the way.
We have a three-level house, with five bedrooms and five bathrooms, 19 radiators altogether.
The boiler is an Ideal Logic System s24, with the usual unvented storage tank.
One thermostat controls the ground floor, while the one on the second floor runs that and the top floor .
We’re finding that the top floor is never really getting to temperature, with the last radiator in the run merely being warm towards the bottom, and not really emitting the same heat as others.
There is no trapped air in the system, so we’ll check the balancing tomorrow.
We’ve messed around with boiler glow temperature and radiator settings, without changing too much on the top level.
The boiler is 24kW - do you reckon this is simply insufficient for our needs, that we need a more powerful boiler?
It’s a new build by the way.
A 24kw boiler is not sufficient for 19 radiators and the probably being made worse by the distance of 3 floors. You need a boiler between 32 and 40kw. Their own website says so....
https://idealheating.com/tips-and-advice/what-size...
https://idealheating.com/tips-and-advice/what-size...
Do the top floor radiators get hot if you turn the downstairs thermostat off so your boiler is focusing on just the top 2 floors?
How many radiators do you have if you discount the ground floor radiators?
Does water come out of the bleed nipples on the top floor? I'm guessing it will be a sealed system, is the pressure set correctly?
How many radiators do you have if you discount the ground floor radiators?
Does water come out of the bleed nipples on the top floor? I'm guessing it will be a sealed system, is the pressure set correctly?
craigjm said:
A 24kw boiler is not sufficient for 19 radiators and the probably being made worse by the distance of 3 floors. You need a boiler between 32 and 40kw. Their own website says so....
https://idealheating.com/tips-and-advice/what-size...
Did you miss the bit in the OP that said “modern house” https://idealheating.com/tips-and-advice/what-size...
If a modern house with 3 floors 5 bed and 5 baths needs more than 24 kW boiler it’s bloody poorly built house
Boiler manufacturers always say you need more - if I put my details in for a boiler spec it comes back 24kW - at -2.4 I need 4.5 kW add a 5 kW for water demand and I still am miles from 24kW
B'stard Child said:
craigjm said:
A 24kw boiler is not sufficient for 19 radiators and the probably being made worse by the distance of 3 floors. You need a boiler between 32 and 40kw. Their own website says so....
https://idealheating.com/tips-and-advice/what-size...
Did you miss the bit in the OP that said “modern house” https://idealheating.com/tips-and-advice/what-size...
If a modern house with 3 floors 5 bed and 5 baths needs more than 24 kW boiler it’s bloody poorly built house
Boiler manufacturers always say you need more - if I put my details in for a boiler spec it comes back 24kW - at -2.4 I need 4.5 kW add a 5 kW for water demand and I still am miles from 24kW
Balance the system and then see how it goes. If there are rooms you dont really use then turn those down on the rad stat to a lower level so they are not taking heat unless its really needed.
I bought a dual input digital thermometer which shows in and out flow temp handy thing, so you can get your drop on the rad set up quicker.
Proper plumbers ones are £50+ but you can get one on ali express for less than £20.
I bought a dual input digital thermometer which shows in and out flow temp handy thing, so you can get your drop on the rad set up quicker.
Proper plumbers ones are £50+ but you can get one on ali express for less than £20.
craigjm said:
I actually did miss the last sentence yes well spotted
No worries - I was also working on an assumption that the boiler is the OE fitment so probably more than capable of heating the whole house 
Which leaves
Low pressure in system
Pump speed/head
Balancing issue from either
lock shield valves getting a bit of magnatite build up
Or more likely
A few of the lower floor rooms have been decorated and the rads been off the wall and not been reset to original position
That’s where my money is going
Lincsls1 said:
Do the top floor radiators get hot if you turn the downstairs thermostat off so your boiler is focusing on just the top 2 floors?
How many radiators do you have if you discount the ground floor radiators?
Does water come out of the bleed nipples on the top floor? I'm guessing it will be a sealed system, is the pressure set correctly?
12 radiators on the top two floors, air bled.How many radiators do you have if you discount the ground floor radiators?
Does water come out of the bleed nipples on the top floor? I'm guessing it will be a sealed system, is the pressure set correctly?
The pressure is correct.
It sounds like a balancing issue.
Possibly the layout of the system does not favour the top floor.
Do you have a lot of TRVs or just the two thermostats?
My Mum had a modern Ideal Combi, don't know how similar the system boiler would be, but the combi seemed to default to load compensation, so would turn the flow temp down if the target temp was not far above room temp. It also seemed to 'automatically' play with the pump speed.
I don;t think the installer understood it, he was certainly not great at explaining it to mum. I believe it was basically OpenTherm, using Ideal's own programmer/stat.
Does the system have a bypass valve or a 'permanently on' towel rail or rad? This may need looking at, if it's taking too much flow and starving the top floor.
Also, if the system has weather compensation, this may be turning things down too much, so the thermostats and TRVs are not in control. Possibly the top floor rads are smaller relative to the demand on them than the other floors?
I would start with the balancing, note the current lockshield settings in turns/fractions of turns from closed, then set the thermostats to high target temp and check you can get good flow to each rad.
If you poke around the menu screens on the boiler, you should be able to see value for a lot of variables.
Sometimes the problem is as vague as 'the thermostat feels a different temperature than you do'.
If the thermostat senses warmth because it's in a draught heated by a rad, it won't represent the general air temperature.
I got some digital thermometers and looked at how different parts of the main room warmed up to find a good location for the 'stat'.
These boilers are stuffed with over-complex software, which might score them an extra point of efficiency in the lab, but needs to be understood and worked around in some real houses. Adding third party controls can also complicate things. They also seem to change their software more often than their pants.
Possibly the layout of the system does not favour the top floor.
Do you have a lot of TRVs or just the two thermostats?
My Mum had a modern Ideal Combi, don't know how similar the system boiler would be, but the combi seemed to default to load compensation, so would turn the flow temp down if the target temp was not far above room temp. It also seemed to 'automatically' play with the pump speed.
I don;t think the installer understood it, he was certainly not great at explaining it to mum. I believe it was basically OpenTherm, using Ideal's own programmer/stat.
Does the system have a bypass valve or a 'permanently on' towel rail or rad? This may need looking at, if it's taking too much flow and starving the top floor.
Also, if the system has weather compensation, this may be turning things down too much, so the thermostats and TRVs are not in control. Possibly the top floor rads are smaller relative to the demand on them than the other floors?
I would start with the balancing, note the current lockshield settings in turns/fractions of turns from closed, then set the thermostats to high target temp and check you can get good flow to each rad.
If you poke around the menu screens on the boiler, you should be able to see value for a lot of variables.
Sometimes the problem is as vague as 'the thermostat feels a different temperature than you do'.
If the thermostat senses warmth because it's in a draught heated by a rad, it won't represent the general air temperature.
I got some digital thermometers and looked at how different parts of the main room warmed up to find a good location for the 'stat'.
These boilers are stuffed with over-complex software, which might score them an extra point of efficiency in the lab, but needs to be understood and worked around in some real houses. Adding third party controls can also complicate things. They also seem to change their software more often than their pants.
OutInTheShed said:
It sounds like a balancing issue.
Possibly the layout of the system does not favour the top floor.
Do you have a lot of TRVs or just the two thermostats?
My Mum had a modern Ideal Combi, don't know how similar the system boiler would be, but the combi seemed to default to load compensation, so would turn the flow temp down if the target temp was not far above room temp. It also seemed to 'automatically' play with the pump speed.
I don;t think the installer understood it, he was certainly not great at explaining it to mum. I believe it was basically OpenTherm, using Ideal's own programmer/stat.
Does the system have a bypass valve or a 'permanently on' towel rail or rad? This may need looking at, if it's taking too much flow and starving the top floor.
Also, if the system has weather compensation, this may be turning things down too much, so the thermostats and TRVs are not in control. Possibly the top floor rads are smaller relative to the demand on them than the other floors?
I would start with the balancing, note the current lockshield settings in turns/fractions of turns from closed, then set the thermostats to high target temp and check you can get good flow to each rad.
If you poke around the menu screens on the boiler, you should be able to see value for a lot of variables.
Sometimes the problem is as vague as 'the thermostat feels a different temperature than you do'.
If the thermostat senses warmth because it's in a draught heated by a rad, it won't represent the general air temperature.
I got some digital thermometers and looked at how different parts of the main room warmed up to find a good location for the 'stat'.
These boilers are stuffed with over-complex software, which might score them an extra point of efficiency in the lab, but needs to be understood and worked around in some real houses. Adding third party controls can also complicate things. They also seem to change their software more often than their pants.
Possibly the layout of the system does not favour the top floor.
Do you have a lot of TRVs or just the two thermostats?
My Mum had a modern Ideal Combi, don't know how similar the system boiler would be, but the combi seemed to default to load compensation, so would turn the flow temp down if the target temp was not far above room temp. It also seemed to 'automatically' play with the pump speed.
I don;t think the installer understood it, he was certainly not great at explaining it to mum. I believe it was basically OpenTherm, using Ideal's own programmer/stat.
Does the system have a bypass valve or a 'permanently on' towel rail or rad? This may need looking at, if it's taking too much flow and starving the top floor.
Also, if the system has weather compensation, this may be turning things down too much, so the thermostats and TRVs are not in control. Possibly the top floor rads are smaller relative to the demand on them than the other floors?
I would start with the balancing, note the current lockshield settings in turns/fractions of turns from closed, then set the thermostats to high target temp and check you can get good flow to each rad.
If you poke around the menu screens on the boiler, you should be able to see value for a lot of variables.
Sometimes the problem is as vague as 'the thermostat feels a different temperature than you do'.
If the thermostat senses warmth because it's in a draught heated by a rad, it won't represent the general air temperature.
I got some digital thermometers and looked at how different parts of the main room warmed up to find a good location for the 'stat'.
These boilers are stuffed with over-complex software, which might score them an extra point of efficiency in the lab, but needs to be understood and worked around in some real houses. Adding third party controls can also complicate things. They also seem to change their software more often than their pants.
Sorry - I suffer from premature sending!!
What a detailed. helpful reply, you’ve given me lots to think about.
TRVs on all the radiators.
Your comment about the thermostat not feeling the temperature we feel is a good one - they are both located in warmer corners, so would they be thinking room temperature was reached too early?
The thermostat on the second floor shuts off when the target is reached there, leaving the top floor noticeably cooler.
We will try balancing shortly and go from there.
Thanks again for your help.
What a detailed. helpful reply, you’ve given me lots to think about.
TRVs on all the radiators.
Your comment about the thermostat not feeling the temperature we feel is a good one - they are both located in warmer corners, so would they be thinking room temperature was reached too early?
The thermostat on the second floor shuts off when the target is reached there, leaving the top floor noticeably cooler.
We will try balancing shortly and go from there.
Thanks again for your help.
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