24kW boiler BTU Capacity

bambam26

Hi,

Looking for some advise please regarding a gas boiler size. Currenty have a Vokera Mynute 24m which has a heat output of 24kW
The house is 152 sq meters in size, 3 bed 1 bathroom with shower 1 onsuite with shower. From looking online at BTU calcucators I have worked out the I need 41500 BTU to heat the house spread over 9 rads.

The current radiatiors are to small to do this so I am going to change to larger high output ones but not sure if a 24kW boiler will be strong enough to run them or would I need a higher output boiler.
Is there a way of working out the BTU a boiler can run

Thanks

Wearb

Your boiler is over 80,000 btu.
It is unlikely your rads are undersized, the opposite is what I mostly see.

Dtp1979

bambam26 wrote: »

Hi,

Looking for some advise please regarding a gas boiler size. Currenty have a Vokera Mynute 24m which has a heat output of 24kW
The house is 152 sq meters in size, 3 bed 1 bathroom with shower 1 onsuite with shower. From looking online at BTU calcucators I have worked out the I need 41500 BTU to heat the house spread over 9 rads.

The current radiatiors are to small to do this so I am going to change to larger high output ones but not sure if a 24kW boiler will be strong enough to run them or would I need a higher output boiler.
Is there a way of working out the BTU a boiler can run

Thanks

I have 8 rads in my own house. My boiler is programmed and set to 10kw and it's more than enough to heat it. Most typical housing estate houses built in the last 10-15 year with up to 10 rads will need about 12kw

bambam26

Thanks for the replies, do you have any suggestions to my issue, I cannot get the temp in the rooms up over 18 degrees no matter how long the heating is on. Rads are balanced, well draught proofed, double glazes, front door composite type and attic well insulated and cavity wall pumped with beads. Reason I was looking at boiler And rads it take the sitting room from online calculators I need 10800 btu but rad is only capable of 6532. Room is 20ft x16ft x 8ft high with 1 standard double rad 1400x500

Wearb

bambam26 wrote: »

Thanks for the replies, do you have any suggestions to my issue, I cannot get the temp in the rooms up over 18 degrees no matter how long the heating is on. Rads are balanced, well draught proofed, double glazes, front door composite type and attic well insulated and cavity wall pumped with beads. Reason I was looking at boiler And rads it take the sitting room from online calculators I need 10800 btu but rad is only capable of 6532. Room is 20ft x16ft x 8ft high with 1 standard double rad 1400x500

Without looking at a calculator, with your level of insulation that rad should not be too far off.
What is boiler temp set to?
What is room stat set to?
Is your cylinder isolated from heating when heating only is on?
Is your boiler rated to 24kw...btw I am not sure what way that or any gas boiler is rated. Oil is my forte.

bambam26

Hi Wearb ,
Thanks for the reply
Boiler set to max which I think is 80 degrees
No room stats, no zones. Heating runs rads and hot water, I can turn a handle in the hot press for water only but not for rads only
As per the manual the max heat output rate is 24kw

Wearb

bambam26 wrote: »

Hi Wearb ,
Thanks for the reply
Boiler set to max which I think is 80 degrees
No room stats, no zones. Heating runs rads and hot water, I can turn a handle in the hot press for water only but not for rads only
As per the manual the max heat output rate is 24kw

Is your rad too hot to keep your hand on, especially bottom centre, both panels.

An oil boiler can be set to maybe 25% it's max output. I think gas has an even bigger range. So 24 kw might be setup to a max of 18kw.

Your cylinder may also be providing a short cut for circulation.

May be poor convection around rad.
.......and maybe rad is too small, but I would have someone size the required one to cross check your figures.

bambam26

Wearb wrote: »

Is your rad too hot to keep your hand on, especially bottom centre, both panels.

An oil boiler can be set to maybe 25% it's max output. I think gas has an even bigger range. So 24 kw might be setup to a max of 18kw.

Your cylinder may also be providing a short cut for circulation.

May be poor convection around rad.
.......and maybe rad is too small, but I would have someone size the required one to cross check your figures.

Rads get to hot to touch all over but more so at top, Would a plumber be the right person to ge to do a survey of rad sizes or are there home heating specialist that I would be best off getting.
Is it possible to adjust output myself or do I need an rgi to check this.

Thanks for the help, new baby on the way in a few weeks and just want the house to be comfortable for them

Wearb

If both panels of the rad are that hot then it's either too small or poor convection/radiation. I assume they have fins on both panels?

As for sizing, I would cross check a few online calculators and ask an intelligent friend to also do the same. Don't prompt him. Let him look at the room and see if he comes up with the same figures.
If he does and those suggest a larger rad, then get a plumber to fit a bigger or extra rad and ask him to check requirements before commencing.

bambam26

Thanks for your help I will get someone to do a cross check and take it from there

antoinolachtnai

bambam26 wrote: »

Thanks for your help I will get someone to do a cross check and take it from there

Good advice above. Your boiler is certainly plenty big.

I think your house is losing a lot of heat somewhere. Check for breezes and draughts. Also check that there is insulation in the attic.

bambam26

Thanks for the replys
One more question, how long should a rad stay hot for after heatinggoes of. Mine goes from to hot to touch to stone cold in about 10 minutes after the heating goes off. Trv are all set to max and I don't have room or zone thermostat.

Idbatterim

it might be struggling to keep that amount of water at 80 degrees. If you could isolate the water tank, you could see if there was a difference...

Wearb

bambam26 wrote: »

Thanks for the replys
One more question, how long should a rad stay hot for after heatinggoes of. Mine goes from to hot to touch to stone cold in about 10 minutes after the heating goes off. Trv are all set to max and I don't have room or zone thermostat.

It depends on the room temperature at the time it goes off. However as they are designed to get rid of their heat as fast as possible, it will be noticeably cooler after 10 min, even more so if the room hasn't warmed up or is poorly insulated.

Dtp1979

Check if there is a pump over run set too low

antoinolachtnai

Time for a rad to cool really depends on what the rad is made of. If the rad heats up quickly then it will also cool off quickly. Swings and roundabouts.

bambam26

Dtp1979 wrote: »

Check if there is a pump over run set too low

How would I go about checking that, only pump as far as I can see is in the boiler.

Dtp1979

bambam26 wrote: »

How would I go about checking that, only pump as far as I can see is in the boiler.

Is there a pipestat anywhere?

bambam26

Dtp1979 wrote: »

Is there a pipestat anywhere?

Not sure what that is. There is a myson trv in the hot press with a piece of wire attached to a copper pen that sits in a cutout in the tank loosely might I add