24kw heat only boiler

[Dee]

Does that size sound right for 19 rads? I'm calculating the rad size for each room when the gadget arrives see if that's an issue too

[stu w]

I would say no.

30kw required 

[Nickfromwales]

11 minutes ago, Dee said:

Does that size sound right for 19 rads? I'm calculating the rad size for each room when the gadget arrives see if that's an issue too

A 12/14kw could suffice, depending on your heat load. 24kw is a lot, 30kw to space heating is huge. 
 

What gadget do you have coming?

[JohnMo]

46 minutes ago, Dee said:

Does that size sound right for 19 rads? I'm calculating the rad size for each room when the gadget arrives see if that's an issue too

Really depends on heat loss - start with the basics do a heat loss calculation.  Then you will know what size you need.  19 radiators in a heat seize of a house and 19 radiators in a low heat loss house require different heat inputs.

 

This will give you an easy means of getting somewhere close

https://heatgeek.com/articles/heat-loss-calculations

[marshian]

3 hours ago, JohnMo said:

Really depends on heat loss - start with the basics do a heat loss calculation.  Then you will know what size you need.  19 radiators in a heat seize of a house and 19 radiators in a low heat loss house require different heat inputs.

 

This will give you an easy means of getting somewhere close

https://heatgeek.com/articles/heat-loss-calculations

 

Exactly ^ WHS 

 

Do a decent heat loss calculation yourself or pay someone to do one.

 

I had a 24kW boiler in a house with a 4 kWh heat loss at -2.5 Deg C OAT - it couldn't modulate down below 10 kWh so cycled like crazy in the shoulder seasons and wasn't that great for cycling in the middle of the winter either. 

 

When it was replaced I dropped down to a 16 kW boiler that could modulate down to 4.0 kWh - I could have gone down to 11 kW but I think HW recharge time would be longer than 30 mins which wouldn't be acceptable to me and also the smallest boiler 11 kW couldn't be range rated down.

 

Make sure if you do oversize the boiler that you at least get one that has a decent turndown (modulation) that at least mitigates the oversizing issue.