Maximum Radiators Vailiant ecomax 824e

[iamlee2002]

Hi all, currently in the process of doing our upstairs out gutting the lot. We wish to add 2 additional radiators to our combi system Vailiant ecomax 824e. Looking at the manual the max heat output is 18.4kw @ 80c flow 60 return.

Not sure if you can work it out by the size of the current rads etc as i dont know the BTU value on each rad.

Currently we have the following:

800x600 double convector
1600x450 double convector
900x700 double convector
900x600 double convector
1200x600 double convector
1000x600 double convector
800x700 single convector
1100x600 towel rad

The 2 ones we wish to add would be 2x400x500 singles

would my boiler cope with these extra 2? Not sure if it can be worked on size etc, but any sort of advice would be greatly appreciated

 

[simond]

The heat required is based on the thermal requirements of the house rather than the number and type of radiators inside it.

Theoretically, you could fit 30 rads in a 2 bed semi but the heat requirement would be the same if it had 8 suitably dimensioned units.

So I'd suggest you type 'whole house heating calc' in Google, fill in the details and that'll tell you how big the boiler heating output needs to be. I'm also going to stick my neck out and say it'll easily be big enough.

If you want to do the job properly you could look up the water content for each of your radiators and compare this i the Vaillant manual for the expansion vessel size, combis often don't have enough expansion fitted, eg: you might need an external expansion vessel. Vaillant (aka Zilmet) ones are fragile at the best of times.

 

[iamlee2002]

Many thanks for the quick reply, As long as you think adding the 2 additional small ones will be ok that is good . As with thermal requirements i am insulating my house as much as poss while we gutting the upstairs so should all help . I haven't long replaced the expansion vessel in boiler had a pin hole in there some how. Even if i had to replace some of the doubles with singles i wouldn't mind It's not a big house 2 bed end terrace old stone walls, just damn cold in the winter being up the mountain doesn't help to lol, the additional rads one will be going on the upstairs landing and the other in the upstairs small wc room we installed. Thanks again for the reply m8 much appreciated

 

[David937]

Hi all, currently in the process of doing our upstairs out gutting the lot. We wish to add 2 additional radiators to our combi system Vailiant ecomax 824e. Looking at the manual the max heat output is 18.4kw @ 80c flow 60 return.

Not sure if you can work it out by the size of the current rads etc as i dont know the BTU value on each rad.

Currently we have the following:

800x600 double convector
1600x450 double convector
900x700 double convector
900x600 double convector
1200x600 double convector
1000x600 double convector
800x700 single convector
1100x600 towel rad

The 2 ones we wish to add would be 2x400x500 singles

would my boiler cope with these extra 2? Not sure if it can be worked on size etc, but any sort of advice would be greatly appreciated

You can look up the approximate outputs of your current radiators here:

http://www.stelrad.com/products/vita-series/vita-compact/

Add them all up and you'll be able to see approximately how much of the 18kW you're using and how much spare capacity your boiler has.

 

[simond]

You will not be 'using' the sum total of the radiator output. It is the heat requirement of the space that is relevant.

If you had 21Kw of radiators in a 2 bed flat, would that mean you would need a bigger boiler, David?

I assume you don't do this for a vocation?

 

[iamlee2002]

Hi all just been on screwfix site looking at the size of my rads and the kw, worked it out roughly all rads including new ones is just short of 11kw so i should be fine

Thx Simon and David

 

[David937]

You will not be 'using' the sum total of the radiator output. It is the heat requirement of the space that is relevant.

I agree, however, it was only a way for the OP to quickly check. Misleading of me to say 'using' as the heat loss may be less (or more) than what the sum of radiator outputs are.

With reference to the two bed flat question, if I ever did come accross that situation, I would look into it further before just saying that the boiler is oversized...I know, all too well, the perils of an oversized boiler.