Radiators = Size Boiler Question

Vote 4 Pedro

As on the other thread I'm updating the heating,
my question here is about the rads and boiler,
If I have 15 Rads of mixed sizes as listed below what boiler would you get.

Rads Are :-

1400 x 500 Double x 2
1400 x 500 Single x 2
1300 x 500 Single x 2
1200 x 500 Double x 1
1000 x 600 Double x 1
1000 x 500 Single x 2
900 x 500 Single x 1
800 x 500 Single 1
700 x 500 Double x 1
500 x 500 Single x 1
500 x 1200 Towel Rad x 1

I might like to swap out 1 of the 1400 x 500 singles for a double
and 1 of the single 1000 for a double.

The water cylinder might be 300 litre, or a smaller cylinder with the quick re-heat coil ?

The boiler I'm thinking of getting is the Grant Vortex or Euroflame external but would I need a 50/90 a 70/90 or a 90/120

The Boiler would be outside about 16 feet and the pipes would have to go under the decking on top of the hardcore foundation then in to the house, the pipes would run in a straight line
How should they be insulated running like that.

Thanks again for advice.

K.Flyer

Have you worked out the heat requirements for each room and used the radiator manufacturer's guide to work out which is the most suitable radiator for each room?

Vote 4 Pedro

K.Flyer wrote: »

Have you worked out the heat requirements for each room and used the radiator manufacturer's guide to work out which is the most suitable radiator for each room?

Rads are in 11 years now, just looking to upgrade the boiler and cylinder and I want to make sure I get the right boiler, The plumber that does the job will point me in the right direction I hope but I would like to know what you guys would recommend, I'm just trying to avoid any mistakes, do it right first time etc.

K.Flyer

The Grant Vortex will be the Right Boiler, which size will depend on the heat and hot water requirements for the house, which needs to be calculated by the installer.
Newer radiadors may be smaller than the existing ones, but will still provide the heat outputs that are required and be more efficient.
Even though you are changing rads and boiler you still need to have the pipework power flushed and its best to have a magnetic filter fitted.

Dardania

Vote 4 Pedro wrote: »

Rads are in 11 years now, just looking to upgrade the boiler and cylinder and I want to make sure I get the right boiler, The plumber that does the job will point me in the right direction I hope but I would like to know what you guys would recommend, I'm just trying to avoid any mistakes, do it right first time etc.

K.Flyer is right - look at the heat demand first, then the radiators that are fitted.

With newer condensing boilers, they work best at lower return temperatures (e.g. that's when you can really get the greater than 90% efficiencies)

So if your room demand in kW can be satisfied with those rads, operating at flow return temps of say flow 70 return 50, int he dead of winter, that can help you choose the boiler kW output.

On the cylinder side, you need to flow at a high temp in order to store around 60C to avoid legionaries - so if you flow at 70C should be good (and if you go for the quick reheat coil, it should allow you use the delta T that gets the best out of your condensing boiler)