Change Heating and Hot Water System

[NewDad1]

Hello!

I am looking for advice on updating my heating system.

The current system is open vented and supports 19 rads and two bathrooms.

The boiler is in the kitchen, hot water cylinder on first floor above boiler and cold water tank in the loft.

I would be keen to:
a) Get rid or move the hot water cylinder from the bedroom so that we can get more space and turn it into a nursery.

b) Get a smaller boiler in the kitchen which will fit under 60cm counter top, as the current Mexico is huge.

Any pointers welcome.

Many thanks

 

[D_Hailsham]

19 rads and two bathrooms suggest a fairly large house.

Most modern boilers are wall mounted; do you have a place where one could be installed - it doesn't have to be in the kitchen?

If you want to get rid of the HW cylinder, you could go for a combi boiler - but that may not be agood idea if you have two bathrooms in use at the same time.

Another option is a system boiler with an unvented HW cylinder in the loft. This would replace the HW cylinder and the cold water tank in the loft and also get rid of the small F&E tank. It's similar to a combi boiler in that all water comes straight from the incoming main, but the cylinder acts as a very large buffer tank. So the water does not have to be heated instantaneously.

Combi boilers are sized for the hot water requirement. You can work this out by measuring the incoming cold water flow rate at the ktchen tap (bucket and watch). You need 2.5kw per litre per hour, with a max of 35-40kW.

System boilers are sized mainly on the heating requirement with an allowance for heating the hot water.

You can work out the heating requirement by using the Boiler Size Calculator.

Don't be surprised if this produces a result which is less than the output of your Mexico boiler. Boiler sizing has moved on from the days when the installer put in the largest one he thought the customer could afford!