Heating upgrade and BTU calcs

johnnyboy08

Hi,

I'm looking to do a heating and controls upgrade on a 15 year old house and am looking for some advice to make sure I'm on the right track.

The house has a Firebird SuperQ 85/115 in the utility room which feeds 9 rads downstairs and 6 upstairs. Of the 9 downstairs ones, there are 2 in the sitting room making me think that the existing boiler isn't producing enough heat for 1 rad in that room or balancing is off somewhere.

The plan to upgrade would be to zone the heating as downstairs, upstairs and water only using a condensing boiler.

I've calculated the total BTU requirement for the house as 44,000 (nearly 13 kWh) but don't know how much to assign to the cylinder if all zones are switched on. Some say 10,000 BTU, while other 20,000 BTU.
The cylinder is insulated copper around 4' 6" tall and I'd be looking to have water only for around an hour a day.

As for condensing boiler. I think the Grant Vortex 50-90 which outputs 15-26kWh would do the job perfectly, the unknown being the hot water heating requirements. Would that suit?

For controls, the preference would be to have something remotely controlled via wifi and router port opening or 3/4G and digital thermostats upstairs and downstairs (no preference for thermostat on cylinder). Has anyone any experience with remote controls and how they find using them?

Thanks.

Dtp1979

johnnyboy08 wrote: »

Hi,

I'm looking to do a heating and controls upgrade on a 15 year old house and am looking for some advice to make sure I'm on the right track.

The house has a Firebird SuperQ 85/115 in the utility room which feeds 9 rads downstairs and 6 upstairs. Of the 9 downstairs ones, there are 2 in the sitting room making me think that the existing boiler isn't producing enough heat for 1 rad in that room or balancing is off somewhere.

The plan to upgrade would be to zone the heating as downstairs, upstairs and water only using a condensing boiler.

I've calculated the total BTU requirement for the house as 44,000 (nearly 13 kWh) but don't know how much to assign to the cylinder if all zones are switched on. Some say 10,000 BTU, while other 20,000 BTU.
The cylinder is insulated copper around 4' 6" tall and I'd be looking to have water only for around an hour a day.

As for condensing boiler. I think the Grant Vortex 50-90 which outputs 15-26kWh would do the job perfectly, the unknown being the hot water heating requirements. Would that suit?

For controls, the preference would be to have something remotely controlled via wifi and router port opening or 3/4G and digital thermostats upstairs and downstairs (no preference for thermostat on cylinder). Has anyone any experience with remote controls and how they find using them?

Thanks.

Yes 50/90 set at 50 should suit you. There's loads of wifi controls out there now but honestly they're just a novelty unless you're a pilot whose out of the country most days

John T Carroll

johnnyboy08 wrote: »

I've calculated the total BTU requirement for the house as 44,000 (nearly 13 kWh) but don't know how much to assign to the cylinder if all zones are switched on. Some say 10,000 BTU, while other 20,000 BTU.

I have a 0.65 M2 coil in my 150 Litre cylinder and with all zones on line and a average boiler water (coil) temperature of 70C the coil will absorb between 5.35 Kw (18,250 Btu) when heating water from 20C and 1.8 Kw (6140 Btu) when water temperature is around 55C so assigning 20,000 Btu should cover most scenarios, in my opinion.

Wearb

Due to zoning, and well insulated cylinders (that allow cylinders to be heated outside of house heating times or in conjunction with one heating zone), I have heard plumbers say that the cylinder no longer needs to be considered when sizing modern systems. I am inclined to agree with that.