New Extension - Extending CH

[sv969]

Hi,

Ive had a new extension built and the Building Regulations Notes on the architect plans state the following (with respect to the heating system)...

"Extended existing heating system to include for new timing controllers and room thermostats and all new radiators should be fitted with thermostatic valves..."

The main house had a CH refit a few years ago and is a pressurised system using a Smartfit controller and one main timing controller/thermostat situated in the hall.

My question is...Do the building regs require that each of the new rooms needs its own timing controller and thermostat, as well as the radiator valves? Or is this not merely put there to ensure that the existing system is brought up to date?

Thanks in advance.

SV969

 

[dextrous]

Depends on the size of the extention. If the new rooms have been plumbed in as a new heating zone (with port valves to distinguish between the existing building and the new one), then part of the interlock (basically control design) would require different zone controls.

TRVs as you know are a standard modern design feature to prevent excessive use of fuel.

However, although the new zone (several rooms) may require separate timing controls, it would not mean every room, unless each room has a valve which controls it, which is highly unlikely unless you have had underfloor heating installed here and there.

 

[sv969]

Thanks for the reply,

The extension is basically, a new reception room, new bedroom and a utility. The exisiting system isn't zoned, being on one circuit.

 

[dextrous]

If the new rooms are extended from the existing flow/return pipe runs, then TRV's are sufficient. If the installer has made the sytem into 2 independent zones - old circuit plus new circuit, then a new control system would be required.

The architect was covering all eventualities, IMO, to cater for the new build being on a separate zone.

 

[sv969]

Makes sence. Thanks for your help.

 

[sv969]

1 final question....

All the new rooms in the extension lead off from the house's main hall where the existing thermostat/controller is situated.

As far as I'm aware, you cant have a radiator trv and a room thermostat/controller in the same room, so, in my mind, there is nowhere to I could place a new zone controller.

If this is so, does it mean that the exisiting heating system can just be extended without any zoning at all?

Thanks

 

[dextrous]

If you have a controller/stat in a room for the new zone, then you don't put a TRV on that rad.

Now that we know a bit more what we're dealing with, my guess would be that the architect was looking at the existing CH system being zone 1, and the extention as zone 2. Each zone is isolated by it's own 2-port valve.

Control can be done using a multizone time controller (something like a Honeywell 9500C), plus 2 new roomstats - one as it currently exists in Zone 1 and one in the living area of the new Zone 2. As said above, rads within the same rooms as the stats don't have TRV's, but all other rooms do.

Some of this setup may be possible using wireless controllers, which may save on redecoration.

 

[sv969]

Yes I see. Thanks...

I'm just looking at the Honeywell CM Zone setup to see if it fit my needs. From what I understand, it creates wirelessly controlled zones by independently controlling the radiator valve, therefore, doing away with the need for trv's in the main system....though I might be wrong! More reading needed.

 

[dextrous]

You will need TRV's on all rads in all rooms where there isn't a room stat - and you'll only need two of these if you have two zones. I am not familiar with the CM item you refer to but will look into it. Hopefully some more knowledgable will chip in soon.