controlling large domestic system with Honeywell HR80 TRV

[JonCa]

These wireless TRV’s are used on a number of Honeywell systems such as Hometronic. The System controller tells the HR80 what temp at what time and the HR80 manages the demand to the boiler controller accordingly.

I’m looking to control a large domestic system that covers 8 ground floor rooms and 7 first floor rooms plus hall/landing/stairs. Two rooms have a number of radiators in them so it may be best for each of these rooms to be setup as conventional zones with two port valve and prog t/stat each. Then everything else could be HR80.

Any opinions please. Which systems have you used and what are your impressions/experiences.

Thanks Jon

 

[ALEC1]

My experience of these things has not been good because the pump ends up dead heating quite alot and the flow throught the boiler very reduced.

ALthough there was a by pass this did not prevent pump failure.

I would advise that you install a low loss header between the two circuits...

 

[JonCa]

Thanks, and could you expand on this phrase please

dead heating

 

[ALEC1]

sorry dead heading...

 

[JonCa]

Alec1, surely any TRV could cause that as they could all shut down once up to temp especially in a small installation.

 

[JonCa]

Bump

 

[Dan Robinson]

Are you re-piping the the system or retrofitting?

 

[ALEC1]

yes TRVs can also be problematic... modern condensing boilers do have minimum flow rates.

Much better to vary the temperature of the whole system as opposed to the flow through it, that way you always satisfy the boiler's minimum flow rate

 

[JonCa]

Are you re-piping the the system or retrofitting?

Mainly retrofitting,
- will have to do a little re-piping to create the two new zones but that's a simple cut here and join there plus about four meters of pipe and
- there are a two locations where pipe sizes are to small
- 1 x 15mm, before complex joint (1 in 3 out). ought to be 22mm through joint and
- 1x 22mm, for some reason 28mm from boiler drops to three meters of 22mm as soon as it goes underfloor then splits to 2 x 22mm. ought to be 28mm or possibly two x 22 as could use to feed new zones.

So some work on ground floor, nothing upstairs or on H/W cct. but in the scheme of things not much