Choosing a Greenstar 30 HE plus combi

[gsportgeorge]

Should be getting a boiler fitted in the next few weeks so it is time to decide on one.

Seems like the Greenstar 30 HE plus combi is the one we will go for.

Any horror stories, special problems/issues or precautions...

Information:-

Very soft water area.

Flue should be straight forward (horizontal straight through stone (rubble fill) wall miles from any windows.

Totally new system (house has never had CH before)

Just 3 or 4 rads initially (professionally fitted, ground floor only so easy access from cellars) total load 10kw (rest will go in soon after when we can afford them) I want to mount and plumb the upstairs myself to save cash and minimise damage. I realise it wont perform very efficiently until we get the rest of the rads and expansion vessle fitted)...

 

[COG]

The eficiancy should be ok as you can range rate the heating,if you only have a 10kw load then you can set the ch output to 33%. Why do yo mention another expansion vess when the one fitted to the boiler is more than capable ?. Make sure that it has a decent gas supply pipe with as few bends as poss ,but your fitter should no that.

 

[gsportgeorge]

... Why do yo mention another expansion vess when the one fitted to the boiler is more than capable ?..

I cant find the capacity of the built in expansion tank now but I seem to remember that it is limited to a total system volume of about 100-125litres ?

We anticipate having a total system volume of about 140litres eventually...


Gas supply pipe will be fairly long (about 12-15m) and will inevitably have at least 3 90degree bends in it.... should we push for a 28mm gas pipe then reduce it down at the appliance?

 

[ChrisR]

I doubt you'll use that volume for 10kW of convector radiators, have you done the sums based on those?

I would expect your corgi to use 28mm, but I doubt he'd appreciate being told what it should be!

 

[gsportgeorge]

^^^ 10kW is the initial load with just the ground floor plumbed...

The extra expansion tank will be fitted when we do the first floor and loft rads.. which will bring the load up to about 24kW and the volume up to 140litres odd...

 

[COG]

When you finish the system you can go into the pump mapping ,not just the pump speed but resistance behind it if you set it at perm high to start with to balance the sytem then take it down if required.