Baxi Main 30 HE or Greenstar 28i Junior?

[MikeT]

I have a 3 bed detached with 30yr old CH/HW system and have just got a price from a local Corgi plumber for a complete new system.

8 rads, 4 with trv's, dual prog timer/roomstat, new gas supply from garage to porch where I want the boiler and the quote price is £2800 with a Baxi Main 30 HE or £3000 with a Greenstar 28i Junior. This includes removal of all old pipework, rads, tanks etc.

My Question is which boiler should I go for? No baths taken in this house, just showers ;)

The Baxi spec seems to show 2 heat exchangers (1 caste iron the other alloy), the 28i only one? Hot water throughput on the baxi is more 12.1 ltr/min against 11.4 ltr/min Baxi states independent control of hot water /heating temp, dont know on 28i Baxi is 11.9 to 31kw output, Junior is 7.2 to 28kw

Any installers help point me in the right direction please

[Ed Sirett]

Try the BoilerChoice FAQ below for starters.

I'd be interested to know how it is that you have 4 radiators which don't need TRVs. i.e. Non bedrooms, not less frequently used rooms, not subject to large solar gains, not subject to other sources of heat....

[John Stumbles]

I'd avoid the Baxi which sounds like an ancient cast-iron design with a secondary heat exchanger bolted on, and go for the Worcester Bosch. They do do combis with better hot water output but I wonder if a combi is right fro a 3-bed house (how many bathrooms and showers do you have?)

For a fuller discussion of these matters see Ed Sirett's "Choosing a Boiler FAQ"

[MikeT]

The trv's were all for bedrooms and bathroom rads, downstairs is really one big long room 13x36ft. First 24ft is a lounge where the thermostat was going and the rest is the dining area. The dining area does have a large amount of glass (almost 2 walls worth) but faces north and doesnt have great solar gains. All windows are double glazed and walls cavity filled btw.

The other rad was for the hall which on reflection should I suppose have a trv.

Are you thinking the hall should have the stat and the rest of the down rads have trv's then?

I did already read all the faq listed but am still unsure what I should be doing, I really want to do away with the top up tanks and airing cupboard/hot water tank to make way for a maybe loft converted space later. I am also replacing the kitchen units and really would like the old floor standing potterton caste iron boiler out of the way along with its pipework and controls, thats why the boiler in the front porch.

Thanks.

[MikeT]

know. Thats after reading the faq!

2 adults and 2 kids in the house which is shortly to have no bath at all in exchange for a shower cubical.

Thanks.

[John Rumm]

Depends on which two you are counting!

Most combis have two - a primary one heated by the gas flame, and a secondary one for the hot water heated by the primary circuit water.

However when you see one that has two primary heat exchangers (in addition to the HW one) it is usually a clue that it is an old design that has been kludged into operating as a condensing boiler.

[Ed Sirett]

If I were retired or something I could no doubt have produced the illustrated FAQ with lot of colour pictures showing the different features.

The FAQ does make fairly explicit mention of the difference between one-piece and additional secondary exchangers.

[Ed Sirett]

It's relatively little work to add a few TRVs. With such a large room you might find that you need to be able to control whereabouts the heat is added. On the other hand it might alredy be proven to work well, balanced and controllable without TRVs. In any case retrofitting the TRVs is not hugely disruptive.