Purchasing a new combi boiler

[meatpie48]

Right, the boilers gone kaput & now the weather is warming up I've bitten the bullet & decided to replace the old boiler.

I am a mechanical engineer but I deal with installation of chillers, air handlers & boilers over 500kW. I havent got a clue about what is good domestically. Can anyone out there suggest the best 32-45kW combi. I want to oversize as there is going to be expansion.

A biomass at work could go walkabout but my garden is not big enough lol

many thanks

 

[studips]

if you're expanding that much, consider a temporary combi (maybe a second hand one of the ebay with a new flue kit or whatever) and buy a new system boiler + megaflow type system when the expansion happens.

oh, and get the heat loss/usage calcs done to size the boiler properly - overkill is not good with combis, they should work for their keep to be at their most efficient.

 

[Agile]

If you told us the size/heatloss of the property and the number of people living there and the number of baths or showers to be taken together then we would probably advise you to have a cylinder.

No combi can run two showers well!

Tony

 

[kirkgas]

i agree with comments about telling us the proposed hot water load to assit us in helping you choose, but if i was ripping everything out i would go for unvented hot water rather than a combi ( i have just ripped out my isar combi and fitted a Glen Dimplex 30 combi which seems ok, as i cant be bothered with all the hassle/work fitting unvented ) but if you are expanding most combis will fall short

 

[meatpie48]

current total heat loss on a quick calc is around 23kW. Based on current extension plans on both ground & Loft Total Heat loss will 31kW.
This is on a -1 +22 calc.

Once extended we will be looking at HWS feeds to Kitchen(sink), Utility Room (sink), Cloakroom (whb). 1st floor will be shower/bath & whb. Loft will be Shower & whb.

Finished floor to ceiling is 2.6m on both floors.

We have excellent Mains Pressure & Flow.

 

[simond]

You could fit a Vaillant ecoTEC Exclusive 838.

It has a few extra tricks which make it more efficient in use than the standard ecoTEC boiler, it is really a German ecoMAX rebadged, heavier construction, fully modulating pump, bigger HEX.

 

[mickyg]

go for a seperate tank and boiler if you can as others have advised. If you must have a combi and you don't mind paying top dollar, then maybe look at a ATAG Q51C Will need a chunky gas pipe though !