Vaillant Ecotec 837 or WB Greenstar 35CDI combi ??

[robert]

Have narrowed my choice of combi wall hung boiler down to the Vaillant EcoTec plus 837 or the WB Greenstar 35CDI.

Any helpful comments to assist with making the final decision ?

Thanks

Robert

House spec is: large 3 beds, 3 floor midterrace, solid rubble walled (ie poor insulation) house. with 1 bathroom and 1 ensuite shower but little simultaneous use. Present boiler Ideal Mexico RS65 okay for CH & HW. Robert

[Ed Sirett]

Frankly this is a bit over the top and you could probably save a few quid by down grading to the the 28-30kW versions.

Also the gas pipe for the 35kW boilers will most likely have to be 28mm, but you'll probably have to upgrade anyway.

Both makes are in the upper-mid market. The Vaillant has a s/s heat exchanger.

[robert]

Agree the CH output is more than I need, but I need a decent HW flowrate and removal of HW cylinder is necessary as part of overall plan.

Gas pipe will have to be replaced anyway its 15mm and about 25metre run at present.

Robert Robert

[John Rumm]

If memory serves, I calculated a max effective length for 22mm pipe feeding a 35kW boiler at only 12m. So as Ed said, "bigger"!

(Personally I would not go for less than 35kW - I find even that is only _just_ good enough)