Boilers/megaflow - help!! I am getting bamboozled.

[Loueytb3]

Having extension (hopefully) built next month and we need a new boiler. I've had 3 quotes from different plumbers, all of which are totally different. I think part of it is to do with the different specs of the boilers. We are in a 4 bed 2 bath house.

Plumber 1 - quoted for a Vaillant Eco Tec 428 condensing boiler
Plumber 2 - quoted for a Vaillant Eco Tec plus 630 HE condensing boiler
Plumber 3 - quoted for a Worcester 37kw system boiler

Plumber 1 is the cheapest, plumber 3 is the most expensive. Plumbers 2&3 have said we need to power flush but plumber 2 can't do it and nor can his mate as our house is too big. He said it would cost at least £500 to do it properly. Plumber 3 included powerflushing in the quote.

I can't work out what spec boiler we actually need. Does anyone know roughly what spec boiler for that size house?

Also, plumber 3 brought up whether we want to install mega flow at the same time. We currently have a tank in the loft. I don't really understand the advantages of having it and it will cost an additional £3K . If however there are definite benefits to having it then we might well fork out for it now rather than in the future.

Has anyone had a similar system installed who can talk to me about it, or are there any plumbers about?

You have my sympathy! We were given lots of options too making it very difficult to compare.
We had a vaillant system fitted 3 years ago. Worcester Bosch are the best you can buy, but vaillants pretty good too. Can't tell you difference between 1 and 2. We have your second option. We have megaflow cylinder too, but had option of adding later for £900 (two people gave us that price). Will be adding third bathroom to house next year though so decided to get it over and done with.

Controls on vaillants very complicated. Drives us mad every so often. Less so now we're more familiar with it. Not sure what Worcester Bosch ones like.

£900 is a lot cheaper than 3k! If it was only that much we wouldn't hesitate to put it in now. Worcester bosch came out better on Which I think. The other 2 plumbers say they use Vaillant because they come with a 5yr guarantee but so does Worcester at the moment.

Hello all, we have been put up with a similar situation for a mega flow. We shave been told to change our old vintage iron cast radiators as the megaflow wouldn't work properly with it. And have given us a cost of 10000£ which is ridiculous. Can someone suggest a good plumber and an estimated cost for a 4bedroom house 2 bath. For some reason our pipes are outside the walls visible.
Thanks

suggest you start a new thread with your own Q.

You will have to say where you are if you want recommendations.

An unvented cylinder such as a Megaflo can work with iron radiators.