Megaflow installation quote NW London

24 May 2010
Reaction score
United Kingdom

I am a bit lost as to the best way forward. Have a 3 bedroom house with 2 showers and a bath.Initially advised by 2 plumbers that the best system to replace my old boiler is a combi. Now another plumber has advised that due to the size of the property best to go for a mega flow system. Has given the following quotation cost of £3950.00. Just wanted to doublecheck whether the cost is ok and most important if there are any hidden issues that should be raised.
Remove existing boiler, cylinder, tank and redundant pipe work
Supply and install Vaillant 630 System boiler and flue
Supply and install 250 Gledhill sealed cylinder
Supply and install new RF1 roomstat
Supply and install new programmer
Supply and install new cylinder stat
Supply and install 2 x two port motorised valves
Supply and install Magnaclean
Supply and install limefighter
Supply and install Sentinel x 100 and x 300 inhibitor
Supply and install all copper tube and fittings
Run condense back to kitchen sink
Run new 22m water mains subject to where the builder leaves it to sink in kitchen and bathroom
Run gas back to the meter
Carry out full powerflush using chemical cleansing agents
Supply electrician to electrically wire boiler components
Commission gas boiler, test and balance system and supply CP12 Gas Certificate

Total cost
£3950.00 for the installation and an additional £600 for running a 22m pipe from the mains to the property.
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There is absolutely nothing wrong with that price and the man who advised you to fit an unvented cylinder is probably the most experienced and proper plumber

We now have a new generation of plumbers who unfortunately how no clue whot so ever on how to set up conventional heating system and every where you go stick in combi,it laughable some of the situations where i have seen combination boilers fitted,only for us to retrofit a unvented cylinder
Looks about right. I'd suggest a programmable room thermostat though. That's an RF3, or better, the Honeywell version: CM927RF unless they changed it again.

The Gledhill cylinders are particularly thin. Similar price (slightly less) is Plumbcenter's own brand, which is made by Santon, the original Megaflo people.
Slightly more is Vaillant's own cylinder which can be controlled better by the boiler.

Make sure your mains pressure and flow is good enough wherever the unvented is going. You'll need 3bar and 20+ litres/minute.
The new mains pipe is good, as long as the pipe from that to the cylinder is fat enough too.
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Couple of comments from the DIYer.

I hear the Vaillant 630, is about the worse boiler they make.

supply and fit 2 x 2 port valves. Does that include the free one that comes with the cylinder.

Supply and fit cylinder stat. Doesn't that come with the cylinder as well.

I would expect at least a megaflow for that money.

Run new 22m water mains subject to where the builder leaves it to sink in kitchen and bathroom

Not sure about the £600.00 to run a new mains in, assuming the builder is doing the digging. That sound a good price for 30mins work. I would also insist on 32mm blue poly.

What is the mains pressure.

What is wrong with the old cylinder and tanks.

Perhaps you should ask Agile for a quote, first, being as it's in his patch.

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