22mm or 15mm cold water feed to Megaflo?

[smarriott]

Hi

I have had three heating engineers around to quote for a new boiler and megaflo system.

Two have stated I need to put a 22mm feed to the megaflo, one has stated 15mm will be OK as the pressure is fine, but 22mm would be the ideal.

Can anyone comment/advise as to whether I need to upgrade to 22mm?

Thanks

 

[BingoBongo]

must be 22 no ifs or buts or 15mm speedfit

 

[corgiman]

Manufacturers say 22mm and 22mm it must be if you want them to honour the guarantee

 

[smarriott]

Struth, you guys are quick off the mark.

22mm it is then

Thanks

 

[heatingman]

Megaflow will still honour the g/tee if the unit is on an undersized water main, ie 15mm, they have a disclaimer in the install instructions regarding performance. You might have an acceptable flow on your existing main and the cost of upgrading might be very high, maybe the guy who said 15mm will work didn't make things clear enough.
I have installed many unvented units on undersized mains (customers choice) and only a couple have gone down the road of extra expense to up-grade the main. One was definitly unimpressed with extra performance when set against cost of works, Thames Water, mini-digger, new drive etc.