UK Plumber Forum

[Jimmy84]

I'm fitting a valliant eco tec plus 637 system boiler with a low loss header. Question 1, do my primary's in to the the header need to be the highest and lowest points with the secondary's teeing in between or doesn't it matter? Question 2, from the secondary flow they'll be a pump and then to a heating manifold for zoned heating circuits and then another secondary flow to a pump for zoned hot water. Do I need to put a bypass valve after the pumps and before the zone valve to each circuit and link in to the returns back to the header?

Obviously on a heat only boiler an external pump and bypass would be used but didn't no if this applies to a system boiler with an already built in pump and bypass but with additional pumps.

Some help would be much appreciated!

[Croppie]

1. Yes.
2. No, take a moment, have a cuppa, breathe and think about it.