SystemLow loss header

[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!

 

[ShaunCorbs]

single boiler or multi boilers?

and flow to the top connection if your using the the vaillant llh the slightly lower top connection is for the boiler the higher one is the system

and any chance of a drawing o what your planning to do

 

[jimmy84]

It's a single boiler install with two hot water cylinders. I haven't actually got a valliant low loss header, but been told to make one. The system has 4 x underfloor heating manifolds and 2 x towel rail circuits.

 

[ShaunCorbs]

Looks fine to me just using two pumps

The only thing I would change is your flow for the cylinders put it above the boiler flow tapping where's your expansion vessel?

Also I wouldn't make a llh there cheap enough under a ton normally

 

[jimmy84]

yeah I meant to draw it with the boiler tapping below the two secondary flows. I've also been told that the boiler tapping has to be the top one then the two secondary's below and vice versa with the returns?

I haven't drawn vessel on here but was going to tee in to the primary return

Would you put bypass valves in after the pumps?

I would personally prefer a pre made llh been been told I have to make one!

 

[ShaunCorbs]

it doesnt matter that much prefer the load higher than the supply

vessel and drain normally on the bottom of the llh

 

[jimmy84]

Cheers for your help

What about bypass valves?

 

[ShaunCorbs]

Cheers for your help

What about bypass valves?

i would normally install them on the end of the manifold but where you have drawn them is fine