Underfloor Heating Manifold: How the smeg does it work?

[bonebill]

Have a look at page 2 of this document:

http://www.alderkey.co.uk/literature/Continental UFH Ltd - Construction Guide r200103.pdf

It's a picture of a "Continental" underfloor heating manifold.

But I can't figure out how it is supposed to work.

I thought that underfloor heating gear was supposed to do 2 things:

1. Pump the water around the underfloor heating loop(s).

2. Variably blend hot water flow from the boiler with returned water from the underfloor loop to keep the water in the underfloor loop at the desired temperature.

But I can't figure out how this thing would do that. It seems to have far too many plain Tee joints (three of them) to be able to any kind of proper controlling of any water flow.

 

[ChrisR]

Looks standard - several loops in parallel that's all.

 

[doitall]

looks ok to me as well

 

[bonebill]

Looks standard - several loops in parallel that's all.

Er, yes, that's the dull and obvious part on the right.

I was asking about the bizarre stuff on the left.

Compare it with page 2 of this:

http://www.underfloorheatingsystems.co.uk/pdf/control_pack_instructions.pdf

With the Contintental one, if the floor is cold and it starts running, we will be pumping some uncontrolled mix of (cold) water from the floor and (hot) water through the pump into a Tee junction wherein the amount of water which perchance happened to come out of the underfloor pipes before the pump will now flow back in to the top of the pipes. But therein lies the rub. Although the same amount coming out of the underfloor circuit must go back in, there's nothing to say that this amount needs to be greater than zero. Even if system is cold, and the valve is in position to let in hot water, there's nothing that really forces hot water into the underfloor pipes. I don't see any reason why the system wouldn't just pump water in from the boiler and back out of the return point, completely bypassing the underfloor circuit.

But with the UFHS.co.uk one, if the floor is cold and it starts running we will be pumping undiluted hot water into the floor pipes, no question. There's nowhere else for the water to go.

The Continental one seems very wishy-washy and based on hope and good luck.

The UFHS.co.uk seems to actually be forcing the water to go where we want it to go.

So what gives? Why are there different topologies? Are any of them better or worse?

 

[Stoday]

There are two pumps in the system, one to pump water around the heating pipes, the other to pump water from the boiler to the manifold.

Each flow u/f pipe is connected to the manifold via an electrically operated valve.