Underfloor heating manifold help!

olafshiel

I have a question thats been bothering me for quite a while now about my underfloor heating. I have a simple manifold with a flow and return. The inlet (hot water) seems to be on the top with big black knobs and the return on the bottom tall narrow knobs with flow metres and I can't work put how to balance the system? What do these valves do exactly? I know they regulate the flow of water somehow, but why two sets? If I want maximum heat should the red needles be all the way up in the return? Should the inlet valves be closed? Anyone got any ideas?

heinbloed

Could you post a photo?

The balancing is usually done to get a similar return temperature from all loops.

olafshiel

Hi,
Thanks for getting back to me. My system is fairly basic. I just can't work out which knob cools a room and which raises the heat or what combination of both I need to use.
many thanks.

Olaf

olafshiel

http://img26.imageshack.us/i/img0402ce.jpg/

This is the url of the image.

heinbloed

I just can't work out which knob cools a room and which raises the heat or what combination of both I need to use.

There is no cooling facility with most installed UF heating system, most are used for heating only.
If you don't know how to balance the system you have to get a real plumber to do this.
To raise the temperature of the floor the boiler's temperature is raised, i.e. the flow temperature is increased, not the flow rate in the circuits (liters per minute passing through the pipe).

olafshiel

Hi, thanks for the reply. Probably a silly question, but what does the top knobs do?
I understand the bottom ones increase or decrease the litres per hour to each circuit, so I can have them completely open or shut. So why have two sets of valves?

Thanks

heinbloed

The upper knobs (flow)are the valves to close or open a circuit. To turn the heating on or off.
Your's seem to be the manual type ones, there are automatic ( room-) thermostat controlled ones as well.
The "bottom ones" are the meters showing how many liters per minute are passing the cuircuit.

I'm not familiar with this type of equipment, so check the following:
At each one of these circuits (either at the flow or at the return) a flow restrictor has to be installed. They are present with your system as well, but I don't know if at the flow or at the return, both can be done.
The setting of these flow restrictor should not be altered after balancing the system.
If done by accident or necessesarily when altering the system it needs re-balancing. Which means that the return temperature from each circuit should be the same, what in turn is achieved by restricting the flow rates until the return temperature is actually all the same from all circuits.

PS
To increase or decrease the output of the UFH and still keeping the heating system efficient the flow temperature has to be changed. Not the amount of liters passing through the UFH circuit.
This is done at the boiler and/or a secondary heat exchanger (if present).

olafshiel

Great, youve been a great help. thanks.

Olaf