Delta T target

[athlonoc]

My UFH system has 7 flow and returns and I'm trying to balance the system.

I've bought two Testo 115I thermometers for flow and return measurements.

It appears well documented to try and get a Delta T of 5 degrees and I can mange this on the 3 smaller loops.

 

The two larger loops being my kitchen and lounge both have two flow and returns circuits. Unfortunately I have no idea of their length. I can't get my flow valves to allow more than 2l/m as I believe I would need to do this, to achieve a lower Delta T of 5. Its currently between 7 and 8

The flow meters which are now fully unscrewed tight, will not allow a drop greater than 2l/m

 

Is it possible that the circuit pump for the UFH needs to be increased? Will this help  

[JohnMo]

No need to obsessive about this - are rooms warm enough or hot cold?

 

But generally the best way is based on room temperature not flow rate. An ideal flow rate and dT doesn't matter if you room never gets hot.

 

Run pump at full speed, set flow rates, then reduce speed until you see flow rates start to drop.

 

[SimonD]

1 hour ago, athlonoc said:

to achieve a lower Delta T of 5. Its currently between 7 and 8

The flow meters which are now fully unscrewed tight, will not allow a drop greater than 2l/m

 

In most systems I work on and commissioning, I find anything between 5 -9 is okay.

 

Start on minimum pump speed and only if necessary up the speed.

 

Don't worry about playing around with it. You can up the pump speed and see what happens and then leave it for a few days to see how it performs. And then if necessary reduce pump speed back to where you are now.

[athlonoc]

4 hours ago, JohnMo said:

No need to obsessive about this - are rooms warm enough or hot cold?

 

But generally the best way is based on room temperature not flow rate. An ideal flow rate and dT doesn't matter if you room never gets hot.

 

Run pump at full speed, set flow rates, then reduce speed until you see flow rates start to drop.

 

Thank you.

 

Trying not to obsess about this but I noticed the WC was taking ages to get warm. So thought it wouldn't harm to balance the system. 

I guess it will be impossible to get all to sit at DT 5 without spending hours if not days messing around.

Just for knowledge:-

If I did want to balance say the Cloakroom. Should I only have that loop calling for heat? Would the overall Flow and Return of that loop get affected if I allowed the other 6 loops to heat up at the same time as balancing that single loop ( my Cloakroom )?

 

[athlonoc]

2 hours ago, SimonD said:

 

In most systems I work on and commissioning, I find anything between 5 -9 is okay.

 

Start on minimum pump speed and only if necessary up the speed.

 

Don't worry about playing around with it. You can up the pump speed and see what happens and then leave it for a few days to see how it performs. And then if necessary reduce pump speed back to where you are now.

Thank you Simon

[JohnMo]

7 minutes ago, athlonoc said:

Trying not to obsess about this but I noticed the WC was taking ages to get warm

That raises a question - do you not run WC all the time, are you trying to run WC and a schedule at the same time? Or running WC and thermostats?

 

8 minutes ago, athlonoc said:

If I did want to balance say the Cloakroom. Should I only have that loop calling for heat? Would the overall Flow and Return of that loop get affected if I allowed the other 6 loops to heat up at the same time as balancing that single loop ( my Cloakroom

You need every loop on really, otherwise you get a miss balance of flows.

 

 

[athlonoc]

4 minutes ago, JohnMo said:

That raises a question - do you not run WC all the time, are you trying to run WC and a schedule at the same time? Or running WC and thermostats?

 

You need every loop on really, otherwise you get a miss balance of flows.

 

 

The running of just the WC was for balancing purposes. 

I wasn't sure if I should balance one at a time with the other loops off. 

I'm not running a schedule for heating, no.

It was a theory that you have now answered, in that it doesn't need to be done like that. I should have all loops flowing.