balancing underfloor heating

[pdiddy]

Hi all.

I've had a recent extension with underfloor heating manifold (r553fx giagomini manifold) installed consisting of 3 loops in the same zone with a nest thermostat. I've got approximate lengths, pitch, which I have on Giacomimi drawing that was given to the builder.

I'm not convinved the builder has bakanced the system. I have 1 loop which doesn't heat up as well as others and has a colder patch which also makes me think it has air in it. I also lose pressure so i think there may be air in the system,

I would appreciate some advice on the below first of all to ascertain optimal performance/energy and then work my way back sorting air locks/pressure etc:

My boiler is set at 55degrees flow
he flow temperature gauge is about 42 (the drawing says this should be 55). The thermostat mixing valve is set to about 3.
the return temp gauge is about 28 (the drawing says this should be 45 with delta t of 10)
the pressure gauge shows 1.5 (black line) and 4 bar (red line)
loop 1 appears to suggest 0.5 l/min. (the drawing says this should be 0.9 l/min)
loop 2 appears to suggest 2 l/min (the drawing says this should be 1.10 l/min)
loop 3 appears to suggest 0.5 l/min (the drawing says this should be 1.2 l/min)

the valves for all 3 loops are turned fully anticlockwise (the drawing says alve sets should be set to 0.25)

if anything i've written doesn't make sense please let me know as I'm not a plumber! thanks.

 

 

[Fly100]

Salus auto balancing actuators are very good and remove the flow rate lottery. Personally I found setting them on day 1 was no good for any other days. Fitted the Salus ones, significantly better and slightly faster warm up times.

[Olf]

6 hours ago, pdiddy said:

he flow temperature gauge is about 42 (the drawing says this should be 55). The thermostat mixing valve is set to about 3

What is the floor finish? 42 is already high for some materials. 

But in principle, until you can't get enough heat of the floor, the lower-the better, so 42 is fine. 

What is the heat source?

 

6 hours ago, pdiddy said:

the return temp gauge is about 28 (the drawing says this should be 45 with delta t of 10)

Good news, the floor extracts a lot of heat from water, maybe even too much

 

6 hours ago, pdiddy said:

the pressure gauge shows 1.5 (black line) and 4 bar (red line)

As long as it stays at 1.5 Bar long term (it will fluctuate with temperature changes) it is fine. Red line if indicated by a hand is probably adjustable, 4 is fine.

 

6 hours ago, pdiddy said:

loop 1 appears to suggest 0.5 l/min. (the drawing says this should be 0.9 l/min)
loop 2 appears to suggest 2 l/min (the drawing says this should be 1.10 l/min)
loop 3 appears to suggest 0.5 l/min (the drawing says this should be 1.2 l/min)

the valves for all 3 loops are turned fully anticlockwise (the drawing says alve sets should be set to 0.25)

Are the loops of the same length and shape? Loop 2 seems to be using 2/3 of the total flow, possibly saturating the pump in the process. Turn the valve on that loop slowly until you get about 1l/min and see if the other loops pick up. You may struggle to adjust precisely, but at least you'll get an idea of what is happening in the circuit with loop 2 slowed down.

5 hours ago, Fly100 said:

Salus auto balancing actuators are very good and remove the flow rate lotter

I'm also finding it impossible to adjust flows with manual valves, Salus kit waiting for installation.

[pdiddy]

Thanks old and fly

 

Responses to comments below

 

Pressure does increase above 1.5.  I've noticed it at 2 today. Not sure if this a problem

 

The floor is tiled porcelain

 

Heat source is a worcester bosh greenstar set at 55 degrees flow

 

The loops length are all approx same around 70m. Not sure of exact lengths installed.  Maybe 10m difference possibly.  They are laid concentric I believe.

 

I've had a go at adjusting the loops and wow...its sensitive and at such low flow rates it's hard to know what I'm setting it to. Maybe I need salus too...how easy is it to fit these bad boys?  Does system need draining down?

 

Thanks again.

 

 

[Fly100]

Salus actuators, clip sensor on the flow and return of each circuit and fit the actuator, wire into wiring center. let them calibrate. job done. 

[john0wingnut]

44 minutes ago, Fly100 said:

Salus actuators, clip sensor on the flow and return of each circuit and fit the actuator, wire into wiring center. let them calibrate. job done. 

How have you found these?

 

I have just fitted some, to one of my manifolds to test them out, but for some reason, they are behaving in an odd way, or thats how I have perceived it.

 

My lounge and Master Bed zones have two loops each, and even post calibration, the valves open at full flow and just sit there. They don't appear to throttle the flow back at all, room reaches temp, zone shuts down. I understand they try and maintain a delta of 7 degrees between flow and return, but looking at my manifolds, this never happens - flow usually sits about 3-4 degrees higher than return, but i do appreciate this is not necessarily what is being detected by the pipe sensors.

 

My ensuite is a short single loop circuit, and the Salus ABA on that one does indeed work as intended. Opens full flow then throttles back to about 1l/s, the 7 degree variance is reached

 

Has certainly confused me somewhat - am I have tried re-calibrating numerous times, but no change.

[Triassic]

Have you manually balanced the flow meters on each outlet from the manifold?

[john0wingnut]

5 minutes ago, Triassic said:

Have you manually balanced the flow meters on each outlet from the manifold?

They were manually balanced by the installer several years back, but as one room wasnt getting flow on one loop, no matter how much messing about was done, I have now gone the Salus ABA route, which requires the flow meters to be fully opened for Salus ABA to work

[Triassic]

1 minute ago, john0wingnut said:

They were manually balanced by the installer several years back, but as one room wasnt getting flow on one loop, no matter how much messing about was done, I have now gone the Salus ABA route, which requires the flow meters to be fully opened for Salus ABA to work

Is that loop working now? Airlock or blocked?

[john0wingnut]

Just now, Triassic said:

Is that loop working now? Airlock or blocked?

Working now, but with the issue as per above.

@Nickfromwalesadvised me previously it was potentially "bypassing" causing my issue, but with the Salus ABA, they are getting equal flow now, but just dont seem to throttle back!

[Fly100]

1 hour ago, john0wingnut said:

How have you found these?

 

I have just fitted some, to one of my manifolds to test them out, but for some reason, they are behaving in an odd way, or thats how I have perceived it.

 

My lounge and Master Bed zones have two loops each, and even post calibration, the valves open at full flow and just sit there. They don't appear to throttle the flow back at all, room reaches temp, zone shuts down. I understand they try and maintain a delta of 7 degrees between flow and return, but looking at my manifolds, this never happens - flow usually sits about 3-4 degrees higher than return, but i do appreciate this is not necessarily what is being detected by the pipe sensors.

 

My ensuite is a short single loop circuit, and the Salus ABA on that one does indeed work as intended. Opens full flow then throttles back to about 1l/s, the 7 degree variance is reached

 

Has certainly confused me somewhat - am I have tried re-calibrating numerous times, but no change.

 

Are they screwed down tight. The pins on the manifold move about 4-5mm and a 1/4 turn short on that course thread is a good mm or more. im sure ive read if the flow temp is low it goes for a 10c differential. Also are the sensors far down the pipes ?

Edited December 7, 2021 by Fly100

[john0wingnut]

26 minutes ago, Fly100 said:

 

Are they screwed down tight. The pins on the manifold move about 4-5mm and a 1/4 turn short on that course thread is a good mm or more. im sure ive read if the flow temp is low it goes for a 10c differential. Also are the sensors far down the pipes ?

They are screwed on slightly over hand tight, - saw this advice in another thread

 

Info re function:

To correctly balance the flow of heated water through the UFH circuit the flow rate needs to be regulated: too much flow will lower the ∆T below 7°C and the circuit will heat up too fast, too little flow will increase the ∆T above 7°C and the circuit will heat up too slowly. The THB230 auto balancing actuator is the answer for getting effective control of your UFH circuit. The THB230 will constantly measure the ∆T via the two temperature sensors and adjust the valve position by closing or opening its slightly. All to maintain constant 7°C temperature differential (between the emitter flow and return pipes) and make your UFH circuit really effective - economy and convenient.

 

Pipe sensors are 10cm down from manifold, facing forward as per the Salus manual

Edited December 7, 2021 by john0wingnut
found info on how ABA work

[Nickfromwales]

Have the loops all been fully purged with cold mains water at full wallop to blast them clear of all trapped air? If this has not been done properly you’ll never get proper flow. 
Running the manifold with the automatic air vent as a means to remove trapped air is no good whatsoever as the flow rates are extremely low and absolutely will not get the air locks out.

Edited March 19 by Nickfromwales
Edited a typo I made 3 years ago. That’s dedication for you lol.