Polypipe UFH System Help - very low flow

[Nickos]

Hi Guys,

 

I've got a polypipe UFH system that serves 9 circuits of varying length that currently is barely registering any flow, i can never get it to go above 1L. Pics attached as well as one of the pump operating mode.

 

I've tried:

Flushed the whole system as per the manual and there is no air present in any of the circuits.

Open and closed circuits.

Changed the Auto Flow lpm on the top of the rail beneath the actuator.

 

Any suggestions what to look at next ?

 

I've also tried to draw the system in to assist with any advice although some icons might may be slightly out as it's all i could find.

 

 

[JohnMo]

Basic question first, is the two way valve opening?

 

Is that a pressurised thermal store?

[Nickos]

18 minutes ago, JohnMo said:

Basic question first, is the two way valve opening?

 

Is that a pressurised thermal store?

 

I assume it must be as the floor does get warm, and i can see the mix flow and return temps change. I did hold the manual bit on the end down and saw no change.

 

Yep, it's pressurised although the UFH is fed straight off the boiler.

[PeterW]

1 hour ago, Nickos said:

one of the pump operating mode.

So your Red/1-34 lights on your pump assuming it’s in programme mode not fault mode, and it is in PMW mode. That is external control mode not internal so has someone been pushing buttons..? If it’s left like that it will run at  100% flow rate but would check this.

 

Probably need to get it into internal mode (assuming there is no PMW controller, just a relay) and set it to the correct curve

 

start with the quick guide here 

 

https://cdn1.omnie.co.uk/wp-content/uploads/20180601120219/GRUNFOSS-UPM3-FLEX-AS.pdf

[Nickos]

18 minutes ago, PeterW said:

So your Red/1-34 lights on your pump assuming it’s in programme mode not fault mode, and it is in PMW mode. That is external control mode not internal so has someone been pushing buttons..? If it’s left like that it will run at  100% flow rate but would check this.

 

Probably need to get it into internal mode (assuming there is no PMW controller, just a relay) and set it to the correct curve

 

start with the quick guide here 

 

https://cdn1.omnie.co.uk/wp-content/uploads/20180601120219/GRUNFOSS-UPM3-FLEX-AS.pdf

 

I pushed the button to view the mode. I can see when the UFH is running that it does change between 25-50% (1 green, 2 yellow) and 50-75% (1 green, 3 yellow) performance view operation status. I've never seen it reach 100.

Edited January 12, 2023 by Nickos

[PeterW]

Ok so you can force it to constant if you read the manual

[Nickos]

55 minutes ago, PeterW said:

Ok so you can force it to constant if you read the manual

 

I couldn't see any reference to switching it to constant although i did change the mode to PWM 7m which increased it a little but still not over 1Ltr on the single zone (2 circuits) i have calling for heat.

[Nickos]

Do i perhaps need an extra pump between the boiler and ufh manifold ?

[JohnMo]

 

2 hours ago, Nickos said:

, it's pressurised although the UFH is fed straight off the boiler.

So your drawing is wrong.

 

Have you tried to adjust a flow meter?

 

Perhaps they are short runs under the floor and the loops are set to a flow rate of around 1?  You state the floor is warm, so is there an issue?  If the floors warm, turn your flow to min speed, (1 light) and job done.

[Nickos]

5 minutes ago, JohnMo said:

 

So your drawing is wrong.

 

Have you tried to adjust a flow meter?

 

Perhaps they are short runs under the floor and the loops are set to a flow rate of around 1?  You state the floor is warm, so is there an issue?  If the floors warm, turn your flow to min speed, (1 light) and job done.

Not wrong, just a little poor as the pipes go behind the tank.

 

I've adjusted them all, one at a time, variations and nothing. Can never get anything above 1ltr per minute, whether it's open/closed to whether top manifold valve is set to 1 lpm or 30 lpm.

 

Loop lengths are:

 

Room	Circuits	Length	Width	Room Sq Mtrs Sub	Room Totals	Total Meters Per Circuit	Flow Rate (m/40)	Manifold Setting
Lounge	2	5.38	3.55	19.10	19.10	98.98	2.47	14
				0.00
Kitchen	2	3.84	3.28	12.60	23.03	99.94	2.50	14
		3.56	2.93	10.43
Hall	2	3.89	0.85	3.31	12.83	66.45	1.66	10
		4.27	2.23	9.52
Bedroom	2	3.78	3.06	11.57	11.57	70.70	1.77	10
				0.00
Bathroom	1	1.78	1.7	3.03	3.03	43.22	1.08	6

Edited January 12, 2023 by Nickos

[JohnMo]

You are set to auto flow.  So this will basically manage the flow through the system and I think how much energy is going into the floor.  If your flow temp is high the flow rate doesn't need to as high to get the same energy transfer. 

 

Reduce the mixer flow temp, your flow rates should increase, but it may take a while to change.

 

Worth a try. 

 

If you are connected direct to the boiler, can you control CH flow temp independent of cylinder flow temp,?  If you can you could just reduce boiler temp to get more efficient operation from the boiler.

 

 

[Nickos]

7 minutes ago, JohnMo said:

You are set to auto flow.  So this will basically manage the flow through the system and I think how much energy is going into the floor.  If your flow temp is high the flow rate doesn't need to as high to get the same energy transfer. 

 

Reduce the mixer flow temp, your flow rates should increase, but it may take a while to change.

 

Worth a try. 

 

If you are connected direct to the boiler, can you control CH flow temp independent of cylinder flow temp,?  If you can you could just reduce boiler temp to get more efficient operation from the boiler.

 

 

That was my initial thought but spoke with polypipe directly and they advised even on auto flow, the rates should show correctly. I.e. the kitchen flow meter should read 2.5. Its a total mind bender but will try changing the mixer down to 40 next. Boiler flow currently at 60c. Not sure about how water temp, I'll have to do some reading but it seems scorching.

 

Didn't bother me tuning wise when gas was 2.5p kwh but at 4+ times that it's hurting the pocket so I want it optimal as can be.

Edited January 12, 2023 by Nickos

[JohnMo]

So every day a learning day.  Did you do this?

 

https://www.google.co.uk/search?q=polypipe+Auto+Flow+setup&biw=384&bih=660&sxsrf=AJOqlzVvMtO2zjAo1bAcKHFHi65vmKudxg%3A1673544670996&ei=3kPAY8azPNCigQb29LLwDg&oq=polypipe+Auto+Flow+setup&gs_lcp=ChNtb2JpbGUtZ3dzLXdpei1zZXJwEAMyBQghEKABMgUIIRCgAToKCAAQRxDWBBCwAzoECCMQJzoECCEQFUoECEEYAFCLDVjuJGClKGgBcAB4AIABpQKIAdwLkgEFMC42LjKYAQCgAQHIAQjAAQE&sclient=mobile-gws-wiz-serp#

[JohnMo]

Just checked the link it's the first video that comes up.

[Nickos]

3 minutes ago, JohnMo said:

Just checked the link it's the first video that comes up.

Yeah, went through all their videos, even flushed the system twice just to be sure. Did call a couple of plumbers to take a look but most must be snowed under or just don't want to know.

[PeterW]

3 hours ago, Nickos said:

Do i perhaps need an extra pump between the boiler and ufh manifold ?

Yep … although hasn’t the Vaillant got one built in ..? That should be more than man enough to push heat into the manifold. 

[Nickos]

55 minutes ago, PeterW said:

Yep … although hasn’t the Vaillant got one built in ..? That should be more than man enough to push heat into the manifold. 

Yep, checked that too. I'm hoping it's something simple but it's a weird one! Thanks for the help so far.

[JohnMo]

So when you commissioned the flow rates, did you get full flow at any point?

 

As the procedure says to start with only one loop open, you should have got the full flow at some points during commissioning?  If you tried to get all the flow rates at one go, that maybe why you are get a low flow on all loops.

[Nickos]

39 minutes ago, JohnMo said:

So when you commissioned the flow rates, did you get full flow at any point?

 

As the procedure says to start with only one loop open, you should have got the full flow at some points during commissioning?  If you tried to get all the flow rates at one go, that maybe why you are get a low flow on all loops.

I can't get full flow on any circuit, even with all others closed other than that 1. The most i can get is around the 1 lpm mark.

 

It was installed and commissioned a few years back but i believe the installer who did it wasn't brilliant.

 

When i flushed and filled it a circuit at a time recently, i did see the flow meters drop as low as 4 lpm so i know they are not stuck.

[JohnMo]

Have you revisited the commissioning procedure and started from scratch.  Basically close everything set all the flow adjusters to zero and the flow setters under the actuators to zero.  Then bring one loop on at a time?

[Conor]

Basic question... But is the pump facing the right direction? I.e. pumping the same direction the boiler pump is? If it's the opposite way round that would account for the abismal flow rates. Same for the valve. Reason I'm asking is that you'd normally have the flow on the top rail, and return on the bottom rail.

[Nickos]

4 minutes ago, Conor said:

Basic question... But is the pump facing the right direction? I.e. pumping the same direction the boiler pump is? If it's the opposite way round that would account for the abismal flow rates. Same for the valve. Reason I'm asking is that you'd normally have the flow on the top rail, and return on the bottom rail.

 

Yep, arrow on the side is shows downward so it's pumping the hot flow. I can also see the flow temp is 45 and it's coming back at 37c ish on the return. 2PV also correct direction.