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Grundfos Alpha 3 Pump Settings for Hydronic Balancing

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hallra

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Hi Forum,

I am attempting to manually balance the radiators in my house, to get an average of 11c drop between Flow and Return on each radiator.

I have set the boiler temprature to 65c.

With the Grundfos Alpha 3, it has several control modes, with each mode needing a value set:

Constant Pressure requires a setpoint in metres.
Proportional Pressure requires a setpoint in metres.
Constant Curve requires a setpoint percentage.
Radiator Mode (Auto Adapt)

- Most manual balancing advice out there, states to start with a run speed of II, then change it if the 11c balancing can't be achieved.

With this option not avaiable, would running a constant curve (which I believe is a constant speed) at say 65%, be the way to go or I should be using something else?


All advice would be much appreciated


Thanks
 
hallra said:
Hi Forum,

I am attempting to manually balance the radiators in my house, to get an average of 11c drop between Flow and Return on each radiator.

I have set the boiler temprature to 65c.

With the Grundfos Alpha 3, it has several control modes, with each mode needing a value set:

Constant Pressure requires a setpoint in metres.
Proportional Pressure requires a setpoint in metres.
Constant Curve requires a setpoint percentage.
Radiator Mode (Auto Adapt)

- Most manual balancing advice out there, states to start with a run speed of II, then change it if the 11c balancing can't be achieved.

With this option not avaiable, would running a constant curve (which I believe is a constant speed) at say 65%, be the way to go or I should be using something else?


All advice would be much appreciated


Thanks
Click to expand...

Which model (head) have you got is it the 4M or the 6M or the 8M, you should see 40 or 60 or 80 at the end of the pump label, something like 25-40 etc. Also what is the boiler output (condensing or non condensing?) and number of rads and have you got zoning or TRVs or whatever on your system?.
 
Hi John,

It’s the Alpha 3 Model B 15-50/60, so 6M.

The boiler is a Glowworm Ultracon 24HXI, the manual says condensing boiler on its cover.

The piping is a S Plan layout.

There are 8 steel panel Rads and two towel rails.

The house is microbore throughout.

It is piped for one zone, 8 Rads have Smart TRVs and 2 have manual TRVS.


Let me know if other information is needed?


Regards

Richard
 
Last edited:
hallra said:
Hi John,

It’s the Alpha 3 Model B 15-50/60, so 6M.

The boiler is a Glowworm Ultracon 24HXI, the manual says condensing boiler on its cover.

The piping is a S Plan layout.

There are 8 steel panel Rads and two towel rails.

The house is microbore throughout.

It is piped for one zone, 8 Rads have Smart TRVs and 2 have manual TRVS.


Let me know if other information is needed?


Regards

Richard
Click to expand...
 

OK, thanks. As you have a condensing boiler set to 65C then I would suggest aiming for a rad deltaT of 15 to 20C to get the maximum condensing effect as long as it doesn't affect your rad outputs too much.
I would suggest a first setting of PP3 which is 2.25 to 4.3M head, then read off and write down the power consumption, then change to CP2 which is 3.2M constant pressure and again read off and write down the power consumption, then change to Auto Adapt (if available on that pump) and again read off and write down the power consumption. Try and do the initial readings with all rads and hot water cylinder calling for full heat, if your system is up and running just now I would still do the above. I have a somewhat similar set up to your one with a different pump (no auto adapt) and on a PP setting of 2.0 to 4.0M the power consumption varies between 20/22W and 12/14W when the TRV's are throttled/throttling down, the (20 kw, non condensing) boiler deltaT is ~ 22/24C.
 
Last edited:
Hi John,

thanks for the infomation, however, I'm not sure how to set PP3 and CP2 on the Alhpa 3, as these settings are not available and it's where I get stuck.
- I think PP3/CP2 are settings on Aplha 2.
- No Information in the Alpha 3 manual on how to do it.

For propotional pressure and constant pressure, there is no range, just a single setpoint in 0.1m increments.
- do you know how I can mimic the PP3 & CP2 seetings you suggest?

From what I understand, AutoAdapt automatically adjusts it own PP/CP setpoints, however, when I've used Auto Adapt, the system struggles to heat up the radiators and rooms can't retain heat.

Finally, with doing as you advise, once I have all these readings, how do I best decide what to stick with, what to use to get the Delta T close to 15/20c.

So for all the questions, but the manual is hopeless and Grundfos support more so.
 
hallra said:
Hi John,

thanks for the infomation, however, I'm not sure how to set PP3 and CP2 on the Alhpa 3, as these settings are not available and it's where I get stuck.
- I think PP3/CP2 are settings on Aplha 2.
- No Information in the Alpha 3 manual on how to do it.

For propotional pressure and constant pressure, there is no range, just a single setpoint in 0.1m increments.
- do you know how I can mimic the PP3 & CP2 seetings you suggest?

From what I understand, AutoAdapt automatically adjusts it own PP/CP setpoints, however, when I've used Auto Adapt, the system struggles to heat up the radiators and rooms can't retain heat.

Finally, with doing as you advise, once I have all these readings, how do I best decide what to stick with, what to use to get the Delta T close to 15/20c.

So for all the questions, but the manual is hopeless and Grundfos support more so.
Click to expand...

You say "For propotional pressure and constant pressure, there is no range, just a single setpoint in 0.1m increments." can I take it then that you can select proportional pressure (PP control) and incrementally increase it? if so just select it and increase it to 4.0 or a little higher say 4.3.
What setting are you using now? and what is the power consumption??. I thought that the Auto Adapt might be a bit weak alright, can you remember what was its power consumption?.

Can you please post a link to your instruction manual, thanks.

Edit: Is this the pump & manual (attached).?
Sorry had wrong file...is this it, I think so.

Edit again: reading this file it would appear that you need the Grundfos GO App??? and the pump comes in the default mode of Auto Adapt, have you got this App? if not what, if any, settings can you change.?

You might be able to download the app and configure it from your laptop....have a read of this.
A New Grundfos Pump Range is Circulating - Plumbase Blog

 

Attachments

  • Grundfos Alpha 3 Model B.pdf
    6.5 MB · Views: 34
Last edited:
Hi John,

Yes, I have the Grundfos Go Remote app on the phone, it configured/controls the Alpha 3 pump.

It uses Bluetooth to talk to the pump.

It allows the control mode, operating mode & setppoint to be set

7E9272AE-30CE-43F8-8478-55E5043B2249.png
 
The app can also produce this report. (attached)

I can create one for Constant pressure and Auto Adapt, if the contents are useful?
 

Attachments

  • constant pressure 15th Feb 2019 time 2110.pdf
    500 KB · Views: 9
hallra said:
The app can also produce this report. (attached)

I can create one for Constant pressure and Auto Adapt, if the contents are useful?
Click to expand...

Thanks for that, now, the reading of 0.4 M3/hr (6.7 LPM) @ 3M on CP, my system has almost double that flow rate @ 3M ie ~ 12 LPM so it would appear that you have a lot of resistance to flow, possibly in part due to the micro bore piping. The only way, without major piping surgery, to get the flow rate up is to increase the pump head, but because head is proportional the square of the flow then if you require say a minimum of 12 LPM with everything opened up you would need a pump head of, (12.0/6.7)^2, or 9.6M,
I would set the pump to its maximum possible head in CP mode now and see what the resultant flow rate is and the power consumption.
I think you can set the max flow on that app as well in the different modes so ensure that it is not < 1.5 M3/hr.
 
Now I have very noisy radiator valves. :)

Are you saying that that pipework is badly undersized?
- This is a new build and if there is a problem with pipework, it should be covered by LABC warranty... you thoughts will be very useful...

That aside, should I be opening up the lockshields tomorrow to see if I can get a delta T of 15-20
 
hallra said:
Now I have very noisy radiator valves. :)

Are you saying that that pipework is badly undersized?
- This is a new build and if there is a problem with pipework, it should be covered by LABC warranty... you thoughts will be very useful...

That aside, should I be opening up the lockshields tomorrow to see if I can get a delta T of 15-20
Click to expand...

Oh yes, I should have ephpasised that from the start, open up everything on every rad fully, locks shields included and start from scratch again, if the main supply & return headers are even 3/4 ins then as long as the rads arn,t daisy chained in micro bore then the head losses should,nt be excessively high, when you start again with everything opened up you can then see if there is something wrong.

What setting were you on before you started throttling the lock shields?

The ~ way that I calculate the delta T required is : in your case, 8 rads @ 2 kw each = 16 kw, deltaT required 20C, minimum total flow rate required is then, 16*860/20/60, or 11.5 LPM or 15.3 LPM at a deltaT of 15C.
 
When I started to balance manually today, I had it on constant curve with a setppoint of 65%, it wasn’t working well....

Yesterday, I had made use of the Grundfos hydronic balancing application, GO Balance, but once the software guided balancing was complete and pump switched into Auto Adapt mode, the radiators weren’t heating correctly... and one was stone cold...

The Go Balance Application It requires a series of user inputs, which some I had to guesstimate and some it would refuse to accept as it would predict that the required heat output for a given room was not achievable... - So I ended up lowering figures until it would accept them... which then probably as a consequence messed up the balancing...
 
hallra said:
When I started to balance manually today, I had it on constant curve with a setppoint of 65%, it wasn’t working well..

Yesterday, I had made use of the Grundfos hydronic balancing application, GO Balance, but once the software guided balancing was complete and pump switched into Auto Adapt mode, the radiators weren’t heating correctly... and one was stone cold...

The Go Balance Application It requires a series of user inputs, which some I had to guesstimate and some it would refuse to accept as it would predict that the required heat output for a given room was not achievable... - So I ended up lowering figures until it would accept them... which then probably as a consequence messed up the balancing...
Click to expand...

Ok, well to recap, before any balancing is done I think you have to be absolutely certain that your system has been plumbed properly. The pump head and flow rate will tell a lot as it has done so except that the software is fooling everyone then it would appear that your system has a very high resistance.
The cylinder coil itself, even IF all the rads are shut off should flow ~ 6 to 8 LPm at a 3M head as it is basically a 3/4 ins by pass.
 
hallra said:
I believe everythging is open, all TRVs are.

Bypass is closed.

The hot water is off.
Click to expand...

Should have seen that earlier, if you care to do one more test open the coil MV, c/o to CP setting 3M and see what the result is as there is hardly any restrictions in the coil.
hallra said:
I believe everythging is open, all TRVs are.

Bypass is closed.

The hot water is off.
Click to expand...
 
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