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Discuss Grundfos Alpha 2 AutoAdapt is slow in the Central Heating Forum area at PlumbersForums.net

M

Marck C

Hi folks be glad of some help with this as its puzzling me.🤔

I have an Alpha 2 15-60-130 pump serving 12 Rads with thermo valves and Hot Water cylinder. The boiler is an Alpha CD18R

Since I had another rad installed downstairs I've noticed the heating pump has been noisier than usual ie running at full bore... annoying when it comes on during the early hours to start the days heating.

The engineer had left it set to III which runs at 45W. It gets the job done but at the cost of the noise. Problem is I dont know what the setting was before. When I put it onto autoadapt the rate drops down to 9W which seems way to slow to get all the rads piping hot. I've found the best compromise is to use the other Proportional Pressure setting on full which provides around 35W and is ok noise wise, but still feels excessive and not very energy efficient

Since it has an autoadapt feature i'd like that to be working for me but it just doesnt seem to give it enough pressure.

So two questions

Anything else I could be checking for?

What power wattage would you expect to see for my system?
 
J

John.g

Hi Marck, you can forget auto adapt as I've never seen anyone saying that it works, most, like you say that it runs at 9W which is completely useless. Strangely enough, the only pump that someone told me was running OK in "Auto" was a Tucson 6M pulling 23W which is quite acceptable.
A pump output of 20/25W is a reasonable power output to satisfy your 12 rads, I also have 12 rads and with my pump (Wilo Yonos Pico) set at a PP setting of 4.1M pulls between 14 and 21W depending on TRVs positions, I can set my pump on PP (or CP) settings incrementally in 0.1M steps, if I set it to your PP3? setting of 4.5M then it will pull around 31/33W, similar to yours. Unfortunately the Alpha2 pump has a big gap between the PP settings so if you were to set yours to PP2 which is 3.0M then you may find that is too low, you can try it (with all rads "full on", if its below ~ 14W then a bit weak IMO to satisfy all the rads, unfortunately, the CP settings are the same as the PP settings and the fixed speed settings are again either too low or too high.
But, its only a button press, would suggest trying PP2, CP2 and constant curve 2 (fixed speed 2) and jot down the pump power for each, you can then make a decision based on what I suggested above and if you don't mind, post back your results.

One other thing I notice is that your pump was pulling 45W at fixed speed 3 whereas according to the Alpha2 pump curves, the max pump output is limited to 35W.
 
OP
M

Marck C

Hey John.g thanks for your quick and detailed response its just what I needed.. 👏 I will have a look at the settings you suggest in the morning and post back 👍
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Ok looked at it this morning at the heating was starting for the day.

I ran through the settings and this is what I got...
III - 45W
II - 19W
I - 6W
AuotpAdapt went up to 32W but quickly dropped to 12W
PP1 - 10 W
PP2 - 14 W
PP3 - 20 W
PP4 - 35 W

I might try it on PP3 for a while to see how it heats the rads, but PP4 seems to give the best Performance/Noise ratio for now.
 
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J

John.g

There is no PP4 setting so you might just see which setting is giving you 35W, IF PP3 is actually the setting pulling 20W then that may satisfy your requirements, it might be easier to just run through the PP and the CP settings again, PP settings depict a radiator and the CP settings depict a (UFH) pipework.
Post automatically merged:

Should have said PP mode depicts a sloping pump line and CP mode is a horizontal line.
 
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OP
M

Marck C

Hmm🤔 Confusing. I don't see the icons you mention o my unit. I've attached a photo of it... the four settings on the right are the ones i'm assuming are PP settings
 

Attachments

J

John.g

I've "found" your pump I think, see attachment. You have three constant curve settings (left hand LEDs...I,II,III) and two PP & two CP settings, (right hand LEDs...PP1,PP2,CP1,CP2). I have taken your readings and edited them below, I have also added the actual flows using the pump curves, you can see that CP2 gives, as you say, probably the best option but maybe worth giving CP1 a go as well. Once again Grundfos seem to provide, IMO, very poor settings but I think they are improving this with their new models.
For example, the three constant curves, which everyone in the world are familiar with are 1M,3M&6M, practically every other manufacturer would provide 2M,4M&6M, if you had the 4M setting available then you would run at ~ 25/27W which would have been be a perfect setting. Also the two PP settings of 1M & 3M are very poor as too low, should be ~3.5M&4.5M.
The CP settings of 3M & 4.5M are, again IMO, very good.
Auto Adapt....forget it.

III - 45W (6M)
II - 19W (3M)………….3.0M & 11.6 LPM
I - 6W (1M)
AuotpAdapt went up to 32W but quickly dropped to 12W
PP1 - 10 W (1M)
PP2 - 14 W (3M)……...2.0M & 10.3 LPM
CP1 - 20 W (3M)……..3.0M & 11.7 LPM
CP2 - 35 W (4.5M)....4.5M & 14.67 LPM
 

Attachments

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OP
M

Marck C

Hi John.g You are a legend!!! You're help has made a massive difference. Thanks so much, its very much appreciated. That makes perfect sense now! Iv'e just looked in on the pump and it was actually pushing at 27W on the CP2 setting for mid-day. That kinda sounds like where I'd want to be. But having said that I have changed it to CP1 and (it went to 20W) to see how it goes for a while. I will leave it on that for a day or so and see if I get a noticeable change in temps etc...

You've been immensely helpful 👏👏👍

I will post back on my final conclusion in a day or so.
 
OP
M

Marck C

Ok so (using the CP2 setting @ 20W) this morning the house reached temp fine by the time I got up. When all the rads were cold I turned the heating up a few degrees and within 10 minutes they had all reached a good (hot to touch) temperature.

So I'm going to stick with the CP2 setting..

Thanks again for your help John.g
 
J

John.g

CP1 is 20W not CP2 which was 35W...so which one are you on?? fixed speed ii also gives 19/20W.
 

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