Grundfos Alpha 2 Auto Adapt function

[Nigel Andrews]

I am a homeowner with only a little plumbing knowledge.
The house I have recently purchased has an Alpha 2 15-60 central heating pump with Auto Adapt
It is currently in the III setting and is providing hot water to the radiators.
But I am puzzled at the pump display which at every 2 min (appx), the power number, normally 36w-38w drops briefly and then the whole display clears to black. Then 88 appears followed by all the lights and indicators turning on. Which then gradually turn off, back to just the original 36w-38w number and III.
It's looking like there is a problem, firstly in that the number 36-38 is dropping and then the controller maybe is resetting!
I would try setting it to Auto Adapt, as that is the factory recommended setting, but I don't want to aggravate a problem. But maybe I have to call in a plumber?

Thanks
Nigel

 

[muggles]

The displayed number is the amount of watts of power it's currently using. 45 is the max IIRC but it will go down to about 5 when set to Auto Adapt if the system requires it. Auto Adapt saves you on your electricity bills.

As for why it's going off, could be a loose wire, a dodgy microswitch in a zone valve, or an issue with your boiler, depending on how it's wired. A simple way to test whether the pump is at fault would be to connect it to a 3-pin plug, plug it into a nearby socket or extension lead, and see whether it behaves itself. If it continues to flash on and off, it's duff. Might be under warranty depending on its age

 

[slippyr4]

Or it could be by design. I have the same pump and a potterton suprima boiler; the boiler has pump overrun and when it gets to the end of its cycle timer is momentarily cuts the pump power before it starts its ignition phase. THe "88" thing in the display and the rotating digits is just what the pump does

 

[Nigel Andrews]

Thanks both for your replies (I didn't get an email notification)
I did see it as around 45w (from memory) this morning when it started up again as there was demand for hot water and heating.
Are you suggesting it would be safe to select Auto Adapt (from III). This is a single storey bungalow of 2 bedrooms, two living rooms and two bathrooms.
The pump is wired direct into a wall outlet so I'd be reluctant to try and move that over to a plug, even if only temporary.
I need to understand if the indications are what the pump should be doing.
My boiler is also a Suprima though I'd have to check the exact model number.
Nigel

 

[slippyr4]

If you've got a suprima too then it's nothing to worry about.

On mine, auto adapt wasn't very good. But I run mine on the speed 2 on the right, which is adaptive, unlike thenspeeds on the left which are not.

 

[muggles]

I had a funny feeling you might say it was a Suprima. Does it have one light or two on the front? If two, you may well have a PCB fault (the ones with one light aren't hugely more reliable, but two-light ones are utterly rubbish). Budget around £300 to replace it if it is that.

Put it onto Auto Adapt and see how you go, it works well for most people

 

[slippyr4]

(mine has the replacement PCB and (still) does the momentary power off at the pump)

Auto-adapt doesn't work for me but this is likely because my CH is vastly underpiped. If I put it in auto adapt it runs at about 5 watts and the boiler goes in to overheat lockout. This may well not be the case for you!!

 

[Nigel Andrews]

The boiler I have has a side panel (a narrow flap that runs top to bottom) behind which I have seen a yellow light which turned green about 30-40 seconds after first switch on (alternating yellow/green just before). It also has a small temperature knob, but that is all.
OK I will try it on AutoAdapt and see what happens - but be prepared for some more messages!
Thanks for your help
Nigel

 

[muggles]

You have the newer PCB in that case. Without some electrical skills I fear you're not going to get any further in your investigations

 

[slippyr4]

You have the newer PCB in that case. Without some electrical skills I fear you're not going to get any further in your investigations

I am pretty sure there is nothing wrong with it - mine has always done exactly this. I have he exact same boiler and exact same pump. You only notice it happening because of the LED display on the pump.

 

[Nigel Andrews]

Thanks again.
It just seems, if the pump electronics are resetting, that it looks like a fault. As in if a PC reboots on it's own, repeatedly, that would be a fault.

I changed it to Auto Adapt and the numbers dropped to 3 and then slowly climbed (adapted?) upto 7, where it remains now. You are right though it hasn't changed the (approx. every 2 mins) resetting.

I would be concerned even if I called in a plumber, would he understand the problem and the pump?
He might say it needs swapping out when the system just needs some other adjustment. Maybe by changing it, it clears the real problem and appears to have been the correct solution. When the pump itself was fine.

Thank-you
Nigel

 

[slippyr4]

Watch the boiler as it runs:

1. In standby the light is orange.
2. When there is demand, first the boiler starts the pump
3. The boiler then goes through it's air proving and ignition phase, during which time the light flashes orange/green.
4. The light is solid green when burning
5. When the flow temperature is met (i don't mean that demand is met), the flame goes out, but the pump continues to run, and the light flashes green. Now, the anti cycle timer starts (2 minutes).
6. When the anti cycle timer finishes, the boiler starts the whole process again from step 2. It's at THIS point that the BOILER cuts the power to the pump for about half a second. I have verified this with a test meter.

This boiler cannot modulate - it runs flat out. That's why it cycles like this, particularly when your system is nearly up to temperature. The unusual thing is this half second power cut to the pump, but if you'd not had your pump replaced with the alpha2 you wouldn't even have noticed.

 

[Nigel Andrews]

OK that's cool. Thank-you for that breakdown of the sequence.
I am now more comfortable that it is working as it should.

Thanks again
Nigel