Just fitted a Grundfos Alpha 2 and have problems

[sotontotton]

Just installed an Alpha 2 pump and on autoadapt I experience kettling of the boiler (may need descaling) and more annoying after a few minutes a water rushing boiling sound from around the pump. The pump displays around 11watts when on autoadapt.

I have an old Gloworm Fuelsave II boiler with TRV valves fitted in the upstairs bedrooms and bathroom. Altogether I have around 5 radiators.

Any help would be much appreciated.

chris

 

[Boilerman2]

Thats the problem with adaptive pumps, they slow down when no load, fabricated boilers such as yours need a high flow rate at all times!!

try setting the pump to manual, or fit a standard pump

 

[sotontotton]

I'll set the pump to the adaptive pressure flow as that works fine and only uses 30Watts instead of the old pump that used 60watts.

Weird thing is if the pump is set to autoadapt and heating kicks in to move the temp by 1-2 degrees there are no problems at all. When the heating kicks in the morning and the temp has to rise by 5-6 degrees there is a hell of a boiling rumbling noise from around the pump/valve area. I think the whole thing just boils over.

Anyone else have any thoughts on it before I set it to adaptive pressure flow setting?

Chris

 

[gas4you]

These modulating pumps might look good on paper and in a 'perfect' demo system at the pump manufacturers, but out in reality they are a complete waste of time IMHO.

They cause many times more grief than the few pennies they will save you in running costs

 

[sotontotton]

The weird thing is that things start off ok once the heating starts and it's not until towards the end when the boiler/pump switches off that I get a boiling whooshing sound from around the pump next to all the other pipes.

Is it doing this becaue of a too slower flow rate? The only fix at the moment is to set the pump to speed 3.

I have got X400 in at the moment and wondering if that's causing the issue?

Anyway gonna drain the system and refill with inhibitor and noise reducer.

 

[Boilerman2]

As I have already said your new fangled pump is varying the flow rate, your boiler needs a CONSTANT FLOW RATE ... get it??

 

[sotontotton]

Yes I do get your answer, but I was wondering if anyone else had some constructive comments.

Get it?