Hello,
My plumber installed an Alpha 2L 15-60 and not an Alpha 2 as requested (and thus we don’t have the autoadapt feature).
I have a feeling there is less overall output now (not all rads getting as hot), as per my previous old fixed 15-60 pump – an earlier Grundfos model.
I need to work out if I get the plumber to upgrade to the Alpha 2 (Autoadapt), or try to get the right setting on the Alpha 2L
We’ve a reasonably large 5 bed house, with a new 30kW condensing boiler. I’ve done a rough calculation, and I believe we have a flow rate requirement of 0.6 to 0.7 m/s
I have a 2 pipe system with manual bypass – so I am lead to believe this should be proportional pressure. (PP2, PP1). The recommendation is for PP2.
If I’m reading the performance chart correctly, this means a max flow rate of roughly 0.58 at a head of 3 (the higher of the two blue lines). This may be why I am feeling the rads are underpowered.
If I use the PP1 setting (lower blue line), then I could get upwards of 0.75 at a Max head of 2. However, if the pump follows the lower blue line, then at 0.6 flow it will operate at a head of approx. 1.8. I do not know if this would be enough for the index circuit.
If I switched to the Autoadapt model, from what I can see, at 0.6 flow, it could operate at a 2.5 head (i.e. on the III line)
My theory is that
- If current PP2 setting is not enough, switch to PP1 – but since this stick to the lower blue line, I may not get the required head for the flow rate at the far right end of the line. i.e. at flow rate 0.6, this is a head of approximately 1.8
- I could switch to Alpha 2 with Autoadapt – in which case it would move along the III line until it found the correct balance – i.e. at a flow of 0.6 the head is 2.5
Is my logic correct?
Thanks
Alpha 2L performance chart
View media item 61277
Alpha 2 (Auto adapt works in green area)
View media item 61278
My plumber installed an Alpha 2L 15-60 and not an Alpha 2 as requested (and thus we don’t have the autoadapt feature).
I have a feeling there is less overall output now (not all rads getting as hot), as per my previous old fixed 15-60 pump – an earlier Grundfos model.
I need to work out if I get the plumber to upgrade to the Alpha 2 (Autoadapt), or try to get the right setting on the Alpha 2L
We’ve a reasonably large 5 bed house, with a new 30kW condensing boiler. I’ve done a rough calculation, and I believe we have a flow rate requirement of 0.6 to 0.7 m/s
I have a 2 pipe system with manual bypass – so I am lead to believe this should be proportional pressure. (PP2, PP1). The recommendation is for PP2.
If I’m reading the performance chart correctly, this means a max flow rate of roughly 0.58 at a head of 3 (the higher of the two blue lines). This may be why I am feeling the rads are underpowered.
If I use the PP1 setting (lower blue line), then I could get upwards of 0.75 at a Max head of 2. However, if the pump follows the lower blue line, then at 0.6 flow it will operate at a head of approx. 1.8. I do not know if this would be enough for the index circuit.
If I switched to the Autoadapt model, from what I can see, at 0.6 flow, it could operate at a 2.5 head (i.e. on the III line)
My theory is that
- If current PP2 setting is not enough, switch to PP1 – but since this stick to the lower blue line, I may not get the required head for the flow rate at the far right end of the line. i.e. at flow rate 0.6, this is a head of approximately 1.8
- I could switch to Alpha 2 with Autoadapt – in which case it would move along the III line until it found the correct balance – i.e. at a flow of 0.6 the head is 2.5
Is my logic correct?
Thanks
Alpha 2L performance chart
View media item 61277
Alpha 2 (Auto adapt works in green area)
View media item 61278