I remember seeing some chatter, it might have been on another forum, about the auto-adapt and CP/PP modes on these Alpha 2 pumps, in the end I and others ended up using one of the fixed speed modes (mine is set on II). The problem seems to be that the pump runs too slowly in the auto-adapt, CP or PP modes, the water overheats causing the boiler to cycle, and my rooms never get up to the set point. If I use fixed speed II then the water runs fast enough that the boiler stays lit, modulates down and the rooms quickly get up to their set points.
I had a problem yesterday where the boiler wouldn't fire when the only HR92s open where my bypass rad in the bathroom (which doesn't have a TRV) and my rad in the office where I work. So I applied a bit of thinking and thought "hmm I wonder if it's the flow rate"... so I opened the lockshield a couple turns on my bypass rad and sure enough the boiler fired and I started getting heat into the office radiator.
So this got me thinking a bit more about the pump problem... maybe I need to try the CP or PP setting again (looks like they recommend autoadapt or PP2) but this time open the lockshields and re-balance all the radiators - I wonder if this will get the flow rate up enough to allow the boiler to fire and stay lit. It will take a while but when only 1 or 2 rads are open I do hear quite a bit of water "whooshing" the open valves so I would prefer for the pump to back off a bit and it does bug me that I have an "intelligent" pump but I am using it in a non-intelligent way.
Has anyone else done this?
I had a problem yesterday where the boiler wouldn't fire when the only HR92s open where my bypass rad in the bathroom (which doesn't have a TRV) and my rad in the office where I work. So I applied a bit of thinking and thought "hmm I wonder if it's the flow rate"... so I opened the lockshield a couple turns on my bypass rad and sure enough the boiler fired and I started getting heat into the office radiator.
So this got me thinking a bit more about the pump problem... maybe I need to try the CP or PP setting again (looks like they recommend autoadapt or PP2) but this time open the lockshields and re-balance all the radiators - I wonder if this will get the flow rate up enough to allow the boiler to fire and stay lit. It will take a while but when only 1 or 2 rads are open I do hear quite a bit of water "whooshing" the open valves so I would prefer for the pump to back off a bit and it does bug me that I have an "intelligent" pump but I am using it in a non-intelligent way.
Has anyone else done this?
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