"My old Grundfos CH pump had seized after 17 years of faultless service. The new Alpha 2 L was a straightforward replacement and the use of a plug at the pump end of the flex made it a lot easier to wire up than the old one. I'm using it in "proportional pressure" mode where it should adjust its speed to provide just the flow required, and it seems to be doing just fine; gets heat to all the rads at startup but when only one rad is on there is no excessive noise at the TRV or pump. As for reliability, I can only base this on the 17 years I got out of the old one.
The only negative is the instructions; all pictures, no words. Hopeless in understanding the modes of operation. I ended up downloading a much better guide from the Grundfos web site."
"The last pump we had was noisy and less flexible. Very easy to install and quiet. The pump has a number of options that help to vary the flow depending on the time of year. The product was expensive compared to others but the has proved to be very reliable."
"Suffered with noisy pump for 12 months replaced with a new one which the plumber fitted on a angle therefore same problem for another 12 months decided to purchase this one the silence is wonderful pump is running great a bit expensive down to the same old you get what you pay for??. Would recommend this product and service at Screwfix."
"Excellent bit of kit. Bought one of these to replace my existing pump on my oil fired boiler. I have been having lots of issues with the boiler overheating since I fitted a underfloor heating kit. Once installed, I set to constant pressure and its been great. All my boiler issues now resolved. Not the cheapest but worth ever penny!!"
"Very good pump from Grundfos to replace my old pump, Not cheap but worth it for the performance, Very quiet when running and all radiators get hot quicker than my old pump could manage even when it was new. I contacted Grundfos Technical before fitting as it is a new type smart pump that can increase and decrease depending on the demand and they said the pump was suitable for my system and suggested the setting to use, Only took 1 hr to fit from start to finish, Great Pump and good advice from Grundfos."