ALPHA2 15-55F Cast Iron Circulator Pump w/ Terminal Box

This is a very good pump and the related products that I got with it are of very good quality. Would purchase them again when needed.

Yeah, i replaced my old stainless steel UPS 15-55 ( circa 2009) with this motor head. I.e., i reused the existing volute by putting in this alpha head/ motor into it via the 4 caps screws. All UPS pumps will do this, btw. I have non 02 barrier pex in a radiant floor system; it was an open system at 1 time, and everything has to be non-ferrous, including the expansion tank, otherwise it will get eaten out. Boiler is Challenger CC85S. It's 1 zone and i run it on auto-adapt and it honed in on 8 gallons/minute at 38 watts. I do not run a primary loop,.. it is not needed at this flow.

Pumps seems to be working as it should, and looks great. Price point was better than what local supply stores are asking for this pump.

What's not to like about this pump? The AutoAdapt feature is amazing and is worth the premium over a plain Jane three speed pump. For info, my hydronic heating system which is several Euro style radiators (with TRV) on a Viega 12 port stainless steel manifold. There is a TSTAT centrally located in the house to tell the pump to turn on/off and to fire up the boiler. Room by room control is done by the TRV so the TSTAT is just a glorified switch. This pump is great because the AutoAdapt setting will automatically throttle down the pump speed if the radiator TRVs modulate closed (ie reducing flow thru radiator). This saves a lot of energy. The pump only uses a few watts during steady state operations and will sometimes throttle down to zero watts if the radiators are not calling for heat but the TSTAT (which controls the pump) is calling for heat. If it was a normal three speed pump it would try pumping water to the radiators even if the TRVs were modulated closed which could result in the pump deadheading (worst car) or just waste a lot of energy. I think this pump can save a lot of folks money on their power bill even if you have a more traditional radiator system like a mono flow tee. Highly recommend!

I have a relatively new house with two zones each requiring a circulation pump. Grundfel Alphas were installed by the original HVAC folks. First one failed within three years, and the house constructors didn't have any paperwork for a warrantied replacement; the other failed a few months after that. This year one of the replacement pumps failed, again the symptom is a "--" on the screen and a click every 7 seconds as the motor relay fails to start. Can't blame it on sediment in the water water - we are on city water. So 3 failures in 5 years - I would switch to a different brand if it had the same specs. The pump may look all clean and shiny with a fancy screen, but it's a lemon. BEWARE!

I like being able to tune the system with the pump or just let the pump do the tuning.

Everyone thinks of combustion efficiency. Very few think of electrical efficiency. Circs run thousands of hours a year. If you have one running at 90 watts or another a 30 for thousands of hours a year it adds up to savings. We're currently installing a system with 4 pumps. The savings are significant. And these pumps are reliable. We've been installing the Alpha pumps for about 5 years without a failure yet.

good stuff and great service

My radiant floor heating system had too much water flow when just one zone was calling for heat, now this smart pumps adjust the flow based on the demand for flow. Completely fixed my flow problem.

I use this pump on all my new installs. The customers like seeing the display and it allows me to know the pump is working correctly and efficiently.