grundfos alpha pump wiring??

hvac

Just wondering how everyone is wiring these pumps while zoning in circulators. I see most people are using them with zone valves and wiring the pump constant. Do these pumps need to be powered constantly? New to these pumps, my company is installing them with no training to the service techs. Thanks for any help!

hvac

grundfos alpha pump wiring??

also noticed the display flashes on some of the pumps when not in use! And when i say flashing i dont mean flashes between gpm and watts. Everything flashes. And this is your basic baseboard system!

ChasMan

Alpha

You can wire them either way. Constant or switched. I have mine on switched. I don't like the fact that they appear to boot up every time (ie the flashing) I will note however that even new out of the box, without powering them, just by spinning them a bit they will flash. This makes me think their is some sort of capacitor storing power for the auto adapt setting and the mode setting. They only flash a few times then they won't flash any more unless you power them up.

I emailed Grundfoss and they told me that the pump will retain it's settings between power on/off cycles however they did not say how long and what settings. It does appear on auto adapt they start out at a fixed speed and then over time slow down a bit. That slower setting is retained between cycles so I guess it works as advertised.

So, if you have them on a relay, and they shut oiff, if some water moves through them, then they will flash. Kind of silly.

hvac

alpha

Thanks for the quick response ..... It definitly makes sense now, I kind of figured there was some kind of power stored in there for the flashing to occur. Its gonna take awhile to get used to the behavior on these guys.

Gordan

Seems smart to me...

Since they shouldn't have flow through them when off. Could be an useful diagnostic trick to see whether you've got errant flow?

Zman

Switch it

This one has been on my mind lately. I had a chance to talk with the grundfos folks in Chicago. They say they can be wired either way but the "learning" part of the auto adapt would reset when powered off. I have been frustrated that the "auto adapt" seems to have trouble with small radiant zones (it doesn't recognize that the valve opens). Recently I have favored switching the pump and putting in "constant pressure" mode. I just set it as high as I need to get the desired gpm through the zone. I think it uses more energy when running but does not use standby wattage  the rest of the time.



On a side note Taco is gearing their pumps to run on delta T. Their point is that with the series radiators we see in the US remodel market, delta T is more important than delta p. The delta t pump is also a great solution for controlling fan coil water, as well as outdoor reset and setpoint mixing.