I am installing a new radiant heating system. The system will have a buffer tank, 7 zones/thermostats, and about 12 valve controlled loops spread amongst the 7 zones. The water requirement at the design temperature is about 4.5 gpm. I'd like to install an Alpha pump. I think that in non-Alpha cases I'd need a relay so that the thermostats or zone valves could switch on the pump when there's a call for heat. However, I believe that with the Alpha, I can decouple the pump from the valves, and just set the pump to run at a constant pressure. So, when all of the valves are closed, the pump would simply wait until a valve opens to start circulating water. Am I missing something when I think that I can do away with the relay, and all of that wiring? Thanks, Jeff

we use the relay, but you're right, you can avoid it if you like. I believe in standby the unit uses about 5 watts. use autoadapt. the constant pressure modes appear to have higher minimum draw rates.

Thanks Rob. Question: Why do you wire it in if you can do it without - to save the standby power cost? If you do that, do you cut the power cord that comes with the Alpha? I was under the impression that one "couldn't" cut that power cord!

Jeff

yeah, though I suppose the transformer we need for pump relays probably draws about as much as the alpha does. it's primarily just for control so we can run it when we want to run it, and NOT run it when we don't. but that isn't to say it's wrong to do it the other way.

we relay the outlet box itself, we don't cut the cord.

Duh (on the box/cord thing.)

Thanks,

Jeff

Hi Rob,

Do you happen to know of any other ECM pumps, especially ones that have decent track records? The Alpha seems like a nice one, but at $250 more than a $100 Taco, it's hard to justify its usage (based on energy consumption) for anything that's not pumping a high percentage of the time.

Jeff

there are no cheap ones. however, if you are doing a multi zone system, it can eliminate the need for a pressure bypass valve which makes it economical again, especially since the pump would run most of the time.

also, I forgot: the alpha has 3 fixed speed modes. If you are using them, you need to turn the pump off and on like a regular pump. Since low speed gives you 3 GPM and 3 ft of head for 5-8 watts of power, it is an attractive mode for many uses. hard to beat 8 watts max pump power, for sure.

The alpha pump is designed to not have a relay installed, its ability to speed up on demand provides the needed GPM. I would use this in any application that has multiple zones. sure it is more money, but consider the savings in energy, the 3 year warranty it comes with where taco only has one year. it does more than than just speed up it has other settings also. not to mention the time a tech has to spend wiring up all those end switches, which you are familiar with those, they are trouble some at best. especially the manifold mounted types. spend the money its well worth it.

To be fair, Ground Loop, I was not asking about alternatives for the "heating loop" pump, as I (for one) am sold on the "no relay" and "no realy wiring" aspect of the pump. I was wondering if there were ECM pumps that are less expensive than the Alpha that could, for example, take the place of a boiler pump (an 007). If my boiler pump is only on 25% of the time, my 007 is only going to cost me about $35 / year to run. Spending $300 on an Alpha to save $20 / year is perhaps not so much of a slam dunk.