How can I turn on the second pump when enough zones open?

[MrEd]

My tarm is in the 'garage' on the first floor, with a grundfos 15-58 circ on the back, in the typical way. I have a second 15-58 in series with the first one (about 35 feet away) near the distribution manifold in the cellar.

My house has 5 zones (each with its own zone valve), when only 1-4 zones are calling for heat, the one pump does a fine job, but once that 5th zone opens, the water doesn't want to move (so I flip the switch on the second pump).

I could run both pumps all the time to solve my problem, but is there a type of circuit/relay setup that would tell the pump to run only if more than 'X' number of zones are open at the same time?

 

[bigburner]

current sensing relay, run the wire threw it that powers all the zone valve motors ( but no other loads) and set it for the combined load of the number of zones you want on before second pump comes on.

 

[wood-engineer]

You could put a relay on every zone valve & wire the pump in series thru the contacts - so when all (5) coils are energized, the pump will start.

Or you could get a cheap programmable controller/relay that will close an output (pump start) when all (5) inputs (zone valves) are on.

I can provide more detail info if you need it, just PM me.

 

[salecker]

Hi
Get a Grundfos Alpha pump.It will automaticly come on when it sences the zones opening.Falls into the KISS catagory.
That was the answer when i was looking for the same solution.
Thomas

 

[wood-engineer]

I just checked out that pump, it is pretty impressive (but pricey @ $240). It would do the trick - but might take a while to pay for itself in reduced energy usage.

 

[DaveBP]

I just checked out that pump, it is pretty impressive (but pricey @ $240). It would do the trick - but might take a while to pay for itself in reduced energy usage.

Patriot Supply sells them new for about $150. Compared to the price of Tekmar or other controllers it may be a savings over not so long a period but the electricity savings alone is not likely worth it.

http://www.ebay.com/itm/Grundfos-Al...124?pt=LH_DefaultDomain_0&hash=item2eb98faf64

 

[Steaming Pile]

How bout using the end switch on your zone valves (if equipped...most are) to activate a set of contacts??? Just throwing it out there.

 

[heaterman]

2 pumps + cost of control + wiring = more than the cost of a VS circ?