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[Cabo]

Upon Slimjim's suggestion, during OWB install I will change out my existing Grundfos 15-58 to an Alpha.  I looked at the 15-55 and it has very similar head range and a slightly higher max flow.  Is this the model # I should be getting or something else?  Thanks, Cabo

[Sprinter]

Question is can the zone you plan on putting the Alpha on make use of the Alpha features. It works best when the loop/zone has changing needs or pressures. Like when multiple zone valves open and close creating pressure differentials where the Alpha adapts to. Either way it's still an ECM circ that uses less energy and has multi speeds....

[Cabo]

Thanks for the response Sprinter.  I didn't explain the set up at all.  The current 15-58 feeds the manifold which has 7 zone valves (6 heat and 1 hot water).  The  variable speed would work well depending on the demand as the valves call for water.

[Sprinter]

7 zones is a lot for an Alpha, did you size everything? That is a perfect application as long as it can supply enough GPM/BTU

[RSI]

If the 15-58 is working well now then the 15-55 Alpha should be fine.

[Cabo]

I didn't size the pump.  The 15-58 has been on there for 3 years so far.  It replaced a Taco that failed after 2 years.

[slimjim]

Cabo, has a nice setup with all zone valves, if it were up to me we would rip all those darn zone valves out and replace with circs but that is not practical, it would be nice to split those zones up to 2 circs but at this point he has had no problem with enough flow so why fix what ain't broke, he's going to put a spare circ on the shelf and all circs will have ISO flanges on them.

[LittleJohn]

...at this point he has had no problem with enough flow so why fix what ain't broke, he's going to put a spare circ on the shelf and all circs will have ISO flanges on them.

Always beneficial to have isolation valves and spare pumps!!! Cause stuff always breaks at the least opportune time; cold night, deep snow and horrible roads (on a weekend)

Sprinter, the nice thing about zoning is that you don't necessarily have all loops open at once, in theory individual loops/zones will open and close as required to satisfy the thermostats.  That beign said, on design day or at startup in the fall all loops may be open and potentially increase the recovery time.

In my house, I have one Alpha feeding 7 zones of heat emmision plates under sub-floor (total of 12 loops covering 2100sf, longest loop at about 250')

[Cabo]

To do it all over again, I would put pumps in.  For years we used zone valves in all our houses.  Now all we go with are pumps.  Always looking for ways to improve the final product and this is definitely one area.  Like Slimjim said, if it ain't broke, don't fix it (eventually they will get changed out).

[NaturallyAspirated]

For the going price of an Alpha it almost makes sense.  You could get rid of a zone valve with actuator and a balancing valve and break even.

I may consider that....  hemm...

Neal