Replacing spa pumps - sizing?

pgershon

Gold Supporter
Jul 15, 2012
283
East Hampton NY
Pool Size
30
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
I have a 20 year old 3000 sf gunite spa with its own plumbing next to my pool. The spa a 1.5 hp Hayward Super Pump powering the filter / pool heat / SWG. Filter is a Hayward C500 cartridge. Piping is 2" except for the in/out of the filter which is 1.5". The flow from the pump to spa is VERY strong and overkill, and I realize I should have bought a two speed pump last year and not a straight replacement when the pump died last year.

The spa also has 8 gunite jets fed by 2-2.0 HP Hayward Super Pumps, which are now leaking. I planned to replace the gaskets and shaft seal on the pumps and thought this would work, but as I removed the first pump, its seems to be pretty corroded and I have yet to get the back plate off (assume I'll figure that out tomorrow). But these pump motors will need replacement soon, if not now. Assume I am able to recover the wet parts of the pumps and only need a new motor.

Question - does it make more sense for me to simply replace the two 2 HP motors, or to try to downgrade the motors to 1.5 HP (and move the one year old 1.5 HP filter pump to the jets, replacing the filter with a two speed pump)? Can the existing non-motor parts of the 2 HP pumps (C48M2N111) take a 1.5 HP pump? And can the 1.5 HP power 4 spa jets (1.5 inch Hayward concrete inlets with Waterway gunite polyjets) or will I see a decline? I think the original builder overloaded the capacities of the pumps, but I really dont know how to check.

Thanks advance for your thoughts.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,023
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
does it make more sense for me to simply replace the two 2 HP motors, or to try to downgrade the motors to 1.5 HP
Hurry - single speed motors are no longer being manufactured for pool pumps in the US at that HP rating. So you have to get them from what is in stock. Or change them to VS motors.
 

pgershon

Gold Supporter
Jul 15, 2012
283
East Hampton NY
Pool Size
30
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Thanks. But how can I tell if a 1.5 ho pump would be sufficient to power 4 jets? Is more power always better?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,023
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Is more power always better?
Most spa jets are best to have about 10 gpm per jet. So you would need to get an approximation on how much water each type will put out.
 

pgershon

Gold Supporter
Jul 15, 2012
283
East Hampton NY
Pool Size
30
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
I just ordered two new 2-HP pump motors. Current ones still function but look rotted and ready to croak.

But I cannot get the back plate off my current pump to get the impeller and shaft. Any ideas? Screw completely fused.
 

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