On Apr 23, 7:22*pm, wrote:
On Sat, 23 Apr 2011 13:38:33 -0700, Oren wrote:
On Sat, 23 Apr 2011 15:16:45 -0500, JimT wrote:

On 4/23/2011 2:19 PM, Oren wrote:
On Sat, 23 Apr 2011 12:34:59 -0500, *wrote:

Fancy electronics (unless cheap to replace) will eat up any energy
cost savings when the board fails. *

cheers
Bob

heh *If I'm reading correctly it looks like the board on the Pentair VS
is about $650.

http://www.poolpartsonline.com/p-815...drive-kit.aspx

The board is called a "drive kit"?

That's what it looks like on the blow-up. Part # 28. Price seems about
right to me.

http://www.amazon.com/PENTAIR-INTELL...COVER/dp/B002N....

Jim

Link: "Currently unavailable.
We don't know when or if this item will be back in stock."

I'm ruling out a VS motor for a long time G

If this strategy works, what is wrong with a simple 2 speed pump, or
even 2 pumps.

Nothing wrong with the simple 2 speed pump. That was the point
of my original post. It looks to me like you save the most on energy
usage by going with the variable speed, permanent magnet motor.
That saves about 70%, most of it because of the lower speed, the
rest because the motor is more efficient regardless of speed.

On the other hand, it looks like I can save about 57% by going with
just replacing the existing single speed motor with a dual speed
one. Can do that for $300, vs $900 for the variable speed pump.

The difference between 57% and 70% savings, given the pool is
run 3.5 months here, amounts to about $50. So, it would take
12 years to recover the additional $600 cost of the variable
speed. That plus the possibility of failure of the fancy drive
electronics, etc lead me to conclude the best solution is the
2 speed motor.



I am seriously thinking about going another way. I have been looking
at a DC pump, directly run from solar PV. That may be the best solar
PV idea I have seen. The more the sun shines, the more the pump runs
and that is also when you need it most.- Hide quoted text -

- Show quoted text -

That's an interesting idea. If you rig it together with a 2 speed
pump
so that solar is used just for low speed, might be a cost
effective solution. If it has to be able to run the pump at high
speed,
IMO it will be economically unviable because you'd need a lot
more panels. On the other hand, by my calcs, with the 2 speed
pump running on low, my electric usage will go from $340 a season
down to $150. At $150 a year in usage, I think it would take a
long time to pay back the solar system cost even for the smaller
array running the pump on low, probably rendering
it unviable here in the north with a 3.5 month season.