I replaced a 1 hp full speed pool pump with a dual speed pump
with the goal of hopefully substantially reducing the electric
power used. I was concerned if the pump would startup and work
with the solar heat on low speed. Testing has shown that it
will always startup and work when water is going to the pool
directly, ie non-solar. It will also startup and work OK if
the water is going through the solar heater, but only with
a clean DE filter, or one that is maybe halfway to needing to
be cleaned. Without a clean filter the pressure required is too
great. So, I'm going to put in the time delay relay system
that we discussed in the other recent thread to
have it start out at high, then switch to low. Once it gets
going on high, I can switch it to low in a minute or so and
it then runs solar on low fine.

I also did some power measurements by counting the revolutions
of the power meter for a few mins with the pump off, on high,
and on low. The pump is using 1/4 the power at half speed as
it does at full speed. This means if I run it twice as long
at 1/2 speed to move about the same amount of water, it will cost
about 1/2 as much. That's great news. Even better is that at
1/2 speed the pump is now perfectly matched to the amount of
time it should run for solar. Before for solar heating, it was
running about 9 hours a day at full speed, which is more than
was needed to keep the water clean. Now it will run 9 hours
at half speed, which is enough to keep the water filtered.
So, instead of just cutting the power usage by 1/2, I'm
actually cutting it to just 1/4. Should be saving about $55
a month in electric cost, making for a quick payback.

Also, found out something else interesting. Before measuring
via the power meter, I used a clamp-on ammeter. Looking at
amps going from full speed to half only cut the amps by just
a little over half. I new this wasn't accurate, but thought
that if the power factor was about the same at high and low
speed, then it would be a proxy for true power. But obviously
the PF must change substantially, because as reported above
as measured at the electric meter, the true power used drops
to 1/4 at low speed, not just by 1/2 as would be indicated
by measuring amps. I guess as the speed drops, more of the
power is reactive and less is real.

Bottom line, what I've measured is consistent with what I've
read about the substantial savings you can get by going to
a dual speed pump. In this case, all I had to change was the
motor ($180) and an additonal box, some switches, etc. Still
have to add that relay stuff. All in, probably cost $230
total.

On Wed, 21 May 2014 11:37:20 -0700 (PDT), trader_4
wrote:

I replaced a 1 hp full speed pool pump with a dual speed pump
with the goal of hopefully substantially reducing the electric
power used. I was concerned if the pump would startup and work
with the solar heat on low speed. Testing has shown that it
will always startup and work when water is going to the pool
directly, ie non-solar. It will also startup and work OK if
the water is going through the solar heater, but only with
a clean DE filter, or one that is maybe halfway to needing to
be cleaned. Without a clean filter the pressure required is too
great. So, I'm going to put in the time delay relay system
that we discussed in the other recent thread to
have it start out at high, then switch to low. Once it gets
going on high, I can switch it to low in a minute or so and
it then runs solar on low fine.

I also did some power measurements by counting the revolutions
of the power meter for a few mins with the pump off, on high,
and on low. The pump is using 1/4 the power at half speed as
it does at full speed. This means if I run it twice as long
at 1/2 speed to move about the same amount of water, it will cost
about 1/2 as much. That's great news. Even better is that at
1/2 speed the pump is now perfectly matched to the amount of
time it should run for solar. Before for solar heating, it was
running about 9 hours a day at full speed, which is more than
was needed to keep the water clean. Now it will run 9 hours
at half speed, which is enough to keep the water filtered.
So, instead of just cutting the power usage by 1/2, I'm
actually cutting it to just 1/4. Should be saving about $55
a month in electric cost, making for a quick payback.

Also, found out something else interesting. Before measuring
via the power meter, I used a clamp-on ammeter. Looking at
amps going from full speed to half only cut the amps by just
a little over half. I new this wasn't accurate, but thought
that if the power factor was about the same at high and low
speed, then it would be a proxy for true power. But obviously
the PF must change substantially, because as reported above
as measured at the electric meter, the true power used drops
to 1/4 at low speed, not just by 1/2 as would be indicated
by measuring amps. I guess as the speed drops, more of the
power is reactive and less is real.

Bottom line, what I've measured is consistent with what I've
read about the substantial savings you can get by going to
a dual speed pump. In this case, all I had to change was the
motor ($180) and an additonal box, some switches, etc. Still
have to add that relay stuff. All in, probably cost $230
total.

Trader,

About a few years ago I changed my pool pump out, doubled the filter
sq.ft. with a new filter system. Solar pool heat.

I went with the Pentair Variable Speed Pump and Hayward filter.
Against all the negative reviews. I sorted them out for the
solutions. This gadget can be programmed for 8 speeds. I only use 2
for now. Power bill went down. Prior to that I put in new efficient
HAVC units. I don't recall a recent high power bill. They used to
run ~$350 a month in summer.

Both save me money

On Thursday, May 22, 2014 4:31:23 PM UTC-4, Oren wrote:
On Wed, 21 May 2014 11:37:20 -0700 (PDT), trader_4

wrote:



I replaced a 1 hp full speed pool pump with a dual speed pump

with the goal of hopefully substantially reducing the electric

power used. I was concerned if the pump would startup and work

with the solar heat on low speed. Testing has shown that it

will always startup and work when water is going to the pool

directly, ie non-solar. It will also startup and work OK if

the water is going through the solar heater, but only with

a clean DE filter, or one that is maybe halfway to needing to

be cleaned. Without a clean filter the pressure required is too

great. So, I'm going to put in the time delay relay system

that we discussed in the other recent thread to

have it start out at high, then switch to low. Once it gets

going on high, I can switch it to low in a minute or so and

it then runs solar on low fine.



I also did some power measurements by counting the revolutions

of the power meter for a few mins with the pump off, on high,

and on low. The pump is using 1/4 the power at half speed as

it does at full speed. This means if I run it twice as long

at 1/2 speed to move about the same amount of water, it will cost

about 1/2 as much. That's great news. Even better is that at

1/2 speed the pump is now perfectly matched to the amount of

time it should run for solar. Before for solar heating, it was

running about 9 hours a day at full speed, which is more than

was needed to keep the water clean. Now it will run 9 hours

at half speed, which is enough to keep the water filtered.

So, instead of just cutting the power usage by 1/2, I'm

actually cutting it to just 1/4. Should be saving about $55

a month in electric cost, making for a quick payback.



Also, found out something else interesting. Before measuring

via the power meter, I used a clamp-on ammeter. Looking at

amps going from full speed to half only cut the amps by just

a little over half. I new this wasn't accurate, but thought

that if the power factor was about the same at high and low

speed, then it would be a proxy for true power. But obviously

the PF must change substantially, because as reported above

as measured at the electric meter, the true power used drops

to 1/4 at low speed, not just by 1/2 as would be indicated

by measuring amps. I guess as the speed drops, more of the

power is reactive and less is real.



Bottom line, what I've measured is consistent with what I've

read about the substantial savings you can get by going to

a dual speed pump. In this case, all I had to change was the

motor ($180) and an additonal box, some switches, etc. Still

have to add that relay stuff. All in, probably cost $230

total.



Trader,



About a few years ago I changed my pool pump out, doubled the filter

sq.ft. with a new filter system. Solar pool heat.



I went with the Pentair Variable Speed Pump and Hayward filter.

Against all the negative reviews. I sorted them out for the

solutions. This gadget can be programmed for 8 speeds. I only use 2

for now. Power bill went down. Prior to that I put in new efficient

HAVC units. I don't recall a recent high power bill. They used to

run ~$350 a month in summer.



Both save me money

I looked at the variable speed pumps. The big thing in their favor is
that you can select any speed you want. With my dual speed, I only
have full or 1/2 speed. It looks like it's going to work out OK here,
but if you needed higher flow, with your variable pump you could have it
run at 65% or to save even a bit more money, 40% if that works. They
are also somewhat more efficient just from the design, whatever speed
they run at. I can see why pros recommend them, because being able
to fine tune them means they won't run into some problem, particulary
with pools that are more complex.

The downside is the ~$1200 price, which is $1000 more than my motor
swap. And being ECM, they have electronics that I was worried might
get zapped, screwed, whatever, particularly in the somewhat hostile
environment, possibly leading to an early demise. My $200 swap should
be about paid for in a season by cost savings. Also the pump was only
8 years old, so it's still OK. If you need a new pump, then the equation
changes more in favor of the variable speed pump.

On Thu, 22 May 2014 17:17:09 -0700 (PDT), trader_4
wrote:

On Thursday, May 22, 2014 4:31:23 PM UTC-4, Oren wrote:
On Wed, 21 May 2014 11:37:20 -0700 (PDT), trader_4

wrote:


Trader,

I'd be curious if your conversion to dual-speed could get you a local
rebate for your utility company?

On Friday, May 23, 2014 12:46:31 PM UTC-4, Oren wrote:
On Thu, 22 May 2014 17:17:09 -0700 (PDT), trader_4

wrote:



On Thursday, May 22, 2014 4:31:23 PM UTC-4, Oren wrote:

On Wed, 21 May 2014 11:37:20 -0700 (PDT), trader_4



wrote:





Trader,



I'd be curious if your conversion to dual-speed could get you a local

rebate for your utility company?

No rebates for anything to do with a pool here. I think CA gives
rebates, but I think only for variable speed pumps, not dual speed.
And you're right, if you can get a rebate for the variable speed, that
also makes them more cost competitive.

I did some more calcs on the power used. The pump running at full
speed cost 25 cents an hour to run. At low speed, it's 6.5 cents.
Assuming you run it long enough to move the same amount of water,
I'd save about 1/2 the cost of electricity. And with solar, where
I was running it longer than needed to just keep the water circulated,
filtered, etc, I'll be saving 3/4 the cost.

As an example, when running solar, it was running about 10 hours
a day. That's $2.50. Now running it at 1/2 speed, it will cost
just $0.65. That's a 74% savings, $55 a month. Should pay off the
$230 cost quickly. I'll see how it works out as we go.

I just ordered the final solution, which is $20 for two relays
to make it always start up at high speed for a couple minutes, get
it primed and running, then go to low speed.