Pump/Plumbing/Solar Questions

[jblizzle]

The current setup:
- Built in the 70s
- ~20000 gallons
- Hayward RS1500 pump with AOSmith ST1152 (1.5HP, 1.47SF) pump ... does this seem like a good pairing?
- Hayward DE6020 filter
- Raypac RP2100 gas heater (rarely used)
- Equipment pad 15' from skimmer at the water level
- 1 main drain plumbed to 1 skimmer to pad using 1.5" pipe (while the deck was ripped apart for the skimmer ... I probably should have run the drain directly to the pad huh?)
- Plumbing at pad is half 1.5" and half 2" ... planning to redo it all in 2"
- There are 3 1.5" return lines, but I only currently use 1 at a time.
- main return to 4x 1"(?) eye balls (normal mode)
- return to old whip cleaning system ~8-9 1" holes (never used)
- return to 3x 1" eye balls with air induction at bench seat (rarely used)
- DIY solar system with 60' 1.5" pvc run to single story house to 12 ~100' 3/4" black irrigation-like pipe randomly twisted around the roof. The roof is not as steep as typical roofs, but it is not flat either. Note this is currently plumbed AFTER the heater (??? I plan to change this)
- Normal clean filter pressure ~25psi (no-solar) or ~28psi (with solar)
- Waterfall that is Ts off off right after the filter with a separate ball valve (rarely used as a lot of the water does not make it back to the pool ... another previous DIY project I think)


The questions:
1. Does the current setup (pump/motor/filter/plumbing) make sense?
The pairing of a single 1.5" return with a 2.2HP motor on a RS1500 pump with a large DE filter seems off to me. If the suction plumbing is limited to <60 GPM, how am I supposed to feed a large filter that recommends a higher flow rate than that? Or is the large pump sucking the water through there FAST?

2. Can I modify the solar setup to what I want?
My desire was to replace the small DIY system with 11 4'x12.5' Heliocol panels (got a good deal on them used) ... plumbing of these on the roof may become another topic. I then got concerned that they recommend 5GPM / panel or 55GPM. Can I even get that amount of water to the roof with my current setup? Would increasing the plumbing size to the solar help or is the real limiting factor the single suction line? Would it help to replace about half of the suction line with larger pipe since replacing all of it would be a nightmare at this point?

3. Are plumbing and/or pump modifications required/recommended?
Given my current setup and my solar desires, would any plumbing changes be desirable? Could I benefit from a better pump?

4. Why didn't I think ahead last year when we resurfaced everything and replaced the skimmer?
Had I an forethought, when the skimmer was dug up and replaced due to a leak, I probably should have tried to plumb the main drain directly to the pad since I believe the suction is now my limiting factor.


One thought I just had was that there is a hole under the waterfall that does not appear to be used by anything. I am guessing (based on some cut wires nearby) that there used to be a separate pump on the waterfall. Maybe this sidewall could become another suction line? Although I would have to verify I can get access to the plumbing and I am not sure of the size. Also, I am not sure how I would cover it ... or if it is even safe to use a suction like that.

My long term plan is to add automation control with a SWG and solar control, although in the near term I am focusing on the manual solar option. The automation controller could then allow me to go to a variable speed pump if it made sense. I suppose I could use a low RPM when the solar is not on (like in the winter months) and use a high RPM for when solar is on.


So, hopefully this will get a dialog started. I was trying to figure out my current head and whether the pressures and everything currently make sense and got sidetracked when it appeared that my suctions line size ... basically sucks

 

[mas985]

Let me start with your questions:

1. First, there is no such thing as a flow rate limit for pipes only recommendations so the suction isn't really limited to any flow rate. Is it higher than than it should be for 1.5" pipe, probably. Also, for filters, lower flow rate is better. A 60 sq-ft filter should have no more than 120 GPM flow rate but would be better off less than 90 but I doubt that pump is anywhere near 90 GPM on that plumbing.

2. Flow rate should not be a problem with nearly any pump. I have a 1/2 HP running solar on a two story roof and get 48 GPM with 10% of the flow bypassed (55 GPM total). But my question is why so many panels for a 20k pool in AZ? You could get by with much less unless you are attempting to heat in the winter.

3. Changing any plumbing underground is going to be a pain so at this point, I think the objective should be work with what you have.

One thing I forgot to ask about was the height of the pump relative to the pool water level, higher or lower by how much. For now, I will assume it is the same level.

Also, the filter pressure seems a bit high for a single 1.5" suction line. Are there any valves on the pad after the filter? Does the pressure gauge go to zero when the pump is off (i.e. do you have confidence it is reading the proper pressure)?

A picture of the pad may also be helpful.

 

[jblizzle]

Thanks for the info.

So, I know see that having the larger DE filter is not a problem with a possibly lower flow rate than their recommended. And that with the large pump, it is likely sucking water through the one 1.5" at maybe a higher rate than recommended, but not really limited.

Regarding the number of panels ... the idea would be to extend the swimming season as long as possible. The roof while at a low pitch is also not exactly oriented ideally to the South so when I saw the deal for 11 of the panels and that happened to be what will fit, I figured more was better. Now I have also read that higher flow rates through the panels is more efficient, so if it turned out that using fewer panels and thus a higher flow rate would be better heating, then I have no problem not installing all of them ... I am sure I could resell them for at least what I paid.

I am interested to find out if my underground plumbing will indeed be enough. I was just not sure if replacing some of it (like the long run to the house for solar) with a larger pipe would actually help anything. I do think most of the pad needs to be redone anyways as it is kind of sloppy. I am not home during daylight, so I will either see if my wife can get a couple pix or wait until the weekend.

For now I will describe the plumbing as I remember it. Out of the filter through a Hayward 7-way then through 4x 90s, through the heater (there is no bypass, so maybe that is restricting? ... wondering if I should even keep this plumbed or not), through 2x 90s, a 90 through the solar valve, then either straight to the return manifold with a valve on each of the 3 returns or to the solar loop.

The needle does go to zero when off and where I have the indicators set shows that the clean pressure was 25 psi ... I think it was at 27-28 when I looked last weekend. I guess I am not 100% sure this is correct. Although this is still lower than my last house ... amazes me when I see people with pressures around 10-15 as I have never seen that low ... must be "bad" plumbing.

I think I will try switching between the return lines to see if the pressure changes. And backwash this weekend to see the effect. I don't see anything obvious that could be raising the pressure besides all the 90s and forcing full flow through the heater maybe.

The pump is literally at the water line, when I open the top, the strainer stays mostly full.

I am curious to hear what kind of head and pressures you think I should be seeing ... as I have seen you make very good estimates in other threads.

Thanks.

 

[mas985]

Initially, the model told me that you should have around 21 PSI and 71 GPM @ 73' of head. But in order to get 25 PSI, I needed to add 100' of 1.5" pipe and the operating point becomes, 63 GPM @ 77' of head which is a lot of head loss even for a 1.5" plumbing system. It could be on the high side due to something I am not aware of such as extra fittings or even the DE filter needing a grid cleaning. BTW. have you cleaned the grids recently?

The pressure on the filter will drop some if more than one return line is turned on. If the pressure doesn't change much when you turn all three return lines on, it is likely the filter or heater causing the extra head loss. If the pressure drops by more the a couple of PSI, then the issue is probably with that one return line.

 

[jblizzle]

The grids should be pretty clean ... in fact they are brand new with only the initial charge of DE. I have noticed the pressure raise a couple psi since their install so I will give it a backwash this weekend and maybe spray them down (although not going to take them completely apart again already).

And I will see what happens when everything is cleaned up and different return paths are tried.

The only other thing I can think of is that there was a leak in a pipe underground (can't remember which line ... might have been the normal return) that was repaired by 4x 90s in a U ... not sure how much head that would add. If that is pretty bad, what other method should be used to fix something like that where straight couplings can not be used? Is it ok to bury a union?

 

[mas985]

If you can dig out a long enough stretch of pipe, you can usually just bend the pipe enough to slip on a coupler. I don't think I would bury a union though. However, 4x90s has the same head loss as about 16 feet of straight pipe so it isn't all that much to worry about. The extra 100' of pipe I added is worth about 27 90s so it is a large amount of head loss.

As part of the baseline, I usually assume there are 5 90s underground for both the suction and return side plumbing.

 

[jblizzle]

I got a couple quick pictures of the pad this morning before work. Let me know if you can not follow anything. The blue ball valve is for the waterfall. The "green" 3-way valve is for the solar. When I get around to replumbing, I plan to actually put a real pad down ... story of this house, everything done half-Rear

Also did a couple quick pressure tests, apparently the filter is dirtier than I thought as the normal return pressure is now 30 psi. When I turn on just the whip return it was also 30. With both on it dropped to 28. With just the seat returns on it was 32 and with all on it was about 27.

One thing I did not test was turning on the waterfall. As I recall, the pressure is lower with it on ... that could certainly point to the heater being the restriction.

Need to clean the filter this weekend and check these numbers again.

Also noticed some small air bubbles going back to the pool :x Thought it might be the pump lid (I HATE the design of the RS pump) so cleaned and lubed the o-ring, but still noticed the air. Emptied the air from the filter and the bubbles went away, but I will have to see if they return after running for awhile.

 

[jblizzle]

Did a backwash today and then fell for the "valve not seated completely when switching to filter to recharge with DE so some undetermined amount was lost to waste" feature AGAIN :x So I added another 1.5 lbs or so. The seal is brand new, so I am not sure why this happens ... just have to wiggle it a bit and turn the pump on and make sure I do not hear a hissing of water through the 7-way valve.

Normal return pressure: 26 psi
Whip return only: 30 psi
Both returns: 22 psi
Normal return & waterfall full open: 14 psi
Waterfall only: 20 psi (this removes a lot of plumbing and the heater from the circuit ... kind of surprised this amounts to 6 psi difference)

I noticed that a couple of my leak repairs on the DIY solar have blown apart again (and I don't feel like fixing them if I am going to be replacing the solar anyway), so I can not turn that circuit on to check pressures. Although if I recall correctly, sending all the water through the solar gave a 2-3 psi rise.

So, ultimately, looking for thoughts on whether I can use 10-11 of the 4x12.5 heliocol panels with my current system. Would any relatively easy plumbing changes help? Could I get by with a smaller motor/pump or 2-speed or variable pump or is the likely savings probably too small to make it worth it if it has to work so hard to have the needed flow rates?

Anything else I should try to check out to evaluate my current system? I am not sure how the circulation will work toward the skimmer, but I could try to leave both return circuits open if that would help things.

Thanks,
Jason

 

[mas985]

Normal return pressure: 26 psi
Whip return only: 30 psi
Both returns: 22 psi
Normal return & waterfall full open: 14 psi
Waterfall only: 20 psi (this removes a lot of plumbing and the heater from the circuit ... kind of surprised this amounts to 6 psi difference)

This tells you that there is a lot of head loss on the pad and it is probably the heater so it might be a good idea to remove it as long as you don't think you will be using it.

So, ultimately, looking for thoughts on whether I can use 10-11 of the 4x12.5 heliocol panels with my current system. Would any relatively easy plumbing changes help? Could I get by with a smaller motor/pump or 2-speed or variable pump or is the likely savings probably too small to make it worth it if it has to work so hard to have the needed flow rates?

It should not be a problem to run the solar panels with your current setup but since you are replacing the panels, it might be a good idea to clean up the pad plumbing as well. If you don't need the heater, remove it. Go with at least 2" pipe. As for downsizing the pump, that should not be a problem given the setup although I wouldn't go any smaller than a 3/4 HP full rated pump. A variable speed makes "optimization" easier and gives you more choices in flow rates but the lifetime cost will probably be higher than a two speed for Az electrical rates. Keep in mind that it may be desireable to have higher flow rates for solar to maximize efficiency but it isn't always necessary either. In Az, there will be many times where you have too much heat and running a slower speeds would be desireable.

BTW, how high is the roof where the panels will be installed?

 

[jblizzle]

The waterfall alone has the least plumbing as right after the filter valve it goes directly to the pool. So, the extra plumbing and heater and longer run around the pool to the 4 eyeballs is adding 6 psi.

I am torn about removing it as we have used it occasionally when swimming with the water not quite warm enough ... nice to have the "hot spots" . But, with the better solar heating, it may not be needed nearly as often. I was planning to try to better organize the pad and use all 2"+ ... Is there a benefit/need to add a bypass between the inlet and outlet of the heater that I could open and reduce the flow through it when it is not needed?

So what is my motor now? A 2.2 Hp full rated (I still get a bit confused by this). Are you stating you think I could get by with a Hp *SF >= 3/4 Hp? That could still get me ~55 GPM to the roof? That seems crazy to me given how big all the pumps I have seen in AZ ... I guess they are just all over-sized (although my last house had a Spa so that was probably the reason for it).

The roof at the low end is 9' and the peak is 11' ... maybe add another foot for the pool and pad being slightly lower.

I agree when I look at the electricity rates here, I can not see the benefit to the variable pumps. As it I think I am paying maybe $60/mo. Even if I could save half that, it would take quite a few years to break even. A 2-speed could make sense so that I could run low-speed when the solar was not needed (both in the summer and in the winter) ... although if I add a SWG I would obviously have to be careful with this ... do they generally not work on low speed?

Thanks again.

 

[mas985]

According to my database, the pump you have now is a 1.5 HP up rated pump with a service factor of 1.33 and has a THP of 2. This is equivalent to a 1 HP full rated pump. Stepping down to a 3/4 HP full rated pump is not much of a change in terms of flow rate.

I am estimating (with 26 PSI now) that your current pump is producing about 60 GPM @ 78' of head. Going with a 3/4 HP full rated Whisperflo on your current plumbing would produce about 55 GPM @ 65' of head. Fixing the pad plumbing and putting in a heater bypass could increase the flow rate to 65 GPM @ 57' of head. With solar engaged, I estimate about 55 GPM @ 65' of head. Solar adds head but changing the pad plumbing will reduce it assuming you minimize the number of fittings and bypass the heater. These are all estimates and your results may vary but it hopefully gives you an idea how things may change. Plus you have the option to turn on the waterfall and the bench sheat which will increase flow rate through the planels by reducing head loss.

Also, when replumbing, you should add a check valve right after the filter. Use one of the Jandy flapper types for lowest head loss. Also, put a solar valve right after the check valve and feed the solar from that point. You can plumb in the waterfall return after the solar return. This will keep the pressure in the solar system high enough so that the vaccum release valve remains closed and help the panels prime quickly. It will also maximize the flow rate through the solar panels even when the waterfall is on.

 

[jblizzle]

According to my database, the pump you have now is a 1.5 HP up rated pump with a service factor of 1.33 and has a THP of 2. This is equivalent to a 1 HP full rated pump. Stepping down to a 3/4 HP full rated pump is not much of a change in terms of flow rate.
/quote]

According to the label on the motor, it was likely a replacement since it is a AOSmith 1.5HP 1.46SF for a 2.2 THP. Do you have a typo in the above quote? Should it be "This is equivalent to a 2 HP full rated pump"? Are the full rated pumps usually with a SF of 1? I guess I need to go back and review your Pump sticky to make sense of this.

Dropping from a 2.2 to a 3/4 seems like a huge jump ... but you say this does not affect flow rate much?

Thanks for the tips on a re-plumb. It is also typical to put a check valve on the return from the solar right? I will have to review some of the schematics on the site and others on the internet.

I think at this point, I will try to plan out redoing the pad and installing the new solar panels (since it sounds like everything should work) although I need to do some roof work first. Then maybe think about switching to a smaller pump in the future.

Would you recommend just a single speed 3/4HP Whisperflo or do you think I could benefit spending the extra $150 on the 2 speed model? Any idea if a SWG would turn on for the low speed? Do you have the Wattage use between the high and low speed? When not using solar, the low speed could work, but if it would not turn on a SWG then that may not bee too helpful.

 

[mas985]

According to the label on the motor, it was likely a replacement since it is a AOSmith 1.5HP 1.46SF for a 2.2 THP. Do you have a typo in the above quote? Should it be "This is equivalent to a 2 HP full rated pump"? Are the full rated pumps usually with a SF of 1? I guess I need to go back and review your Pump sticky to make sense of this.

The motor was likely replaced at one time. You can replace a motor with a larger motor but not the other way around. First a few definitions:

THP = Total HP = Label HP * Service Factor

The orginal motor had a label HP of 1.5 and a service factor of 1.33 so the total HP or THP is 2.

The full rated version of a motor will have a lower HP but a higher service factor than an up rated motor but their THPs are idential. So a full rated 3/4 HP pump is the same as a 1 HP up rated pump from the same pump line.

Dropping from a 2.2 to a 3/4 seems like a huge jump ... but you say this does not affect flow rate much?

Not really. First the orignial THP for your pump is 2.0. Second, the THP for the Whisperflo is actually 1.24 = 3/4*1.65. And lastly, the THP of a motor only reflects the maximum HP rating that the motor can deliver. Flow rates are loosly related to THP but by the cubed root of THP so it takes a very large change in THP for a small change in GPM. This is why a higher HP pump uses much more energy per GPM of flow rate. To really understand the flow rate difference, you have to look at the pump's respective head curves. But on exactly the same plumbing system, the Whisperflo will deliver only about 10% less flow rate so not much of a change.

Thanks for the tips on a re-plumb. It is also typical to put a check valve on the return from the solar right? I will have to review some of the schematics on the site and others on the internet.

Yes, that is to prevent back filling of the solar planel when the solar valve is in the off position.

Any idea if a SWG would turn on for the low speed?

Yes, an SWG should turn on with flow rates as low as 15 GPM. Your low speed will be running at about 32 GPM so you have plenty of margin.

Do you have the Wattage use between the high and low speed?

With the Whisperflo and using my estimates, high speed should be around 1600 watts and low speed around 360 watts. Low speed is half the flow rate as high speed so assuming you compensate with a longer run time, you will save ~55% in energy costs. Your old pump is probably using around 1900 watts.

Would you recommend just a single speed 3/4HP Whisperflo or do you think I could benefit spending the extra $150 on the 2 speed model?

A two speed pump is definitely worth the extra money. You will save about 1/2 of the energy costs on low speed vs high speed. Plus during the summer, you will find that you won't need to run solar very much so you can save quite a bit of energy.

Assuming 1 turnover per day and $0.10/kwh, your old pump would cost about $30/month. Assuming 1/2 a turn at full speed and 1/2 a turn at low speed, the Whisperflo would cost $18/month. So saving $12/month you could easily pay for the extra $150 in a year's time.

 

[jblizzle]

Suppose I will keep my questions together as they are sort of related.

Starting to try to plan the plumbing for the solar on the roof. Having to put banks of panels on 2 different sections of roof that are a gentle slope but the angle is 90 degrees to each other (there is a valley interface between them).

Is it typical to just use a short piece of the flexible PVC for this transition or am I better off avoid the flex stuff and just trying to get a 90 to work?

Also how much does a bank of 4x and 6x 4x12.5 panels need to be angled on the roof so there is a "high side" to ensure the air gets out?
Seems like if my plumbing is perpendicular to the roof slope to allow the use of a 90 between slopes, I would have to add some bend to something to make the connection to the panels. I can picture how everything could fit together nicely if all is square, but the tilt of the panels seems like it will add stress to something.

I really need to get a picture and sketch together to see if my plans pass the expert's eyes on the forum

Thanks.

 

[mas985]

Is it typical to just use a short piece of the flexible PVC for this transition or am I better off avoid the flex stuff and just trying to get a 90 to work?

You can use whatever is easiest. Having flex PVC above ground is not much of an issue. Most do not like to bury in case it needs to be replaced. Also, they are making much better flex now so if you do use it, don't go cheap. Also don't forget, you can also use multiple 45's if that makes it easier.

Also how much does a bank of 4x and 6x 4x12.5 panels need to be angled on the roof so there is a "high side" to ensure the air gets out?

This really shouldn't be much of an issue even if they were perfectly horizontal. The panels should be fed from the bottom so the air will naturally want to travel up the tubes as the bottom header fills up. The air will then escape into the top header and out the return pipe. So if any air were to get trapped, it would probably be in the top header pipe at the closed end but that is not all that critical anyway. Usually, tilting the panels is more for proper draining than trapping air because of potential freeze damage. It wouldn't hurt to tilt the panels very slightly so they will drain properly. That will also insure proper filling as well. The bigest issue is where there are low points in a run of connecting pipe were water can sit and freeze. But I am assuming you aren't too worried about freezing.

 

[jblizzle]

Well, I got around to making a basic drawing of my solar panel plumbing plan to see if anyone can offer better ideas.

-The roof is probably a 2/12 pitch (if that much ... pretty flat).
-There are existing 1.5" pvc pipes that go through the eaves/roof. I will quickly transition to 2" plumbing on the roof to match the panel headers and reduce loss. I also was also going to add ball valves on both as they go up the wall to isolate in winter. (Needed?)
-There is no way to fit the panels and have the existing pipes from pool be the low point ... so I figured I would add a spigot drain at the low point for the couple of months that I might see cold weather to drain everything.
- Currently not planning for any tilt on the banks, but I am not sure how much play there may be in the plumbing to allow it.


QUESTIONS:
- See anything wrong with the layout?
- Are ball valves on the vertical pipes to the roof needed for isolation?
- Should I put "equalizing" ball valves on the roof? Not sure which banks will have more flow initially.
- If I do not have any slant to the banks, will they still drain daily down to the point where the inlet pipe comes through the roof?
- Is that the proper place for the Release valve or should I have one on each bank?
- What is the best way to anchor the PVC to the roof for support?

Thanks for your help.

 

[mas985]

- Are ball valves on the vertical pipes to the roof needed for isolation?

They can be useful when you have to work on the panels while the pool pump is running and for winterizing if you want to prevent the panels from filling.

- Should I put "equalizing" ball valves on the roof? Not sure which banks will have more flow initially.

I wouldn't. Water will seek it's own path of least resistance so the 6 panels will naturally get more water than the 4-panels. Besides, I never like the idea of restricting flow rates for just balance. It isn't very energy efficient.

- If I do not have any slant to the banks, will they still drain daily down to the point where the inlet pipe comes through the roof?

If the roof is practically flat, then there could be places where water will remain in either the pipes and/or panels. Some of the water will likely get siphoned out as they drain but it won't be perfect. Do you get freezing weather there? Even if you do, the good news is that a partially filled pipe may freeze but I seriously doubt it would cause any damage because it would be nearly impossible for an ice dam to form in the pipe.

- Is that the proper place for the Release valve or should I have one on each bank?

A second VRV near the 6-panels might help some to keep them draining at the same rate and to maintain a siphon for as long as possible. But that might affect the draining of the long return pipe so if you can have any pitch in that return pipe in either direction, that would help to drain that pipe. Really, you have to look at your setup edge on and see where the water will collect. It isn't a huge issue like I said because it would be nearly impossible for a partially filled pipe to break due to freezing.

- What is the best way to anchor the PVC to the roof for support?

That kind of depends on the type of roof. But I think for many installations, PVC u-clamps work well but you will need to penetrate the roof so use a good roofing mastic to seal the holes.

 

[jblizzle]

With the Whisperflo and using my estimates, high speed should be around 1600 watts and low speed around 360 watts. Low speed is half the flow rate as high speed so assuming you compensate with a longer run time, you will save ~55% in energy costs. Your old pump is probably using around 1900 watts.

Would you recommend just a single speed 3/4HP Whisperflo or do you think I could benefit spending the extra $150 on the 2 speed model?

A two speed pump is definitely worth the extra money. You will save about 1/2 of the energy costs on low speed vs high speed. Plus during the summer, you will find that you won't need to run solar very much so you can save quite a bit of energy.

Assuming 1 turnover per day and $0.10/kwh, your old pump would cost about $30/month. Assuming 1/2 a turn at full speed and 1/2 a turn at low speed, the Whisperflo would cost $18/month. So saving $12/month you could easily pay for the extra $150 in a year's time.

So, a new feature of my existing pump motor is that it is HOT. It had been warm, but over the weekend I was starting to notice a smell as I walked by and it was Very HOT to the point that I actually noticed it shut down (after cooling off for a bit it was able to start up again, so not totally dead yet). Glad it did not start a brush fire :-D

So, since a similar replacement motor is ~$250 and that fact that I HATE the stupid lid design on the RS pumps (always spitting out water on shut down and maybe pulling in a bit of air when running), I am seriously considering heeding advice here and getting a 2-speed Whisperflo.

According to some docs I found, my current AOSmith is ~9.2 amps @ 230V = 2100 watts. The 3/4 full rated Whisperflo is 14.6/4.7 amps @ 115 = 1680 / 540 watts which would give a 35% savings running on low speed. Am I doing some math wrong to not match your above estimates or am I missing something?

I see that the 3/4 HP version appears to only be 115V while the 1 HP is 230V like my present motor ... should I care if I drop to 115V or are 230V more efficient? Although I understand that the 1 HP would still use more watts.

Given my current plumbing and solar (and assuming I can not fix the pump pad plumbing too well to reduce head ... although I plan to try), is there any doubt that the 3/4 HP may end up too weak for me? I would rather spend the extra $40 now for the 1 HP than have to switch from a 3/4 to 1 later, although I realize my energy costs would go up, but if they have to then that is what I will live with.

I still plan on adding SWG and solar control (probably in an automation set). Assuming I get the Whisperflo, is there any reason I should go with a Pentair SWG and automation and not the Hayward SWG and automation? I already have some of the components for the Hayward SWG (plumbing, switch, cell ... I sold the controller with the intent to get the ProLogic) and wondering if I should try to sell them if I would be better off going Pentair (although not planning to replace the Hayward DE filter at this point).

Thanks again.

 

[mas985]

According to some docs I found, my current AOSmith is ~9.2 amps @ 230V = 2100 watts. The 3/4 full rated Whisperflo is 14.6/4.7 amps @ 115 = 1680 / 540 watts which would give a 35% savings running on low speed. Am I doing some math wrong to not match your above estimates or am I missing something?

Label ratings are for the motor's maximum amp draw but in most cases a pump will draw less than that. My estimates come from actual measurements done for the California Energy Commission. However, the savings you realize depends on how much time will be on high speed vs low speed.

I see that the 3/4 HP version appears to only be 115V while the 1 HP is 230V like my present motor ... should I care if I drop to 115V or are 230V more efficient? Although I understand that the 1 HP would still use more watts.

No, the efficiency of a pump is about the same on each voltage. However, you will need a neutral wire which should be available if you have a subpanel near the pump but check before purchasing.

Given my current plumbing and solar (and assuming I can not fix the pump pad plumbing too well to reduce head ... although I plan to try), is there any doubt that the 3/4 HP may end up too weak for me? I would rather spend the extra $40 now for the 1 HP than have to switch from a 3/4 to 1 later, although I realize my energy costs would go up, but if they have to then that is what I will live with.

Since you have to plumb the solar and replace the pump, why wouldn't you redo the pad? You will be changing much of the plumbing anyway. However, given a one story roof only requires about 5 PSI of filter pressure to keep the VRV closed and the Whisperflo is likely to have close to 25 PSI of pressure, there shouldn't be any issue at all.

I still plan on adding SWG and solar control (probably in an automation set). Assuming I get the Whisperflo, is there any reason I should go with a Pentair SWG and automation and not the Hayward SWG and automation? I already have some of the components for the Hayward SWG (plumbing, switch, cell ... I sold the controller with the intent to get the ProLogic) and wondering if I should try to sell them if I would be better off going Pentair (although not planning to replace the Hayward DE filter at this point).

Personally, I prefer the features of the Hayward SWG including a more accurate salt reading over water temperature. If you are planning to get a solar controller, you might want to look at a all in one controller/solar/SWG. Both Hayward and Pentair have them.

 

[jblizzle]

- I kind of guessed that the power consumption may be less than the label thus the numbers you quoted.
- I do have a subpanel at the pad, so rewiring for a 115V pump should not be too much of a problem.
- I plan to redo the pad ... just not sure exactly how much more efficient I will be able to make it ... figured worst case is the plumbing I currently have and if the 3/4 pump will work for what I have now any improvement I can make will just help.
- Good to hear about the Hayward. I had bought a full Hayward SWG setup and then decided I wanted solar control. So, I was looking at their all-in-one ProLogic automation and that is when I managed to sell the stand-alone SWG controller and still have the cell to use with the all-in-one setup. With the change to a Pentair pump, I was just curious if maybe there was an advantage (for example longer warranty if you had enough Pentair components ... though I had read that here somewhere) to leaning Pentair. That said, I was hoping to avoid having to sell the Hayward parts I have.

Not sure I can afford to do all of this at once, but the pump does not seem like it will wait much longer.

Do the Whisperflo not use unions like my Hayward pump?
Looks like they just have female threads ... any point to also adding unions near the pump?