Variable speed pump control

[Gary.B]

Following on from my earlier Introduction, here we go with my first query.
For background pool runs 12 hrs per day 365 days a year, the 12 hrs from end of September to end of April because the pool is heated thru the winter months, 12 hrs for the rest of the year because It's a vacation rental and apparently the guests like to see the water features running and pool water moving. Pool and Spa share the same pump.

Current single speed 1.5 Hp pump motor bearings are getting noisy and because of the pool run times running costs are huge. So looking to install a Pentair Variable speed, probably the 011018, I like the way it's built and it gets pretty good reviews, although being an Engineer the fluid dynamics of the XF pump head are impressive/ tempting, although both will be an overkill for my pool in potential full capacity, but should save a considerable amount running on a slower speed, although I will be surprised if anything like the online calculators would have you believe.

Now the problem, I have an analogue Intermatic controller/timer that runs the pump, Hayward NG heater, Spa change over valves etc ( Spa is on a mechanical timer). I first thought I could use the Pentair Intellicomm II and just connect via a relay from the Intermatic direct to the pump converting the analogue signal to digital and selecting one of the higher pump speed settings for the Spa mode, but after reading the on line manuals I'm now not sure it will, any thoughts or anyone done a similar install? or any other simple way around this?
Because the house is a vacation rental I want the controls simple, don't want the guests adjusting any settings.

All thoughts and other options welcome.

 

[jblizzle]

Why not just install a simple 2-speed motor on your existing pump?
Then you could leave it running on low speed on the timer and just have the renters, flip the switch to high speed when they are turning the valves for the spa. Or wait, what do you mean the spa is on a timer?

The VS pump electronics are susceptible to nearby lightning strikes, so adding a surge protector is highly recommended in your area.
You should not need an external timer with the VS pumps at all.

 

[Gary.B]

I know the 2 speed motor would be cheapest option, but like the savings form the variable speed and also the lower noise as the pump is located right outside the master bedroom window.

The current system as I understand it powers the pump from the Intermatic timer when in pool mode, to turn the Spa on you just turn a hard wired mechanical timer which I assume triggers a relay in the Intermatic which then switches over the jandy valves, sucking water from the spa drain and returning to the spa jets.
When the pool is off and the spa timer is turned the pump starts up valves switch over as before.

If I do away with the current setup and use the pump timer, how can I get the variable speed pump to start up when the spa is requested? and how can I get the pump to change speed and the valves switch over when the spa is requested when the pump is already running in pool mode?

Yes, surge protector is a good idea.

 

[jblizzle]

A 2-speed on low is virtually silent. And the savings of a VS pump is not very significant over a 2-speed running on low, unless your electricity is pretty expensive.

Interesting the way it is setup now ... almost the way hotels are setup with just a timer for the spa. I have a feeling this is not going to be trivial to wire in a VS pump into that system. I can not think of an easy way for the spa timer to change the pump speed ... you might need some kind of automation system that can communicate with the pump, and that is going to make the control a little different. Instead of the mechanical spa timer, they could just push a button for the spa which would then be able to set valves, pump speeds and have a digital countdown timer (I think). In any case, it is going to get expensive with a VS pump and surge protection and an automation controller.

Going back to my first thought, a 2-speed might be pretty easy wire into the existing system where the mechanical spa timer could just trigger high speed and the Intermatic pool timer would just trigger low speed. Although skimming and cleaning would be reduced in low speed, and at times there is going to be a desire to have the pump on high while in pool mode.

Kind of hard to think it through without a good understanding of the existing setup.

 

[JasonLion]

The IntelliComm 2 should be able to handle this without any problems. This is exactly the kind of situation it is setup to handle.

On the other hand, I also think you would be better off with a two speed pump. The small additional electrical savings of the variable speed won't pay back the much higher uf front costs of the variable.

On the third hand, controlling the two speed will require a SPDT relay to make sure high speed and low speed aren't both energized at the same time, which adds a little complexity to that approach.

 

[Gary.B]

Thanks for the input JB and Jason, your probably right on the face of it the 2 speed would look to be a good alternative, however given that it looks as though the Intellicomm 2 will do the interface as I'd first hoped, I'm probably going to go with the VS. (I've got a month to decide before I travel out, but need to plan and order any parts prior to that)

As you said JB , I should have explained in more detail my set up and what I needed / was hoping to achieve which probably would have put a slightly different perspective on things.

Apart from wanting to reduce my overall pump running costs and reducing pump noise, with it being a Vacation rental as well as my own home there are certain things I need to achieve:

As the heater runs pretty much constantly for 6 months of the year over winter I need an optimum pump speed to satisfy that demand; need an optimum speed for when the Spa is called for which can be anything from 1+hrs per day (historically) all year round; need a speed for vacuuming / filtering / skimming ( currently don't have a robot); for the summer months when the heater isn't called for then need another optimum speed for just circulating the water 10-12 hrs per day and finally will potentially have to have a scheduled in speed for when the water features are running ie. deck streamers / fan sprays and maybe in the future a slide with water flush- such as the Interfab G force.

Any advise or experience of what flow rates/ pump speeds I should be aiming for, for each of the above?

Also I'm going to need a flow meter of some description to optimise settings, any preferences, best makes etc? ( I do have a Jandy check valve I could easily upgrade with a Flowvis)

 

[JasonLion]

The ideal pump speed needs to be figured out empirically for each pool. It depends on way too many different factors to predict.

There is no real reason to get a flow meter. GPM is almost never the criteria you are optimizing, so not very helpful to know.

10-12 hours a day is way too much total pump run time. Most pools are fine with four hours a day, some need a little more, but nothing like that much.

 

[jblizzle]

While the flow meter is not needed as Jason said, if you decide to get one, go with the Flo-Vis.

 

[Gary.B]

I thought the speeds would be pool specific- pump and plumbing loses etc, but thought I had read some where that you should be looking for certain GPM rates to complete specific tasks? If not GPM, what is the criteria, pressure?

The pool is set up currently for 8am to 5-6pm now and the 8am to 6-8pm summer, it was like that when I bought the place and the pool guy said that's what it needs to be, didn't know any better to start with but the more I've read / researched, the more I'd agree both settings to be excessive!

 

[JasonLion]

For general circulation you want the lowest speed where the skimmers work effectively, but not below 1000 RPM. For heaters you want a little above the lowest speed where the heater doesn't give a low flow error. For vacuuming usually any medium high speed will do, but some people like to fine tune it. And so on.