Running 2 pumps vs varible speed pump

[smeestu]

Just thinking aloud really thought i would throw it out there see what people think .My pool is about 15 months old now and all is well happy with the trouble free method havent drianed down ,no green water etc .So now my pool gets a lot more use than i originally expected when i bought the pump/filter etc mainly due to the fact that we sort of opened it to the local kids so they could enjoy it ( we live out in the sticks in Thailand).i have a 1.5 hp Emaux pump that works fine with a Emaux 45g p/hr swg backed up with Liquid chlorine .If i run the swg 24/7 i get some pretty bad electric bills so was wondering if i bought say a 1/2 hp pump plumbed it next to the 1 1/2 pump with some no return valves on the outlets wpuld this be a viable idea to run say the main pump 8-10 hours a day then switch to the smaller pump (on timers) to run the rest of the 14-16 hours which would save a fair bit of money in the long run but produce a lot more chlorine .It is a cheaper option than replacing my pump with a variable speed one they start at about $900 US any thoughts ?

 

[Patrick_B]

Hey smeestu, good to see you again!

Did you oversize the SWG? I can't recall, but doing that and/or having just one dual speed pump might be a better option for you in this case. I do remember it's hard, or a long way to get bleach, but more supplementing with it could be helpful as well.

 

[pooldv]

I run my Pentair 3hp VS pump at 1100rpm for skimming and making chlorine, it only draws 150 watts at 1100rpm. Pentax has a new 1-1/2hp VS pump, 342001, that might be a cheaper option. It is $659 at sunplay.com.

 

[smeestu]

Thanks for the replies internet has been down so im a bit late back on here . The biggest swg i could get without a massive price hike was 45g p/h which was rated at 120,000 l tropical my pool is 93,000 but running it at 8 hours a day still seems to struggle even on days of no swimmers. it should make 360g of chlorine in that time which should be enough with little or no load .Im in the process of raising my CYA up 50 to 70 as advised on here but there is no CYA locally so im having to do it with some trichlor i had left over . when its busy i top up with Liquid chlorine which as you remember correctly is nearly a 200 mile round trip to pick up then theres the heat here and storage with it going "off" .Its more about the econmics of it all really im on a tight budget, is there any way that you can safely without damaging the pump "turn it down" ie lower the rpm i was looking at 1/2 hp pumps i could pick one up for about $160 US which is obviously a lot cheaper than swapping my pump for a variable speed one which would obviously be the best answer if i had the spare $900

 

[smeestu]

Hope its ok to post links but it looks like you can add one of these to a standard pump and turn it into a variable speed pump GS1 (120 / 230 VAC V/Hz Control) | AutomationDirect.com anyone tried this ? . Picked it up off a electrical engineering site ac - Controlling water pump speed - Electrical Engineering Stack Exchange and also here 2HP 1 5KW VFD Drive Inverter 220 250V Control AVR Technique Brand New Great | eBay could save people a lot of money if they are happy with there existing pumps but would like to run there SWGs longer . Any electrical engineers out there

 

[sargent]

I would not use one of those GS1 units. They are meant for 3 phase output, and my guess is that you have a single phase motor. Do you have any water features, like a spa or waterfall? If it is just a simple pool, then you don't need a 1-1/2 hp motor. What you could do is get a two speed motor and run it on low. Assuming you don't need 1-1/2 hp, I would suggest you get a 1 hp two speed motor and replace the impeller on your pump with one meant for a 1 hp motor.

 

[smeestu]

Thank for the input I have been reading some conflicting reviews on these GS1 units and am not convinced either now there seems to be a few that are adapted from 3 phase to work on single but then there is not too much savings in real world use of them o well back to the drawing board . Just trying to see if there was a cheaper option to buying a new pump as i need to run the SWG longer to keep up with my chlorine demand but the water is clear and as i said before im on a budget

 

[n240sxguy]

I used to sell industrial electrical parts up until about 5 years ago. At the time there wasn't a single phase variable speed drive available that I knew of. There was one that I sold, but it converted the output to a simulated 3 phase to the motor. Maybe there is now. The problem I see with it, as I assume it works the same way the 3 phase ones work, is the motor windings have to be inverter rated. i.e much higher voltage ratings. As far as I know, pool pump motors are not, so it would drastically decrease its life with the voltage spikes that the drive produces while manipulating the frequency of the electricity and speed that the motor runs at.

 

[n240sxguy]

Also, a 2 speed motor can be had for just under double what that GS1 sells for, and it's guaranteed to work correctly.

 

[smeestu]

Thanks for your input i think ill have to save up again and change the pump out then to get the maxium use out of the SWG at a reasonable cost so keep ill topping up with 10% liquid chlorine for now one side effect of running the SWG a lot was that the PH was rock solid at 7.6-7.7 for 2 or more months with just the SWG running but when i add Liquid chlorine i have to bring it back down evey 1 1/2 to 2 weeks no big problem though .

 

[cowboycasey]

You could get one of these

this little guy is .5hp and 2 amps running JA50
LX JA50 0.5HP/0.37KW Whirlpool SPA Circulation Pump LX Whirlpool Bath Pump Model JA 50-in Centrifugal Pumps from Industry Business on Aliexpress.com | Alibaba Group

this is a 2 speed 1.5hp 3 amps on low and 8 amps on high for under 400 WUA200-II
LX WUA200 II SPA Pool 2 Speed Pump 60Hz for US CANADA spa-in Centrifugal Pumps from Industry Business on Aliexpress.com | Alibaba Group

you could probably have 1 by the end of the week...