Real cost for SWG use

[waterbear]

Warning newbie SWG questions here. What do the actual cells run on? 120vac I assume, what are they rated for UL wise 2 amps, 5 amps? How do they know if water is being passed through the cell? Is the cell powered from the same circuit as the pump? I mean if the pump is on a timer does the cell need to be on the same timer or do they somehow know when it's on or not? To me the selling point might be the fact the pool can sit at .5 free all by itself.

Mine is hardwared into the house wiring and it is plumed with a flow switch so it will not run if the pump is not on. Moot point on mine since I have the Aqualogic which also controls my pumps, lights, heater, water features, etc.
The electrician who my builder subcontracted pulled a new circuit for all my pool stuff.

[Mark_WATERMAID]

Hi Brock

The cells run on relatively low voltage DC. You will find that the life of the cell is directly related to the applied voltage. The higher the voltage, the lower the cell life. In fact if you push the voltage over 11.4 volts, the electrodes become jump electrodes and although the cell will produce more chlorine, you are sacrificing cell life to get it. The amperage that you ask about is not nearly as critical as the voltage. In fact you can push the amperage quite high as long as you don’t exceed critical voltages.

As far as pumps and chlorinators go, all chlorinators are wired with the pump so that when the pump is on the chlorinator is powered. Pump off, chlorinator off. Some units use mechanical flow switches with springs and some use electronic switches with no moving parts to shut down the system when flow stops

Mark Manning
President
Watermaid Canada
www.watermaid.ca
mark@watermaid.ca

[Mark_WATERMAID]

I can speak for Watermaid but don’t have numbers for the rest of the units out there. I don’t suppose that it will be much different for the rest of them. The total cost to run a Watermaid unit for a season is between $70.00 and $80.00 maximum. This includes chemicals and electricity and assumes that the unit is run at 100 % 24 hours a day for the entire time. One note for everyone, I am in Canada so our pools are seasonal here. This is the cost to run a full 5 months. To compare, the average cost to run a pool on regular chemicals in Canada is $400.00 per year.

Mark Manning
President
Watermaid Canada
www.watermaid.ca
mark@watermaid.c

[PatL34]

I did do a check of the running costs a few years back, but did not keep a record of the calculation, so here goes for another try.

Monthly Electric Cost
--------------------
240 volt 2 phase supply at 1.0 amp = 240 watts. This is the value of the supply to the transformer in the DG220 Control Unit only.

So 240 X 12 hours/day = 2880 watthours X 365/12/1000 = 87600 watthours = 8.76Kwh per month X $0.1/Kwh (per OUC rates rounded) = $8.76/month

Monthly Cell Wear Cost
----------------------
Assume $550 replacement cost, 5 year life, 12 hours/day for 365 days.

550/5 years/12 months/2(1/2 day) = $4.6

Monthly Muriatic Acid Cost
-------------------------
2 gallons @ $3.67 = $7.34

Total Monthly Cost = 8.76 + 4.6 + 7.34 = $20.7

(Corrected values applied in this post)

Any upsets and extra chemicals like baking soda, Borax, and incidental bleach are not included.

Hope this helps, and if there any questions, please let me know.

Pat

[KurtV]

Pat,
Thanks for the info. One minor quibble; the average residential electricty cost in the U.S. in 2003 was 8+ cents per kilowatt hour.

http://www.eia.doe.gov/cneaf/electri.../table5_3.html

[Brock]

Yup, actually I would bet it is closer to $.10 now. On the other hand did you actually take a reading off the power supply for the unit or was that just what it was rated for? 24w does seem reasonable for what it is doing though.

At 8.76 kw per month at $.10 is still $.876 a month so you have the cost correct, maybe slipped a decimal?

[PatL34]

I went and did a further measurement to check my original figures, and did in fact read my amp meter incorrectly.

The electric cost should be 1 X 240 = 240 watts x 12 hours daily running time = 2880 watthours X 365/12/1000 = 8.760Kwh X $0.1/Kwh = $8.76

Total cost = 8.76 + 4.6 + 7.5 = $20.86

This seems to compare with what I calculated previously 2 years ago.

Sorry about the error.

Pat