Monday, December 28, 2009

Pool guys wash hands after using the restroom

We had some people over for the holidays and after they left, my wife went to tidy up our guest bathroom. Before they arrived, she had put a  new carefully folded Christmas towel on the rack. Although all of our guests used the bathroom at some point in the evening (some more than once), she discovered that neither that towel nor others on the washstand had been touched.

None of our guests had washed their hands!

Failure to wash one’s hands is not all that uncommon among the general population. I see many men leave public restrooms at movie theatres, airports, and sports arenas without first washing their hands.  It is such a common site that I generally don’t think much about it.

An unusual observation

Last year while attending the Western Pool and Spa show, I noticed something strange. Every single pool man that I saw in the restroom, over the course of the three day event, washed their hands before leaving.

Why would these pool men wash their hands 100% of the time, while in the general population, the rate is much less?

Then I recalled my CPO (Certified Pool Operator) training, and I began to reflect on how unique a pool guy’s expertise is. Pool guys know about both sanitization and filtration, and both of these are key.

Sanitization

In the CPO course we learned that E. coli is a strain of bacteria that lives naturally and harmlessly in the lower intestines of  healthy humans.  Problems arise, however, if E. coli gets ingested. Then, it is out of place in the entrance to our digestive system and causes problems such as diarrhea, nausea, and stomach cramps.

Now, some people might think that a well placed piece of toilet paper will keep the E. coli that is in human waste from contaminating one’s fingers. If their hands look clean they may figure they don’t need to wash them. But, to see why this logic is flawed,  let’s look at another area of pool guy expertise.

Filtration

E. coli is a bacteria that is about 1 micron in diameter; this is incredibly tiny.  It is so small that it can pass through even the finest DE pool filter that can only filter down to about 4 microns. It will also easily pass through a paper pool cartridge filter that can only filter to about 15 microns. Now, let us assume that toilet paper can filter as well as a paper cartridge filter (even though it probably is not this good). To a 1 micron E. coli bacteria, a 15 micron filter looks as wide open as an open garage door looks to a human. The bacteria just goes right through. I wonder if most doctors and nurses trained in sanitization, but in not filtration, even think about this.

The pool guy’s unique expertise

The pool guy’s unique combination of knowledge of sanitization combined with knowledge of filtration probably explains why all the pool guys at the convention washed their hands after using the restroom. As pool guys, we need to share our unique expertise with a wider audience. Public health depends upon it.  

Here’s to a healthier 2010!

Wednesday, December 9, 2009

Case study: Variable speed on Jandy RS

Yesterday I had a chance to install a variable speed pump on a pool that is controlled by a Jandy RS system. Now, this was an older system that uses the 52 pin board and was, therefore, not compatible with Jandy’s variable speed pump. While some of Jandy’s e-pumps come with an upgrade chip for the RS control system, the chip will not fit in a 52 pin board – it only fits in boards made within the last year or two. Thus, if I were to use Jandy’s e-pump, I would have to upgrade the board. This was too expensive.

Instead, I chose to use a Pentair Intelliflo VS3050. This is the pump that used to be called the Intelliflo 4 x 160. The VS in the name indicates Variable Speed (as opposed to their other pump that is variable flow). The 4 stood for 4 speeds and the 160 stood for the max gpm.

To use the VS3050 with the Jandy RS system I had to used Intellicom II. This is a major advance over the first generation Intellicom. This is a small cell phone size adapter that converts the 24 v relay outputs of the Jandy system to RS485 communication protocol that selects the pump speed.

The Pentair reps will tell you that the Intellicom requires the use of a separate auxiliary per speed. This isn’t quite true, and if you did it that way, it would be complicated for the customer to use.

Here is how I setup my install. I set the following speeds on the pump. (I set the speeds before connecting the controller):

Speed 1: I set this to a speed fast enough to operate the suction pool vacuum.  Pressing the “Filter Pump” button on the Jandy activates this speed.

Speed 2: A super low speed for filtration, This is just fast enough to break the plane of the water with the skimmer wier. The “Low Speed” button on the Jandy activates this speed. (Turn on dip switch 2 to set “Aux 2” to “Low Speed.”) This is the only extra auxiliary that is necessary to use that is not used with a single speed pump.

Speed 3: A speed suited for the 400,000 BTU heater --somewhere close to 40 gpm. This is higher than the low speed setting. Imagine what would happen if the heater was turned on when the “Low Speed” was selected. The pressure switch would be marginal and the heater would not have the minimum flow that the heater required. To avoid this, I used the “Electric Heater” relay output on the top of the Jandy board near the actuator outputs to activate Speed 3. The Logic of the Intellicom is such that it always selects the higher of the speed number if more than one is selected. In other words, if both speed 2 (low speed) and speed 3 (heater speed) are selected, it will run at speed 3.  This protects the heater. It is also fool proof. The customer can’t select the wrong speed.

Speed 4: This is a high speed for the spa jets. It is really cool how I activate this speed. I used the “spare aux” relay output located on the back of the RS control board. To get this relay output to activate when the spa is turned on, set dip switch 6 to “on". This way, any time the spa is switched on, the pump automatically goes to speed 4. The customer doesn’t have to do anything different. They just press the spa button as usual and the jets come on high.

Two good things about this installation:

  1. First is saves energy. The customer should save around $900 per year.
  2. Second, it is no more complicated for the customer than would be a two-speed pump. While the pump itself has more speeds and is more adjustable, all the complexity is kept in the background. It is very simple for the user.