Chemtrol Pool Controller: Difference between revisions

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=== Flow Meter ===
=== Flow Meter ===


The flow meter validates the presence of fresh sampled water as an input to the Chemtrol unit.  The flow meter is a [https://www.gemssensors.com/search-products/product-details/rfo-type-electronic-flow-sensor-155481 Gems RFO-Type 155481], as installed during a service call by Aquatic Source in August 2016.
The flow meter validates the presence of fresh sampled water in the "bypass line" for monitoring by the Chemtrol unit.  The flow meter is a [https://www.gemssensors.com/search-products/product-details/rfo-type-electronic-flow-sensor-155481 Gems RFO-Type 155481].  This particular model is what was installed during a service call by Aquatic Source in August 2016.  It was subsequently replaced with an identical model in April 2021.  The failure seems very premature; the unit no longer produces pulses on its output.  An initial tear-down/diagnosis shows no obvious root cause.


There is a slight discrepancy to work out with this flow meter - the 1/2" model has a standard flow range of 4 to 20 GPM, per the catalog pageThe Chemtrol typically shows about 1 GPM during operation with this sensor.
The flow meter is an absolute necessity for automated chemical control.  Due to the large main re-circulation lines in the system (larger than 2 inches), a bypass line is used to provide an alternate path to the pH and ORP sensors.  The flow meter verifies that sufficient flow is present in this bypass line (such that the measurements reflect the chemical levels in the main re-circulation line and pool). 
 
The flow meter for the bypass line can be disabled under certain circumstances.  However, this must be used with extreme caution, as operating a chemical feed without sufficient monitoring could cause dangerous/damaging chemical reactions.
 
Upon installing the newest unit (April 2021), the bypass flow rate read-out was adjusted.  Per the datasheet for the 155481, the unit produces 225 Hz (pulses/second) for a 20 GPM flow rate.  The Chemtrol requires a value in "pulses per unit volume".  In this case, 225 Hz / 20 GPM = 11.25 Hz/GPM, or 11.25Prior to April 2021, a default value of 1 was used, resulting in a typical (incorrect) readout of 0 to 1 GPM.


The wiring for the flow meter is shown in the "PC2100 Auxiliary" (page 43), as part of the [[Pool_Systems_Automation#Auxiliary|Pool Systems Automation Drawings - Auxiliary]] package.
The wiring for the flow meter is shown in the "PC2100 Auxiliary" (page 43), as part of the [[Pool_Systems_Automation#Auxiliary|Pool Systems Automation Drawings - Auxiliary]] package.

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