Backwashing - Revision history

Matt Parnell: /* Start Normal Operation */

2021-09-05T13:51:17Z

Start Normal Operation

← Older revision		Revision as of 13:51, 5 September 2021
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	# Start the [[Pool Main Pump Motor\|main pump motor]] by pressing the <b>Start</b> button on the motor starter.		# Start the [[Pool Main Pump Motor\|main pump motor]] by pressing the <b>Start</b> button on the motor starter.
			# Return the temperature controller setpoint to the nominal value (i.e. 82 °F) if adjusted earlier.
			# Bleed air from the filter tanks after several minutes of operation.
			# Adjust the output flow of the pump to be within 600 to 650 GPM. The flow rate must exceed the required minimum (570 GPM with some margin) but not grossly exceed the combined maximum flow rate of the sand filters (560 GPM). Note that 560 GPM is not a typo; refer to [[Sand Filters]] for discussion on this discrepancy.

Matt Parnell: /* Procedure */

2021-09-05T13:48:17Z

Procedure

@@ Line 41: / Line 41: @@
 # Verify flow is present at the outflow pipe on the north side of the pump house.
 # Operate until the water flows clear or 10 minutes has elapsed, which ever occurs first.  An excessively long backwash is not recommended as it may result in flushing filter sand into the sanitary sewer.
 The [[Pool Systems Automation#Stack Light|stack light]] indicator should flash an alternating red-green pattern while backwash is active.
 Do not turn on pool fill during backwash.  It is desired to send as much pool water (versus fresh/city water) to the sanitary sewer as possible.

Matt Parnell: /* Set Valves to Backwash */

2021-09-05T13:45:51Z

Set Valves to Backwash

← Older revision		Revision as of 13:45, 5 September 2021
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	=== Set Valves to Backwash ===		=== Set Valves to Backwash ===

			The pump must be stopped prior to adjusting the valve positions.

	# Open Valve #1		# Open Valve #1

Matt Parnell: /* Set Valves to Backwash */

2021-09-05T13:38:28Z

Set Valves to Backwash

← Older revision		Revision as of 13:38, 5 September 2021
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	# Open Valve #3		# Open Valve #3
	# Close Valve #4		# Close Valve #4

			A valve is open when the lever arm is parallel (in line) with the pipe. A valve is closed when the lever arm is perpendicular (turned 90 degrees with respect to) the pipe.

	NOTE: Improved marking and documentation of these valves and positions to follow.		NOTE: Improved marking and documentation of these valves and positions to follow.

Matt Parnell: /* Procedure */

2021-09-05T13:37:37Z

Procedure

← Older revision		Revision as of 13:37, 5 September 2021
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	# Disable the call for heat by lowering the temperature setpoint on the temperature controller to a value several degrees below the sensed temperature (in the future, a switch may be added to do this).		# Disable the call for heat by lowering the temperature setpoint on the temperature controller to a value several degrees below the sensed temperature (in the future, a switch may be added to do this).
	# If the boiler was operating in Step #1, wait for the boiler circulation pump to stop. This may take several minutes. Observe that during this period, the manifold temperature will drop, approaching the boiler inlet (sensed) temperature. <b>It is important to allow the boiler to complete a proper cool-down prior to cutting water circulation. Failure to do so could result in an over-temperature trip, or damage to the boiler itself.</b>		# If the boiler was operating in Step #1, wait for the boiler circulation pump to stop. This may take several minutes. Observe that during this period, the manifold temperature will drop, approaching the boiler inlet (sensed) temperature. <b>It is important to allow the boiler to complete a proper cool-down prior to cutting water circulation. Failure to do so could result in an over-temperature trip, or damage to the boiler itself.</b>
	# Stop the main pump motor~~. Switching off~~ the ~~disconnect (the lever~~ on ~~the enclosure above~~ the motor starter~~) may be necessary in some cases (see below)~~.		# Stop the [[Pool Main Pump Motor\|main pump motor]] by pressing the <b>Stop</b> button on the motor starter.

	NOTE: These steps are identical to the first three followed when [[Cleaning the Strainer Basket#Preparation\|cleaning the strainer basket]].		NOTE: These steps are nearly identical to the first three followed when [[Cleaning the Strainer Basket#Preparation\|cleaning the strainer basket]].

	=== Set ~~Valve Positions~~ ===		=== Set Valves to Backwash ===

	# Open Valve #1		# Open Valve #1
Line 29:		Line 29:
	# Open Valve #3		# Open Valve #3
	# Close Valve #4		# Close Valve #4

			NOTE: Improved marking and documentation of these valves and positions to follow.

			=== Backwash ===

			# Start the [[Pool Main Pump Motor\|main pump motor]] by pressing the <b>Start</b> button on the motor starter.
			# Verify flow is present at the outflow pipe on the north side of the pump house.
			# Operate until the water flows clear or 10 minutes has elapsed, which ever occurs first. An excessively long backwash is not recommended as it may result in flushing filter sand into the sanitary sewer.

			The [[Pool Systems Automation#Stack Light\|stack light]] indicator should flash an alternating red-green pattern while backwash is active.

			Do not turn on pool fill during backwash. It is desired to send as much pool water (versus fresh/city water) to the sanitary sewer as possible.

Matt Parnell: /* Process */

2021-09-05T12:58:54Z

Process

@@ Line 13: / Line 13: @@
 Backwashing also dumps a tremendous amount of water into the sanitary sewer, often leading to a necessary fill post-backwash.  Reducing the frequency of backwashing (to only when it's deemed necessary versus on a too-frequent interval) conserves water and can improve overall water clarity.
-== Process ==
+== Procedure ==
-The process for backwashing is as follows:
+=== Preparation ===

Matt Parnell at 18:37, 2 September 2021

2021-09-02T18:37:41Z

← Older revision		Revision as of 18:37, 2 September 2021
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	Backwashing is the process of reversing water flow in ~~a filter~~, flushing trapped particles and material (debris) to waste (sanitary sewer).		Backwashing is the process of reversing water flow in the [[Sand Filters\|sand filters]], flushing trapped particles and material (debris) to waste (sanitary sewer).

	== When to Backwash ==		== When to Backwash ==

Matt Parnell: /* When to Backwash */

2021-06-04T23:57:21Z

When to Backwash

← Older revision		Revision as of 23:57, 4 June 2021
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	Per PHTA guidance, backwashing the sand filters is necessary when the gauge pressure increases 8 to 10 PSI above the starting pressure (typically about 9 to 10 PSI).		Per PHTA guidance, backwashing the sand filters is necessary when the gauge pressure increases 8 to 10 PSI above the starting pressure (typically about 9 to 10 PSI).

			In other words, when the tank gauge shows 17 to 20 PSI, backwashing is necessary. That said, depending on other parameters (such as flow rate), backwashing before this threshold may be necessary. To maintain proper filtration, the system must have sufficient flow to fully turn over every 6 hours (4 times daily).

	== Excessive Backwashing ==		== Excessive Backwashing ==

Matt Parnell: Created page with "Backwashing is the process of reversing water flow in a filter, flushing trapped particles and material (debris) to waste (sanitary sewer). == When to Backwash == Per PHTA g..."

2021-06-04T20:55:48Z

Created page with "Backwashing is the process of reversing water flow in a filter, flushing trapped particles and material (debris) to waste (sanitary sewer). == When to Backwash == Per PHTA g..."

New page

Backwashing is the process of reversing water flow in a filter, flushing trapped particles and material (debris) to waste (sanitary sewer).

== When to Backwash ==

Per PHTA guidance, backwashing the sand filters is necessary when the gauge pressure increases 8 to 10 PSI above the starting pressure (typically about 9 to 10 PSI).

== Excessive Backwashing ==

Excessive backwashing will result in an inability to remove smaller particles. Sand filters are most effective at trapping small particles when they are at the latter (higher pressure) part of the cycle. Therefore, premature backwashing may result in lower water clarity.

Backwashing also dumps a tremendous amount of water into the sanitary sewer, often leading to a necessary fill post-backwash. Reducing the frequency of backwashing (to only when it's deemed necessary versus on a too-frequent interval) conserves water and can improve overall water clarity.

== Process ==

The process for backwashing is as follows: