Dissolved Air Flotation System
Installation, Operation & Maintenance Manual
DAF Theory of Operation
General Operational Guidelines
General information on the installation of hydro-flo
Technologies equipment can be found in the following document.
• General IO&M
to all Hydro-Flo
Please review that information before the following
information specifically geared toward the installation operation
and maintenance of
The DAF is supplied with an adjustable
effluent weir. For most applications, the typical and maximum flow
rates fall well within a common range so as to allow a single,
median weir setting for all conditions.
The weir, upon initial startup, should
be set so that, at max flow, water comes to within approx 1/2" of
overflowing the float beach area.
Depending on your application, the type
of "float" that accumulates on the surface of the flotation cell can
be relatively thin or thick. The level of the floatation cell can
be either increased or decreased (by raising or lowering the
effluent weir) to allow for the most efficient skimming of either
thin or thick sludge blankets.
Just remember not to set too high so as
to create an overflow condition in the DAF unit scum chamber.
The weir height is not set too low so
as to prohibit the flight skimmer from coming in contact with the
water level in the separation chamber and properly removing the
The weir is set as close to dead level
to achieve completely even depth of water (durring operation) over
the entire weir length. This will ensure that the flow through the
DAF is evenly distributed across the DAF width.
In addition to the standard plumbing
data found in the general IO&M data, you will need to give
consideration to the following DAF specific connections
The recycle plumbing must be the
same size as the injection nozzle connection size on the
equipment. Do not reduce the size of the recycle piping as this
might cause inappropriate velocities before it enters the unit.
It is very important to locate the
pressure relief valve as close to the DAF influent "T"
assembly. The farther away from the "T" the valve is located,
the greater the chance that bubbles will coalesce in the
plumbing between the valve and the DAF influent and cause bursts
of bubbles in the separation chamber disturbing the accumulated
float and also reducing the efficiency of the overall DAF
The recycle pump suction plumping
must be the same size as the DAF unit recycle effluent
connection. Reducing the size of the plumbing may reduce the
performance of the recycle system. Also, try to run the recycle
pump suction piping as short a distance as possible, through as
few changes of direction as possible.
In some cases, the recycle system
re-circulation plumbing does not have a connection fitting on
the DAF unit. For these units, the re-circulation plumbing is
run over the top of the DAF unit and discharged into the
effluent chamber. The re-circulation plumping must be the same
size or larger than the recycle system connection. Reducing the
size of the plumbing would reduce the range of adjustment for
the re-circulation valve. Also, as always, try to run the
piping as short a distance as possible, through as few changes
of direction as possible.
Hydro-Flo Technologies, Inc. DAF systems
are designed to remove non-settling (either floating or stagnant)
suspended solids as well as FO&G from potable water, process water
and wastewater streams. The microscopic air bubbles created when
the dissolved air releases are very effective at lifting even heavy
particles to the surface where they exit the waste stream and are
skimmed off for further processing.
The Recycle / Air Dissolving (RAD)
System is designed to recycle a portion of the DAF effluent flow
into a specially designed pressure vessel where the air/water
interface and gas mass transfer occur. The water becomes highly
saturated with air under pressure before it is injected into the
influent waste stream of the DAF unit.
For detailed information on clarifier
design and theory of operation, please refer to our "DAF design
As stated above, a DAF's soul purpose in
life is to remove non-settling (either floating or stagnant) solids
from potable water, process water and wastewater streams. This
being the case, an operators main focus will be on the effective
management and removal of the accumulated sludge in the DAF's
skimmed float chamber and sludge collection hopper.
The RAD system is what separates the
DAF unit from a typical API type Oil/Water Separator. The RAD
system is used to create water that is saturated with dissolved air
and introduces this air/water mixture into the DAF
flotation/separation chamber at the influent point. Once in the
separation chamber, the dissolved air begins to come out of solution
and create small air bubbles that attach to the particles (oil
droplets, solids, etc.) in the waste steam. Once attached the air
bubble and the particle rise to the surface of the separation
chamber where is skimmed off of the surface by the flight skimmer
and thus removed from the waste stream.
The standard RAD system consists of the
following main components:
RAD Tube or Vessel
Air Pressure Switch
Air Pressure Regulator
Air Line Ball Check and Needle
2-Way Solenoid Valve with Manual
Pressure Relief Valve
Swing Check Valve (Recycle Pump
Sight Glass with Two-Point Level
Two (2) Diaphragm Valves; One (1)
Recycle By-Pass and One (1) Recycle Injection
Please check your General Arrangement
Drawings for the proper location of these devices for your system
and verify that they are present.
Three conditions must be met before
the RAD System will operate in automatic mode and energize the
solenoid to deliver air to the pressurization tank. They are:
The Air Pressure Switch (if
provided on the air supply line) must detect sufficient
pressure (typically 95 psi OR 10 psi above desired pump
The recycle pump must be
The high level sensor (LSH)
must indicate the need for air.
When all of these conditions are
met, the system will operate in automatic mode.
EQUALIZING THE RAD SYSTEM
Before operating the DAF, the RAD
System must be equalized. In order to equalize the RAD system,
follow these steps:
ENSURE that there is sufficient
clean water in the DAF effluent chamber to fill the
pressurization vessel and all of the associated piping.
ENSURE that the air supply
pressure exceeds 90 psi OR the airline pressure switch set
SET the pressure regulator for
~ 60 psi OR the desired pump curve backpressure.
CLOSE the Recycle Injection
CLOSE the Recycle By-Pass
CLOSE the RAD effluent ball
OPEN the isolation valves on
the sight glass.
OPEN the Recycle Pump isolation
Turn the Recycle Pump ON until
the water level in the pressurization vessel is high enough
to activate the High Level Sensor in the sight glass. Once
the level at this point is achieved, turn the recycle pump
OPEN the manual air inlet
by-pass valve and start to introduce pressurized air into
the system. Continue to let air into the system until a
pressure of ~ 60 psi is reached on the sight glass pressure
gauge. Once this pressure is reached, turn off the air
inlet by-pass valve.
During this operation, watch the
pressure in the pressurization tank as well as the pressure
regulator. The regulator may need to be adjusted as the
Once the proper water level and air
pressure are achieved, let the system sit for approximately 30
minutes in order for the air to completely saturate the water.
Introduce more air if the pressure drops below the desired set
DAF (Dissolved Air Flotation) system creates microscopic air
bubbles that are attached to incoming wastewater particles in
order to float them. Once floated, they are separated from the
wastewater and skimmed from the top and into the float scum
chamber. The treated wastewater then exits from near the bottom
of the DAF. The DAF creates it’s air bubbles with a sub-system
called a RAD (Recycle Air Dissolving) system. Proper operation
of the RAD system is key to DAF performance.
The standard configuration RAD
system is designed to take treated effluent from the DAF
effluent end, pump and pressurize it into the RAD pressure
vessel where it is subject to compressed air pressure. The air
pressure then dissolves air into the water to become “saturated
recycle”. Once saturated the recycle is introduced into the DAF
inlet reaction chamber where it co-mingles with raw incoming
wastewater. When the recycle is co-mingled with wastewater the
pressure of the saturated recycle
is released and bubbles form and are enmeshed with the
Operating pressure; 30-80 psi
consumption: 1-5 scfm intermittent.
Flow rate: 10-300 gpm depending on
model. Flow rates are adjustable within the range of the model.
The RAD creates bubbles by
maintaining pressure and an air/water interface in the RAD
pressure vessel (stainless steel vertical vessel pictured above
right). The interface is maintained by a dual level sensor
located in the RAD clear sight tube. When the dual float
sensors are wet, the logic says the level is rising and the air
pressure supply solenoid is energized and air pressure is added
to the RAD vessel. When the dual sensor floats are dry, the
logic says the air pressure is excessive and the air supply
solenoid is de-energized allowing the level to rise. The level
will constantly hunt between (slightly above and below) the two
sensor floats. This is normal.
The level sensors MUST be maintained clean. If allowed to foul
and malfunction the RAD pressure vessel will fill with water and
bubbles will NOT be created. They are easy to remove and clean
while the RAD is operating by closing the isolation valves and
venting pressure with the sight tube drain valve.
The supply air pressure regulator
must be maintained at minimum 10 psi above the RAD pressure. If
the RAD flow rate valves are adjusted the supply air pressure
must be checked to ensure it’s pressure is greater than the RAD
pressure or air pressure will not overcome pump pressure.
Air supply piping also has an air
regulating valve (needle valve) that is used to regulate the
volume or “speed” at which the air enters the RAD system.
Typical setting is combination yellow/green bands. This low
setting will slowly admit air to the RAD vessel to prevent
pushing the RAD level downward too fast.
The RAD system flow rate is
controlled by the RAD flow rate control valve and the flow rate by pass valve. The
rate control valve is used to control bubble quantity and RAD
flow rate into the DAF. The
RAD by-pass valve is used to adjust pressure independently of
the RAD flow rate. This way, RAD flow rate can be adjusted to
achieve the bubble quantity desired and the by-pass valve is
used to adjust pressure which affects bubble size. Generally
speaking, lower pressure ~30 psu produces larger bubbles and
higher pressure ~80 psi produces smaller bubbles. The RAD
system is typically set at 60 psi if started up by Hydro-Flo
Technologies technicians. This is a good starting point.
Remember to adjust air supply
regulator to 10 psi above RAD pressure if the flow rate is
It is recommended that the RAD pump
be allowed to operate continuously in order to maintain the
float blanket in the DAF. If the RAD system is shut down the
float blanket will degrade and floated material may sink and be
flushed out with the effluent during the next startup.
If the RAD system
will not maintain pressure
Check for accumulated grease,
solids buildup in the control valves or RAD pump.
Check for RAD pump wear.
If the RAD system will not maintain
Check for RAD Dual Level Sensor
proper operation. Clean and repair as necessary
Check for RAD air solenoid
Check for available air
Check the air regulator valve
for proper operation. Open fully to blow out debris.
the RAD system will not create bubbles.
Check the RAD water/air
interface level in the RAD clear sight tube. If the tube is
full of water the dual level sensors may have
mal-functioned. Clean and repair as necessary.
Check air supply and air supply
Sludge removal is very important for
the proper operation of your DAF. Draw off the settled sludge
regularly. Do not allow it to accumulate excessively or
operational malfunctions can result.
The sludge, or "float" that is
skimmed into the float chamber should be transferred to a bulk
storage tank as it accumulates. This can be performed as a
manual operation (opening a valve or turning on a pump) or can
be performed automatically via automatic level control systems.
If left unmonitored, sludge may
accumulate to an excessive level. If the heavy sludge (that
accumulates in the bottom of the DAF) level rises to a point
where it will migrate into the separation chamber, suspended
solids may be “washed” out of the clarifier.
Any settled sludge should be drawn
off according to the accumulation rate (this sludge can be
transferred to the same storage tank used for the DAF float, or
another tank depending on your overall process requirements).
The amount and consistency of sludge varies from application to
application. We recommend settled sludge be drawn off
constantly at a rate of approximately 10% of the DAF flow rate.
Monitor the sludge sample ports and adjust your sludge draw off
rate to match the accumulation rate. In a perfect world, the
sludge draw off rate will match the sludge accumulation rate and
the volume of accumulated sludge in the sludge hopper will
always be at the 75% full level. This will allow for maximum
compaction of the accumulated sludge resulting in the highest
solids concentrations possible.
While, in some cases, the DAF can
also be used as a sludge storage device (prior to disposal or
dewatering), more often than not a sludge storage, thickener
tank will be required. The use of an ancillary system for the
storage and conditioning of the accumulated sludge will
typically generate better results than the use of a DAF alone.
If your system was supplied with a
bottom sludge auger/thickener it should be allowed to operate
continuously as it will assist in pre-conditioning or
"thickening" the sludge as well as preventing "rat-holing" in
the sludge chamber.
Please consult your local city and
state regulatory agency regarding specific requirements on the
proper disposal of the sludge generated in your process. If you
need help with the disposal or treatment of the collected
sludge, please contact your local HYDRO-FLO TECHNOLOGIES
On DAF systems that come equipped
with parallel plates, consideration should be given to the
maintenance of the plates. Over time, if left to their own
accord, solids will slowly bond to the plates and reduce the
overall efficiency of the DAF. It is a good idea, as a minimum
to flush the accumulated solids from the plate during the
clarifiers annual internal inspection.
Once the steps for system equalization
are completed, the system is ready for initial start up. In order
to complete initial system start-up, follow these steps:
At this point verify that both the
recycle bypass and recycle injection diaphragm valves are still
Verify that the pressure and level
in the pressurization vessel are adequate. The pressure should
be approximately 60 psi and the level should be such that the
High Level Sensor is activated.
Verify that all control panel
selector switches are in the proper position for automatic
Turn the recycle pump ON.
Slowly OPEN the recycle injection
diaphragm valve until the level begins to slowly drop. Once the
level begins to drop, adjust the valve so that the level in the
pressurization tank stagnates. By matching the pressure in the
RAD vessel to the curve for the recycle pump, you will know your
recycle flow rate. When the water level in the RAD vessel
stagnates, you have matched the designated flow on the pump
curve. Note: Friction loss due to excessive pipe run and
fittings may reduce the actual flow rate into the DAF unit.
Wait for the level in the sight
glass to drop below the Low Level Sensor (LSL). If the level is
dropping too quickly, the needle valve on the air supply can be
adjusted to limit the volume of air that is being introduced
into the RAD Tube. Once this happens, the solenoid should close
and the water level will slowly rise and the process will be
repeated. If the level does not begin to rise, slowly open the
recycle injection diaphragm valve.
The recycle by-pass valve can be
used to adjust the actual flow that is delivered to the influent
of the DAF. Having the recycle valve closed will send 100% if
the flow to the influent of the DAF.
This should conclude the initial start
up of the RAD System. Fine-tuning will be needed in order to find
the correct positioning of the recycle injection diaphragm valve and
the needle valve.
It is recommended that the RAD system
be operated continuously in order to maintain the floating blanket
in the DAF separation chamber. When necessary, in order to properly
shut the system down, follow these steps:
CLOSE the RAD Effluent Ball Valve.
IMMEDIATELY shut down the Recycle
In order to properly re-start the
system after a shutdown, follow these steps:
Turn the Recycle Pump ON.
OPEN the RAD Effluent Ball Valve.
This should conclude the necessary
steps for a re-start as the needle valves and the recycle injection
diaphragm valve have already been set to the proper position in the
initial system start-up steps.
DAF System Startup and Shutdown
Initial Startup or Extended Shutdown – Startup from a dead stop
From a power down state, turn ALL
control panel switches to the OFF position.
Open the control panel and ensure
ALL circuit breakers are in the OFF position.
Power up the panel main voltage
with the door open. CAUTION – live high voltage is exposed.
Use extreme care.
One at a time, turn on the 3 phase
circuit breakers on the top row. Then, one at a time, turn on
all other circuit breakers.
Secure power and close control
Power up again.
Fill the DAF with clean water (if
not already full of process water).
Check the RAD system valves and
sight glass to be sure all connections and valves are in the
full open position.
Ensure there is air pressure to the
RAD system. Set the RAD air pressure regulator to 80 psi (may
be adjusted later).
Open the RAD flow rate control
valve completely (the one nearest the DAF inlet).
Open the RAD by-pass valve
completely (the one leading back to the DAF effluent end).
Turn on the RAD pump and observe
the water level in the RAD sight gauge.
Once water shows in the RAD tube adjust
the combination of RAD flow rate valve and by-pass valve to achieve
50 psi pump pressure (as read on the gauge on the top of the RAD
sight tube). Typical setting for RAD valves is flow rate valve open
~20% and RAD by-pass valve closed.
Observe that the water level in the RAD
sight tube, it should stabilize and hunt slowly to about an inch
above/below the two sensors (a 6-8 inch range). The logic is that
when both sensors are wet, air pressure is applied to the RAD vessel
by energizing the solenoid causing the level to drop. When both
sensors are dry, the air pressure is turned off to the RAD vessel
and the water level slowly rises. If the water level drops too
quickly then regulate air volume with the air regulator needle valve
found on the air piping. Typical setting for that valve is the
second color band from shut. If the water level does not rise then
check pump pressure. Typical setting is air pressure at 10-15 psi
above pump pressure.
Observe in the DAF chamber and
ensure that bubbles are forming in an effervescent way.
Fill the flash/floc mix tanks with
water (if not already full with process water) and start all
Turn on chemical dosing pumps on
HAND one at a time and verify pumps are primed and pumping
properly. Note: Depending on the model chemical dosing pump,
you may have to place each pump in “internal” mode to operate in
HAND. This is done on the pump.
If the system has a polymer day mix
tank inspect the tank contents and replenish as necessary. If
the batch is older than two weeks it may need to be discarded
and replaced. If the polymer is anything other than a
homogenized mix, it is stale.
Place chemical dosing pumps in AUTO
mode on the main control panel. Be sure to return them to
“external” mode when priming is complete.
Verify the pH control system is
working properly – clean and calibrate the pH probe as needed.
Verify the chemical dosing pumps are adjusting pH as indicated
by the pH set point. pH is typically adjusted only in the first
mix tank. Allow the pH to reach the proper level of __________
(8.5 pH typically).
Prepare to manually dose each mix tank
(flash/floc tanks) with chemical. This is needed to get the
chemical at the proper dosage to permit flow thru the system.
Obtain the dose rate from the project chemist or chemical supplier.
The flash tank typically takes coagulant to around 75 ppm. The floc
mix tank typically takes flocculent to 10 ppm.
Once the dose rate is known and the manual dose quantity is
determined, dose BOTH the flash mix and floc mix tanks with
coagulant. Then dose the floc mix tank with flocculent. Obtain
visual confirmation that floc is formed.
Flash #1 mix tank coagulant needed to manually dose the
Flash #2 mix tank coagulant needed to manually dose the
Floc mix tank coagulant needed to manually dose the
Floc mix tank flocculent needed to manually dose the
Observe the floc mix tank. If well
formed floc is observed, then start wastewater flow to the
system. If not, determine the cause and correct before starting
Set the DAF skimmer timer to
accumulate 1-3 inchs of float material. Typical setting 30
seconds on and 15 minutes off.
SHUTDOWN – DEAD STOP – Power Down:
Note, if shutdown period is short term (a few days or less),
simply stop wastewater flow and leave all appropriate switches
in ON or AUTO. The system is in standby. Wastewater flow will
automatically start/stop the chemical dosing pumps with
Stop wastewater flow.
Blowdown bottom sludge if any.
Typically run the sludge pump at 5 – 10 gpm by hand for 2-3 min
or until the water runs clear.
Operate the DAF skimmer
continuously for several minutes to remove all float material
from the DAF. Pump out the float scum chamber and rinse with
water to prevent crusting of material.
Clean and flush the flocculent
dosing pump and day mix tank (if equipped). This polymer will
gel and prevent the pump from operating. If polymer is expected
to remain in the tank for > 2 weeks, the tank must be drained
and cleaned to prevent gelling.
Clean and flush the other chemical
dosing pumps if the chemicals are the type to gel or crust
Turn all control panel switches to
OFF and turn off main power.
Secure air supply to the RAD.
Drain the RAD vessel water and pressure carefully by using the
sight tube drain valve. Remove the level sensors from the top
of the sight tube and carefully clean the level sensors.
Before startup, and periodically you will need to apply liberal
amounts of wheel bearing grease to the surface flight chain and
sprocket assembly. The unit is shipped without grease to prevent
accumulation of road grit during shipping. Use heavy duty workman
gloves with plastic coating to apply grease to entire length of BOTH
The flight skimmer, operated by a
gear-reduced motor and provided with a timer function as standard,
is used to remove the float material from the surface of the
separation chamber and into the float chamber.
The flight skimmer will arrive
accurately adjusted for proper operation. This will include the
proper alignment of the drive and non-drive shafts, sprockets, chain
guide, flight bumpers and chain tension. Any attempt to alter these
settings may require extensive adjustments to ensure proper
Should you have any problem with the
flight skimmer assembly, please contact Hydro-Flo Technologies, Inc.
prior to making any adjustments.
In most applications, the flight
skimmer will NOT need to be run continuously. In fact, running the
flight skimmer continuously can, in some cases, reduce the
efficiency of the system. In order to accommodate this, the unit is
provided with a timer function, typically located on the door of the
control panel, that is activated when the flight skimmer is placed
in the AUTO mode and. The timer will allow the operator to set the
ON and OFF Time for the flight skimmer throughout a wide range of
settings (seconds, minutes, hours).
As a rule of thumb, the flight skimmer
can be run for 3 minutes for every half hour of processing (3
minutes ON, 27 minutes OFF) to provide for adequate float collection
and removal. If you find that you have an unusually large blanket
of floating material when the flight skimmer begins operation after
the OFF time sequence, adjust the timer so the difference between
the On and OFF times are reduced ( 30 minutes ON and 30 minutes
OFF). Conversely, if you find that there is very little floating
material when the flight skimmer begins operation after the OFF time
sequence, adjust the timer so the difference between the On and OFF
times are increased (3 minutes ON and 45 minutes OFF).
The RAD dual level sensors must be
cleaned and maintained regularly in order to ensure their proper
operation. Daily cleaning may be required if the DAF effluent is
dirty and can foul the sensors. Cleaning is easy. Simply close the
RAD sight tube isolation valves, open the sight tube drain valve.
Remove the level sensor from the top using the “cam-lock” fitting.
CAREFULLY remove the sensor. Do not bend the sensor shaft or damage
the floats. Clean as necessary and replace CAREFULLY. Secure the
cam-lock fitting and examine the floats to ensure they are not
touching the sight tube or they may not operate. The sensor tubing
can be CAREFULLY bent near the top of the sensor fitting if needed
to move the floats away from the sight tube walls.
The Air supply regulator has a filter
and moisture separator. The filter should be checked regularly and
the moisture separator should be drained periodically as needed.
If the RAD is subjected to dirty water
regularly then dirt and grease may build up in the RAD flow control
and by-pass valves and in the RAD pump. If your wastewater causes
this then the valves and pump may require periodic cleaning. To
clean the RAD flow and by-pass valves simply open them fully with
the RAD operating. This may be sufficient to blow the accumulated
debris from the valve. The clean the RAD pump may require removal
RECOMMENDED MAINTENANCE SCHEDULE
Check chemical supplies
(if used) and replenish as needed.
Daily if possible.
Check for proper
operation of the sludge auger/thickener (if supplied).
Daily if possible.
Check auger drive shaft
seal. Tighten enough to
eliminate excessive leaking (if supplied).
Weekly if possible.
Drain unit and inspect
interior coatings. Touch up as necessary.
skimmer sprockets and chain need to be washed inspected
and re-lubricated with liberal amounts of wheel bearing
If the unit comes equipped with a
sludge auger/thickener device it will be powered by an electric
motor connected to a gearbox for speed reduction to the auger shaft.
The gearbox is maintenance free and may be mounted in any position.
The auger shaft enters the tank directly adjacent
the auger drive motor. The shaft incorporates a stuffing box type
seal with a compression gasket and two mounting studs with gland
The stuffing box seal will require tightening
of the gland seal nuts to reduce leaking. When you tighten the
gland seal nuts you must tighten them no more than ½ turn each and
check for leaking while the shaft is turning. Never tighten more
than ½ turn without checking for leaking.
When properly adjusted, the gland seal
will drip approximately once every 30 seconds.
NOTE: DO NOT TIGHTEN THE SEAL TO THE
POINT WHERE IT STOPS DRIPPING. Doing so will score the
thickener drive shaft and cause premature shaft failure.
Over time, the stuffing box seal will
reach the end of its adjustment. At this point, you
will be required to install additional packing material.
Typically a Teflon impregnated packing is recommended.
USE EXTREME CAUTION WHEN PERFORMING
This procedure will require four
mechanics to assist and ensure safety. Tools needed include, a
chain breaker, hammer, pliers, tape measure, heavy duty rubber
coated gloves, waterproof grease.
Adjust skimmer chain tension bolts
(2) so the sprocket(s) move toward the middle of the DAF (the
shortest chain length).
Break chain at connector link.
Carefully pull both chains
simultaneously over the drive or non-drive end of skimmer box as
necessary removing skimmer flights (blades) one at a time as you
go. Be careful not to bend or drop flights or chain into the
DAF. Be careful to keep the chain riding on the chain support
angles to prevent
NOTE: You can use the skimmer drive motor to assist but use
extreme caution NOT to get caught in pinch points of the chain
or sprockets. The motor rotation can be reversed by changing
the outside power legs. Employ a certified electrician if not
comfortable or familiar with electricity or electric motors.)
The chain can be pulled or installed from either drive or
non-drive ends of the DAF skimmer box.
Once the existing chain is removed
clean the flights and their pin insertion supports, the
sprockets and the chain support angles.
Adjust skimmer chain tension bolts
(2) so the sprocket(s) move toward the middle of the DAF (the
shortest chain length) if not already done so.
Unroll chains on the floor in the
direction the chain will install into the skimmer box.
Locate the starting end of the
chain. Measure the length of chain to the first skimmer flight
pin on both chains (NOTE: must be the exact dimension on both
chains, flip flop the chain if necessary).
Pull the starting end of the chain
close to the skimmer box and grease the pins.
Install a flight between the two
chains on the pins and place into the skimmer box on the top
chain support angle. NOTE: Be careful to prevent the chain
from falling off the chain support angles.
When you reach the end of the top
chain support angle you must place the chains on the sprockets
and guide the chain and skimmer flights around the sprockets and
onto the lower chain support angles. (NOTE: Be careful to
prevent the skimmers and chain from misaligning and falling into
the DAF). Repeat procedure until all skimmer flights are
installed. You can use the skimmer drive motor if necessary to
assist but use extreme caution NOT to get caught in pinch points
of the chain or sprockets. The motor rotation can be reversed
by changing the outside power legs. Employ a certified
electrician if not comfortable or familiar with electricity or
Once the chain and flights are
completely installed you will need to remove chain links as
needed to achieve a chain of proper length and tightness. (NOTE
- IMPORTANT: Be sure to remove the same number of links from
both chains to maintain even chain length). The chain should be
tight enough that the middle of the chain length allows no more
than 1” of deflection.
Grease the chains with a suitable
waterproof grease. Hydro-Flo Technologies recommends using a
heavy duty rubber coated cotton glove to push grease into the
crevices of the chain. The grease can be applied as the chain
is moving but use extreme caution NOT to get caught in pinch
points of the chain or sprockets