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F76S WATER FILTERS AND MV876B AUTOMATIC-BACKWASH CONTROLS
62-3015—48
WIRING
CAUTION
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment circuitry.
Disconnect power supply before installation.
IMPORTANT
All wiring must comply with applicable codes and
ordinances.
MV876
1.
Mount the AT140A1034 Transformer and wire as shown
in Fig. 11.
2.
Ensure the F76 air vent is open.
3.
Slowly open the water supply valve.
4.
Once the F76 sump fills with water, close the air vent
and fully open the supply valve.
5.
Reconnect power to the system. When the system is
powered, the MV876 will run through one backwash
cycle (approximately 20 seconds).
6.
Set MV876 backwash interval to the desired setting.
See the Operation section.
7.
Check MV876 operation by interrupting primary power
to the transformer. When power is switched back on, the
MV876 will backwash the F76 once.
Fig. 11. Wiring diagram for F76 with MV876.
OPERATION
The F76S Water Filter removes sediment and debris from the
water using an upper and lower screen. During normal
operation, no water passes through the upper screen. Water
is filtered as it flows through the lower screen. (See Fig. 12a.)
With continued operation, the lower screen becomes
obstructed, reducing efficiency and creating a pressure drop
across the F76S. Backwash the F76S periodically. Suggested
interval is either once per week (residential applications) or
when the black needle measures about five psi lower than the
red needle.
To backwash the F76S manually, open the backwash outlet
on the F76S bottom. This forces the entire filter insert down-
wards. Water flow to the lower screen outer side is blocked.
The upper filter removes sediment and debris from the water.
While the upper screen filters the water. Some of the water
passing through the upper screen is directed through the
impeller to backwash the lower screen (from inside to out-
side). Remaining filtered water meets the needs downstream.
Water jets from the rapidly spinning impeller enhance the
reversed water flow. The reverse flow removes trapped
sediment and debris from the lower filter. This sediment drains
out the backwash outlet. Cleaning the lower screen requires
approximately 20 seconds. See Fig. 12b.
The F76S requires no maintenance if backwashed at the
proper interval.
Determining Backwash Interval
All F76S applications are different and require backwashing at
different intervals. Backwash interval is directly proportional to:
— The level and type of sediment in the local water supply.
— Water usage.
EXAMPLE:In northern states, water usage is higher in
summer months than in winter months due to
lawn watering in the summer. Therefore, the
F76S should be backwashed more often in
summer months than in winter months.
By accurately determining a proper backwash interval, the
F76S will operate at a higher efficiency.
To determine the F76S backwash interval:
1.
Backwash the system once to ensure the lower screen
is clean.
2.
The black pressure gauge needle measures outlet pressure.
With clean screens, inlet pressure equals outlet pressure
because of negligible pressure drop across the F76S.
3.
Rotate the clear gauge cover to set the red needle to
match the black needle.
4.
Record the date and time.
5.
Monitor the F76S closely. Over time, the screens
become obstructed and outlet pressure drops.
NOTE: The F76S requires a backwash when the black
needle measures about five psi lower than the
red needle. Installations do vary and can
require a backwash at different times.
6.
Record date and time again. Residential applications
can require an F76S backwash only once every few
weeks to once per week. Industrial applications can
require an F76S backwash several times a day.
7.
Backwash the F76S regularly at the determined interval.
A backwash can be done manually or automatically.
a. Manual Backwash: Open the backwash outlet for
approximately 30 seconds.
NOTE: The amount of time required varies among
installations. However, 30 seconds is the
standard guideline to clean the lower screen.
b. Automatic Backwash: Install an MV876 Automatic-
Backwash Valve and select the backwash interval.
See the Operation section.
L1
(HOT)
L2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
M16484
MV876