Install Instructions

F76S WATER FILTERS AND MV876B AUTOMATIC-BACKWASH CONTROLS
33-00557—01 8
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 back-
wash cycle (approximately 20 seconds).
6. Set MV876 backwash interval to the desired set-
ting. 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 downwards. 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 outside). 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 differ-
ent times.
6. Record date and time again. Residential applica-
tions can require an F76S backwash only once
every few weeks to once per week. Industrial appli-
cations 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 Auto-
matic-Backwash Valve and select the back-
wash interval. See the Operation section.
L1
(HOT)
L2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
M16484
MV876