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8.3.3 INDICATION: LIKELY REASON: REMEDY:
Differential pressure
across the
FMA 5400A/5500A
controller is within
specification but flow
rate reading is more
than 1% F.S. below set
point value when 100%
set point is applied.
Valve
compression
spring is over
adjusted and
controller does
not have enough
power to open
valve and reach
100% F.S. flow.
1. Make sure differential pressure across
the FMA 5400A/5500A is within
specification.
2. Adjust control set point to 100% F.S.
This should remedy initial fault
conditions (flow reading is less than set
point value and difference is more than
1% F.S.).
3. See operating manual page 17 (Figure
6-1). Unscrew hex nut cover on the top
of the solenoid valve.
4. Using screwdriver readjust adjustment
screw on the top of the valve to CCW
(counter clock wise) direction until
reading on the display will be equal to
the set point value. Be very careful
during adjustment: make only 15
degree turn each time and wait about
15 seconds due to sensors responds time.
If reading still below 100% make
another 15 degree turn. Do not over
adjust valve. If you noticed that flow
rate is constant and more than 105%
of full scale, it means you over adjusted
valve and it has leakage. In this case
make adjustment to CW (clock wise) in
order to fix this problem until reading
will go back to 100% full scale.
5. Install zero set point (or valve close
command), wait about 3 minutes and
check if valve is able to close.
6. This is not a shut off valve. It is normal
to observe up to 0.5 % of F.S. leakage.
7. Install hex nut cover on the top of the
solenoid valve.
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