Level Controller
The neon indicator of liquid level controller indicates the "ON" and "OFF" positions of solenoid
valve. In the proper installation the "ON-OFF"
cycle of the controller is controlled by adjustment
of hand expansion Valve. The hand Expansion Valve should be set such that the Solenoid valve is
“ON” for 10 to 20 minutes approximately. These
timings are only indicative and might vary in
particular application depending upon seasonal
conditions and loading and defrosting conditions.
The golden rule is that the hand Expansion
should be set at full load such that Solenoid
valve remains in the open position approximately
80% of the time and thereby provides smooth flow
of liquid refrigerant to the evaporator. This
will avoid flood back due to surging & short
cycling of the Solenoid Valve. Increase the hand
Expansion setting quarter thread per hour until
the float is full of liquid. This be tested by
ice formation on the float chamber, and if hand
is sticking on the float chamber. Then it definitely
indicates the presence of liquid Ammonia inside,
or simply by monitoring LED display Connect 230
VAC supply on the controller. Keep the level knob
and the differential knob of Electronics Control
panel on '2' & '2' respectively. Keep the
coil connections intact and open the cap of the
float chamber. Remove the coil from the float
chamber keeping the connections intact the dummy
float consists of a pipe which has magnetic properties
identical to the pipe attached to the float and
the movement of the float can be simulated by
inserting the dummy pipe inside the coil.
Whereas Bar Graph display module- indicated
the movement of liquid level inside the float
chamber.
When the pipe is completely inside the coil it
simulates the coil it simulates the float chamber
being full with liquid and the ball being lifted
up completely pushing, the magnetic pipe inside
the Pickup coil. 'The Neon should go "OFF'(all
LED's GLow) stopping the liquid Ammonia through
the solenoid. If it does not go 'OFF', then open
the coil circuit by disconnecting either terminal
3 or terminal 4 (pick-up coil) of the connections
on connection strip. 'Then the Neon indicator
should go 'OFF'. Now, if it does not go 'OFF' then
look for fault (a)-(iii). If it goes 'OFF', then
look for fault (a)-(ii). However, if the insertion
of dummy pipe in the coil makes the neon go 'OFF',
then remove the pipe.Now, if it becomes 'ON' (Only
one or two LED's Glow) then coil and electronic
uint are not faulty. Then check for fault (C)-(i)
and (C)-(ii) given below. Also, if the Neon is
continuously 'OFF ' check for faults. (b)-(i)
and (b)-(ii).
(a) Neon indicator is continuously 'ON'
(The LED display module indicates only one or
two LED's ON)
(i) Check Receiver Liquid Level. May be too low.
(ii) Float coil & coil wiring are faulty.Repalce
the coil or change the coil wires.If the neon
indicator does not go "OFF"
(iii) Electronic unit is faulty.Get it replaced
from the factory.
(iv) Hand expansion setting is too low.Increase
the hand expansion setting quarter thread per
hour until the float is full of liquid.(observe
the LED display)
(v) Ball is struck or punctured.
(b) Neon Indicator is continuously "OFF"
(All LED's are glowing "ON" LED display
panel)
(i) Coil and coil wiring are faulty. Repalce the
coil or change the coil wries.
(ii) Electronic unit is faulty.Get replaced from
the factory.
(iii) Solenoid valve might leaky. Check the coil,
plunger and seat of Solenoid Valve.
(iv) Ball is stuck. Clean Chamber.
(c) The ball in the float chamber is not rising
.
(Few LED's Glow- rise & fall of level is not
observed)
(i) The ball must be sticking or there might be
dirt accumulated on the ball or the ball must
have stuck in the dirt below. Clean the dirt and
other foreign matter.
(ii) The ball itself is leaky or leaking through
the welding. It is recommended to ask for one
from the factory.
(d) Fuse Failure
(1) Check whether it is blown off.
(e) Fuse blows off immediately after power
"ON"
(i) Check Solenoid coil is shorted.
(ii) Check all the parallel paths of solenoid coil
supply such as neon indicator.
LIST OF RECOMMENDED SPARES:
i) Float Ball
ii) Float Coil
iii) Electronics Unit
iv) Gasket
v) Dummy Float |
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