7
PREVENTIVE MAINTENANCE (cont.)
TROUBLESHOOTING
WHAT TO AVOID
1. NEVER leave switch housing cover off the control longer
than necessary to make routine inspections.
2. NEVER use lubricants on pivots of switch mechanisms.
A sufficient amount of lubricant has been applied at the
factory to insure a lifetime of service. Further oiling is
unnecessary and will only tend to attract dust and dirt
which can interfere with mechanism operation.
3. NEVER place a jumper wire across terminals to "cut-
out" the control. If a "jumper" is necessary for test pur-
poses, be certain it is removed before placing control
into service.
4. NEVER attempt to make adjustments or replace switch-
es without reading instructions carefully. Certain adjust-
ments provided for in Magnetrol controls should not be
attempted in the field. When in doubt, consult the facto-
ry or your local Magnetrol representative.
Usually the first indication of improper operation is failure of
the controlled equipment to function, i.e.: pump will not
start (or stop), signal lamps fail to light, etc. When these
symptoms occur, whether at time of installation or during
routine service thereafter, check the following potential
external causes first.
— Fuses may be blown.
— Reset button(s)
— Power switch may be open.
— Controlled equipment may be faulty.
— Wiring leading to control may be defective.
If a thorough inspection of these possible conditions fails to
locate the trouble, proceed next to a check of the control’s
switch mechanism.
CHECK SWITCH MECHANISM
1. Pull disconnect switch or otherwise disconnect power to
the control.
2. Remove switch housing cover.
3. Disconnect power wiring from switch assembly.
4. Swing magnet assembly in and out by hand to check
carefully for any sign of binding. Assembly should
require minimal force to move it through its full swing.
5. If binding exists, magnet may be rubbing enclosing
tube. If magnet is rubbing, loosen magnet clamp screw
and shift magnet position. Retighten magnet clamp
screw.
6. If switch magnet assembly swings freely and
mechanism still fails to actuate, check installation of con-
trol to be certain it is within the specified three (3°)
degrees of vertical (Use spirit level on side of enclosing
tube in two place, 90° apart. Refer to Figure 3 on page 4).
7. If mechanism is equipped with a mercury switch,
examine glass mercury tube closely as previously
described in “Preventive Maintenance” section. If switch
is damaged, replace it immediately.
8. If switch mechanism is operating satisfactorily, proceed
to check sensing unit.
CHECK SENSING UNIT
1. Check to be certain liquid is entering float chamber. A
valve may be closed or piping plugged.
2. Proceed to check level sensing action by removing
switch housing assembly, as described in Steps 4
through 7 of the “Switch Differential Adjustment” section
on Page 5.
CAUTION:
Unit must be normalized to atmospheric pres-
sure before removing switch housing assembly.
3. Inspect attraction sleeve(s) and inside of enclosing tube
for excessive corrosion or solids build-up which could
restrict movement, preventing sleeve(s) from reaching
field of magnet(s).
4. If the differential has been changed in the field, check
tightness and position of the jam nuts.
NOTE: Differential adjustment causes a change in the
amount of level travel between “switch-on” and “switch-off”
actuations. Refer to Page 5.
5. Fill chamber with liquid at room pressure. Check float(s)
to be certain it is buoyant in the liquid (float chamber
must have adequate liquid level). If float is determined
to be filled with liquid or collapsed, entire float chamber
assembly (sensing unit) should be replaced.
CHECK COMPLETE UNIT
Reassemble unit. Reconnect power supply and carefully
actuate switch mechanism manually (using a non-conduc-
tive tool) to determine whether controlled equipment will
operate.
CAUTION:
With electrical power “on”, care should be taken
to avoid contact with switch leads and connec-
tions at terminal block.
If all components in the control are in operating condition,
the trouble must be (and should be) located external to the
control. Repeat inspection of external conditions previous-
ly described.
NOTE: If difficulties are encountered which can not be
identified, consult with the factory or your local repre-
sentative for assistance. A complete description of the
trouble should be provided along with information con-
cerning your piping and mounting arrangement, plus a
description of your operation sequence. Sketches or
photographs showing the installation are also benefi-
cial.
When communicating about your control, be certain
always to specify the complete Model and Serial num-
bers.
Summary of Contents for 075
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