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periodic inspections are a necessary means to keep your Magnetrol level control in good working order. This control
is, in reality, a safety device to protect the valuable equipment it serves. Therefore, a systematic program of "preven-
tive maintenance" should be implemented when control is placed into service. if the following sections on "what to
do" and "what to avoid" are observed, your control will provide reliable protection of your capital equipment for many
years.
WhaT TO DO
1. keep control clean
nEVER leave switch housing cover off the control. This
cover is designed to keep dust and dirt from interfering
with switch mechanism operation. In addition, it protects
against damaging moisture and acts as a safety feature
by keeping bare wires and terminals from being
exposed. Should the housing cover become damaged
or misplaced, order a replacement immediately.
2. inspect switch mechanisms, terminals and connec-
tions monthly.
– Mercury switches may be visually inspected for short
circuit damage. Check for small cracks in the glass
tube containing the mercury. Such cracks can allow
entrance of air into the tube causing the mercury to
"oxidize". This is noticeable as the mercury will appear
dirty and have a tendency to "string out" like water,
instead of breaking into round pools. If these condi-
tions exist, replace the mercury switch immediately.
– Dry contact switches should be inspected for exces-
sive wear on actuating lever or misalignment of
adjusting screw at point of contact between screw
and lever. Such wear can cause false switch actuat-
ing levels. Adjust switch mechanism to compensate
(if possible) or replace switch.
Do nOT operate your control with defective or malad-
justed switch mechanisms (refer to bulletin on switch
mechanism furnished for service instructions).
– Magnetrol controls may sometimes be exposed to
excessive heat or moisture. Under such conditions,
insulation on electrical wires may become brittle,
eventually breaking or peeling away. The resulting
"bare" wires can cause short circuits.
Check wiring carefully and replace at first sign of brittle
insulation.
– Vibration may sometimes cause terminal screws to
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) may need resetting.
• 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.
pREVEnTiVE MainTEnancE
TROUBLEShOOTing
work loose. Check all terminal connections to be cer-
tain that screws are tight. Air (or gas) operating medi-
um lines subjected to vibration may eventually crack
or become loose at connections causing leakage.
Check lines and connections carefully and repair or
replace, if necessary.
nOTE: As a matter of good practice, spare switches should
be kept on hand at all times.
3. inspect entire unit periodically
Isolate control from vessel. Raise and lower liquid level
to check for switch contact and reset.
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.
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 mecha-
nism still fails to actuate, check installation of control to
be certain it is within the specified three (3°) degrees of
vertical. (Use spirit level on side of enclosing tube in
two places, 90° apart.)
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, consult
factory.
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