Magnetrol A10, Installation And Operating Manual

Page: 11 / 40

45-610 Displacer Type Liquid Level Switches and Proof-er
®
Switches 11
4.1.2 Test control’s performance
1. Reconnect power supply and carefully actuate switch
mechanism manually, using a non-conductive tool on elec-
trical switch mechanism, to determine whether controlled
equipment will operate.
Caution:
With electrical power on, care should be taken to avoid
contact with switch leads and connections at terminal
block.
2. If controlled equipment responds to manual actuation
test, trouble may be located in level sensing portion of the
control (displacers, spring, stem, and magnetic attracting
sleeve).
NOTE: Check first to be certain liquid is entering tank or vessel.
A valve may be closed or pipe line plugged.
3. With liquid in tank or vessel, proceed to check level sens-
ing action by removing switch housing assembly.
Caution:
Be certain to pull disconnect switch or otherwise assure
that electrical circuit(s) through control is deactivated.
Close operating medium supply valve on controls
equipped with pneumatic switch mechanisms
a. Disconnect wiring from supply side of switch
mechanism(s) and remove electrical conduit or operating
medium line connections to switch housing.
b. Relieve pressure from vessel and allow unit to cool.
c. Remove switch housing assembly by loosening set screws
located at the bottom of the housing base.
4. With switch housing assembly removed, inspect attraction
sleeve and inside of enclosing tube for excessive corrosion
or solids buildup which could restrict movement, prevent-
ing sleeve from reaching field of switch magnet.
5. Inspect displacer stem and spring assembly to assure it
is not damaged. If stem or spring is bent or otherwise
damaged, movement of the attraction sleeve inside the
e-tube will be restricted, preventing proper function of
the control.
6. If trouble is still not located, proceed to remove the entire
sensing unit from the tank or vessel by unbolting head
flange or unscrewing mounting bushing. Inspect displacer
assembly and all internal parts for any signs of damage.
Check assembly for binding by supporting head flange or
mounting bushing over the edge of a bench and move
displacer assembly by hand.
NOTE: When in doubt about the condition or performance of a con-
trol, contact the factory or consult your local representative.