Nova-Tech Pulsatron Plus Series T7 - Manual (Page 11)

11
The signal cord polarity is:
Black = Common
White = Positive
Wrong polarity can result in excess flow.
Signal input impedance is 124 ohms.
Remove cap from pump socket labeled 4-20 mA, use polarized cord supplied with pump to connect control circuit to
pump. Plug cord into pump socket labeled 4-20 mA.
6.0 MAINTENANCE
Before performing any maintenance or repairs on chemical metering pumps, be sure to disconnect all
electrical connections, insure that all pressure valves are shut off and pressure in the pump and lines has been
bled off.
Always wear protective clothing, gloves and safety glasses when performing any maintenance or repairs on
chemical metering pumps.
6.1 Routine Maintenance
Routinely check the physical operating condition of the pump. Look for the presence of any abnormal noise, excessive
vibration, low flow and pressure output or high temperatures [when running constantly at maximum stroke rate, the pump
housing temperature can be up to 160˚F (70˚C)].
For optimum performance, cartridge valves should be changed every 6-12 months. Depending on the application, more
frequent changes may be required. Actual operating experience is the best guide in this situation.
Repeated short-term deterioration of valve seats and balls usually indicates a need to review the suitability of wetted
materials selected for the application. Contact the supplier for guidance.
Check for leaks around fitting or as a result of deteriorating tubing e.g. when standard white translucent discharge tubing
is exposed to direct sunlight. Take appropriate action to correct leak by tightening fittings or replacing components.
Keep the pump free of dirt and debris as this provides insulation and can lead to excessive pump temperatures.
If the pump has been out of service for a month or longer, clear the pump head valve assemblies by pumping fresh water
for approximately 30 minutes. If the pump does not operate normally after this “purging run”, replace cartridge valve
assemblies.
6.2 Disassembly and Assembly
Diaphragm Removal
Flush pump head and valve assemblies out by running pump with water or other suitable neutralizing solution. Wash
outside of pump if chemical has dripped on pump. Set stroke length knob of pump to 0% and unplug pump.
Depressurize the system and disconnect tubing or piping from the pump. Remove the four pump head screws and then
remove the pump head assembly.
Remove the diaphragm by grasping it at the outer edge and turning it counter
clockwise until it unscrews from the electronic power module (EPM). Don’t
lose the deflector plate or diaphragm shims which are behind the diaphragm,
they are needed for re-assembly. Note shim quantity may be from 0 to 2.
Inspect diaphragm, if it is intended to be used again look for indications of the
PTFE face being overstretched, (localized white areas) or the elastomer on
the back of the diaphragm being worn. Excessive amounts of either condition
require diaphragm replacement.
6.3 Diaphragm Replacement
When replacing the diaphragm, it is always a good idea to replace the valve
cartridges and other worn parts. A kit is available from your supplier with all
parts necessary to completely rebuild your pump’s wet end. All your supplier
needs to know is the “KOPkit No.” on your pump’s data label to supply this kit.
Set pump stroke length at 50% and unplug the pump.
If you kept the shims from the original diaphragm or know the original quantity you can avoid the next step for shimming
the diaphragm.