4
1.
System Conductivity
- The conductivity function of the controller is designed to monitor and control
Total Dissolved Solids (TDS) in a recirculating system like a cooling tower or boiler in terms of
electrical conductivity measured in MicroSiemens/cm. This control function is also referred to as
Bleed.
2.
Make-up or Miscellaneous Conductivity
-This conductivity with the probe installed in the fresh
make-up water line can be used to control the conductivity of the tower in terms of cycles of
concentration by calculating the difference between the make-up water’s conductivity and the
system’s conductivity. It can also be used to monitor another conductivity with no feed timers
associated with it..
3.
pH
- The pH function monitors and controls pH on a scale of 0-14 pH units.
4.
ORP
- The ORP function monitors and controls ORP on a scale of +/- 1000 mV.
Chemical Feed Timers
Chemical feed timers are designed to automate the addition of various chemicals by activating a relay output.
Multiple timers can be supplied depending upon the model number and each timer will include a relay output.
All timers can be programmed to be one of the following types.
1.
Pulse Time
- Accepts pulses from a make-up water meter (supplied separately). It can accumulate
1-9999 gallons before activating the timer to run.
2.
Feed with Bleed
- Activates the relay output simultaneously with the bleed and limits the amount
of time the relay output will be on during the bleed cycle.
3.
Feed after Bleed
- Activates the relay output based on a user defined percentage of time based
on the bleed off, another timer or digital input. The relay is activated after a bleed cycle and runs
for the set percentage of that bleed cycle.
4.
Percentage
- The relay is on for a percentage of a continuously repeating cycle time that can be
set from 1 minute to 99 hours and 59 minutes.
5.
28 Day
- The timer is based on a 28 day cycle with four independent programmable feed cycles
with prebleed and bleed lockout settings.
II. Installation
Electrical Wiring
The MegaTron controller has an internal regulated fused power supply that will operate off of 90 to 250 VAC
at 47 to 63 Hz on the incoming wiring. Each output relay is individually protected with a replaceable fuse.
Relay outputs will equal incoming line voltage.
WARNINGS:
1. The controller should be connected to its own isolated circuit breaker, and for best
results, the ground should be a true earth ground, not shared. Wiring must be done
according to all applicable local codes.
2. Power (line voltage) must be disconnected while making any connections. If power is
supplied to the unit, line voltage will be present on the relay cards located in the
lower section of the enclosure, even with the power (ON/OFF) switch off.
3. Low voltage signal wires (probes, flow switch, water meter, etc.) should never be run
in conduit with high voltage (like 115VAC) wires.
4. Units should be ordered with the appropriate option to provide powered relays designed for the
incoming/outgoing power.
NOTE: Liquid tight fittings and some labeled signal leads are provided for all signal
(low voltage) connections for both pre-wired and conduit units.
Summary of Contents for MegaTron
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