Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
84
7.74.3.9.2. Modulating Step Common
When a RO is being used with an AO the AO will key off the RO turning on. The RO will turn on when the discharge
pressure enters the bottom of the CND HI/LO ZONE (Setpoint #193). At that time the AO will move to its starting %
(Setpoint #49). The AO will stay at its starting % until the discharge pressure gets outside the top of the CND HI/LO
ZONE (Setpoint #193). At that point the AO will modulate based on Setpoints #51, #53-55. Now if there are 2 RO’s
tied to the AO and the “AO Starting Stage” is 1 then once the AO gets to 100% the 2
nd
RO will be turned on after a
delay (value in the ”MIN VFD Opening“ cell for Setpoint #48) and the AO will be set back to its minimum % (Setpoint
#52) and then modulate as described above. Now if the pressure begins to fall and goes below the CND HI/LO ZONE
(Setpoint #193) the AO will modulate. Once the AO gets to its minimum % (Setpoint #52) the 2
nd
RO will be turned off
after a delay (value in the “MAX VFD Opening” cell for Setpoint #48) and the AO will be set back to 100% and continue
to modulate as needed.
If the “AO Starting Stage” is 2 then when the discharge pressure enters the bottom of the CND HI/LO ZONE (Setpoint
#193) the 1
st
RO (stage 1) will be turned on. The 2
nd
RO will turn on once the discharge pressure gets outside the
Heating Info CND HI/LO ZONE (Setpoint #193) and the delay has been met (value in the “MIN VFD Opening cell” for
Setpoint #48) at that time AO will be set to its starting % (Setpoint #49). If the discharge falls below the CND HI/LO
ZONE (Setpoint #193) the AO will begin to modulate. Once the AO reaches its minimum % (Setpoint #52) it will turn
off the associated RO after a delay (value in the “MAX VFD Opening” cell for Setpoint #48). The 1
st
RO will remain on
until the discharge pressure falls below the CND HI/LO ZONE (Setpoint #193) and the delay has been met (value in
the “MAX VFD Opening” cell for Setpoint #48).
7.74.3.9.3. Modulating Individual
This type of condenser uses water to provide cooling to the compressors. The AO Modulating Valve will modulate the
cold water based upon this discharge pressure for each circuit. You may also select Relay Outputs to be turned
ON/OFF while modulating the Analog Output.
The individual condensers must be set up in the Circuit Base screen.
The control will be similar to the Modulating Common type, except that the discharge pressure for each circuit will
control its own condenser.