40
Solution Flow Control
Solution Pump Speed Setup
The solution pump AFD’s are factory programmed.
However, the actual minimum and maximum speed of the
Low Generator Temperature Solution Pump (LTSP) solution
pump may require some adjustment to fine-tune the
operating range for proper and efficient operation. The ABS
AFD simply follows the changes made to the Low
Generator Temperature Solution Pump (LTSP). Increasing
the Minimum of the Low Generator Temperature Solution
Pump (LTSP) will automatically increase the ABS pump
minimum speed, and so forth. [The ABS will operate at
different speeds than the Low Generator Temperature
Solution Pump (LTSP) for each given point.] . (See AFD
section for more information.) The minimum Low
Generator Temperature Solution Pump (LTSP) speed must
be low enough for good turndown of chiller capacity;
however, not too low as to cause SDR trips. See SDR
section. The maximum speed must be set to accomplish
full load without losing the liquid level in the absorber
sump, which should run about 1" below the ABS water
box.
Figure 7 illustrates the selectable Low Generator
Temperature Solution Pump (LTSP) range of the total drive
output frequency range. The machines operating range are
less than the capabilities of the AFD. A maximum
frequency of 65 Hz and a Minimum speed of 20 Hz are
factory programmed into the LTSP AFD. The minimum and
maximum operating points within that range are defined
with UCP2. The next two setpoints define the operational
range of the LTSP by setting the minimum and maximum
flow speeds.
Figure 7 – Selectable LTSP range - solution flow automatic speed
drive control (2 - 10 volts)
26. Solution Pump AFD Minimum Frequency Setpoint
This setpoint will set the UCP2 minimum flow output signal
in hertz for the LTSP.
Selectable Range is 20 to 65 Hz in increments of 1. Module
Default is 20. Typical setting of minimum is 27-32 Hz.
27. Solution Pump AFD Maximum Frequency Setpoint
This setpoint will set the UCP2 maximum flow output
signal in hertz for the Low Generator Temperature Solution
Pump (LTSP).
Selectable Range is 20 to 65 Hz in increments of 1. Module
Default is 60. Typical maximum speed is 48.
Energy Input
ABDA 48Hz, ABTF 54-60 Hz, ABSD
Energy input means direct-fired Burner or indirect fired
steam or hot water.
The next three entries setup the energy-input requirements.
28. EV Maximum Travel Setpoint
This Menu is only displayed on steam or hot water units
Range of Values for ABS is 0 to 60,000 Steps in increments
of 100 Steps. All 90-degree rotational stepper actuators are
16,300 steps. Module Default is 16,300 Steps.
With burners, the value will be determined after the burner
min and max fire rates are established during startup.
(100%=10v, 10% = 1vdc.)
29. Energy Input Closed Stop
Energy input closed stop is the minimum input position for
energy input.
On direct-fired machines this is the burner minimum fire
rate position. The feedback voltage at (Gas) low fire
position times 10. Such as, [1.5 Vdc times (10% or 1vd)]
=15%
On steam or hot water machines with valves, the typical
min open stop is 0% [Horizon] adaptive, 10% non-adaptive.
Range of Values is 0 to 100% in increments of 1%. Module
Default is 10%.
30. Energy Input Open Stop
Energy input open stop is the adjustable maximum limit
selected on direct-fired machines. This is the burner
maximum fire rate position. The feedback voltage at (Gas)
high fire position times 10. Such as, [9.5 Vdc times (10% or
1vd)] = 95%. See Figure 8.
With heat source valves, the typical max open stop is
50-80% for non-adaptive, 100-120% for adaptive.
Range of Values for ABS is 0 to 100% in increments of 1%.
Module Default is 100%
Figure 8. Direct-fired energy input burner control output
(0 - 10 volts)
Allowable Service Setting Range (%)
PWM Output (Volts)
100
10v
0
0v
Allowable Service Setting Range (%)
Primary Fuel Operating Range (Always 0-100)
Alternate Fuel Operating Range (Always 0-100)
Adjustable Minimum Stop
(Primary Fuel)
Adjustable Minimum
Stop (Alternate Fuel)
Adjustable Maximum Stop
(Both Fuels)
10%
30%
85%
Solution Pump AFD
Adjustable Maximum Stop.
For Example 45 hz
Fixed Maximum
65 Hz (10 volts
Note 1: The PWM voltage below 2 volts is not valid during any running or stop mode.
This voltage is only during a module reset.
Note 2: The Operational range is displayed in the Cycle Report and can be adjusted
manually from Service Tests .
The Ajustable Minimum and Maximum Stops can be set in the Field Startup sub-menu
within Service Settings.
Note 3: For more information on procedures to set the min and max stops on the UCM,
see the Mechanical Interface - Electrical (Hardwired) section of this chapter.
Fixed Minimum
20 Hz (2 volts)
0 volts
Allowed Frequency of AFD Operation
Solution Pump AFD
Adjustable Minimum Stop.
For Example 25 Hz
Note 1
Automatic and Manual Operational Range
(0-100)