Initial Start-Up; Preliminary Check; Preparation; Final Adjustment Of Capacity Controls - Carrier 16JT Series Start Up & Operation Manual

INITIAL START-UP

The following start-up procedures are based on a semi-
automatic system in which all pumps energize when the start-
stop switch is placed in the START position.
Preliminary Check —
iary equipment and status of system before starting the ab-
sorption machine.

PREPARATION

1. Add the amount of octyl alcohol specified in Table 5 through
the solution pump service valve. (Refer to Maintenance
Procedures, Adding Octyl Alcohol section, page 35.) Do
not allow air to be drawn into machine.
2. Supply power to control panel, chilled water, and con-
densing water pumps. Open manual steam supply valves,
chilled water valves, and cooling water valves.
3. Place the capacity control and Cycle-Guard™ settings in
AUTO. position and Local/Remote switch in the Local
position. Depress the Start button.
4. When the solution is warm (strong solution below 140 F
[60 C]), place the capacity control auto.-man. button in
MANUAL position and depress the down arrow until valve
is fully closed.
5. Determine the machine absorber loss as described in Main-
tenance Procedures, Absorber Loss Determination sec-
tion, page 31.
If absorber loss is 5° F (2.8° C) or less, place capacity
control valve on AUTO. and allow machine to operate.
If the absorber loss is greater than 5° F (2.8° C), evacuate
the machine (see Maintenance Procedures, Machine Evacu-
ation section, page 33) to remove any noncondensables
that might prevent normal operation. As an alternate pro-
cedure, limit steam pressure to keep strong solution tem-
perature under 140 F (60 C) and allow the purge to re-
move the noncondensables.
After the absorber loss has been reduced to below 5° F
(2.8° C) by either of the above procedures, place ma-
chine on automatic operation, with capacity control but-
ton in AUTO. position and steam pressure normal. The
purge will evacuate the machine to the normal absorber
loss of 2° F (1.1° C) or less.
Table 5 — Octyl Alcohol Initial Charge
16JT
810,812,814
816,818,821,824
828,832,836
841,847,854
857,865,873
880
080
080L,090
090L,100
100L,110
110L,120
120L,135
135L,150
150L
Final Adjustment of Capacity Controls —
low the chiller to operate long enough with a fairly stable
load for the system to reach equilibrium. Verify that the chilled
water temperature is close to the set point and the system is
stable (with little capacity control valve cycling or search-
ing). See Initial Control Checkout and Adjustment, Check
Capacity Control Operation section, page 23, for set point
and control adjustment procedures.
The controller tuning parameters have been factory-
configured for control stability with typical applications.
Check the operation of auxil-
OCTYL ALCOHOL
Gal L
1 3.8
2 7.6
2 7.6
3 11.4
4 15.2
5 19.0
6 22.7
7 26.5
8 30.3
10 37.9
12 45.5
14 53.1
16 60.6
18 68.2
However, if necessary, the parameters can be adjusted for
improved stability with either manual or automatic recon-
figuration procedures.
WITH THE MANUAL PROCEDURE, the configuration for
proportional band, rate, and reset are adjusted until the sys-
tem is stable.
WITH THE AUTOMATIC PROCEDURE, the controller has
AUTOTUNE capability to automatically calculate and ad-
just a particular cooling system's optimal tuning parameters.
See the UDC 3000 Unviersal Digital Controller product
manual for specific description, configuration, operation, and
troubleshooting information.
Final Refrigerant Charge Adjustment —
justment should be made after:
1. Machine is operating with stable temperatures at 40 to
100% of full load.
2. Absorber loss is 3° F (1.7° C) or less.
3. Refrigerant specific gravity is 1.02 or less.
The refrigerant charge is adjusted so that the Cycle-
Guard™ system can limit maximum solution concentration
and avoid solution crystallization. Proceed as follows:
1. Place Cycle-Guard Switch (43RV) in the AUTO. posi-
tion. Then, if the Cycle-Guard valve remains off at least
10 minutes, proceed to Step 2. If not, gradually reduce
the load on the chiller (to reduce the solution concentra-
tion) until the Cycle-Guard valve remains off. The valve
will be energized when the refrigerant high level light is
ON.
2. Remove a solution sample from the solution pump
service valve and measure the specific gravity and
temperature.
3. Locate the intersection point of the specific gravity and
temperature values on equilibrium diagram (Fig. 22A or
22B). Read down from this point to the solution concen-
tration scale to determine the percent lithium bromide by
weight in the weak solution.
4. Determine the approximate percent of full load on the ma-
chine by comparison of chilled water temperature spread,
and flow in relation to design. Enter Table 6 at this per-
cent load and find the corresponding weak solution con-
centrations required for refrigerant charge adjustment.
Table 6 — Weak Solution Concentrations for
Adjusting Refrigerant Charge
REFRIGERANT
LEVEL
High
Mid
NOTE: Concentrations listed in Table 6 are for nominal design con-
ditions. For special design conditions, obtain the special concentra-
tion settings from the factory.
5. Adjust machine operating conditions until machine op-
erates with stable temperatures at either of the weak so-
lution concentrations (±0.1%) listed in Table 6 under the
selected percent load.
To increase the concentration:
Al-
a. Increase the load.
b. Lower chilled water temperature (set point adjuster set-
ting).
c. Raise condensing water temperature (or throttle con-
densing water flow).
After adjusting conditions, repeat Steps 2 and 3 to verify
solution concentration.
25
PERCENT LOAD ON MACHINE
100 90 80 70 60
Weak Solution Concentration (%)
60 60.4 60.8 61.2 61.6
58 58.4 58.7 59.1 59.4
The ad-
50 40
61.9 62.2
59.8 60.1