Operating instructions

24 IMM AGSB-60
Figure 21, Typical Field Water Piping
Vent
Drain
Vibration
Eliminator
Flow
Switch
Balancing
Valve
Gate
Valve
Gate
Valve
Water
Strainer
Vibration
Eliminator
Valved
Pressure
Gauge
In
Out
Protect All Field Piping
Against Freezing
Notes:
1. Connections for vent and drain fittings are located on the top and bottom of both evaporator water heads.
2. Piping must be supported to avoid putting strain on the evaporator nozzles.
Water Connections
Water piping to the evaporator must be brought out through the side of the unit between the
vertical supports. The dimensional drawings on page 30 and 31 give the necessary dimensions
and locations for all piping connections. Evaporator piping connections face toward the left
side of the unit when looking at control panel #3.
Refrigerant Charge
All units are designed for use with R-134a and are shipped with a full operating charge. The
operating charge for each unit is shown in the Physical Data Tables beginning on page 27.
Glycol Solutions
When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and
pressure drop through the evaporator can be calculated using the following formulas and
tables.
Note: The following procedure does not specify the type of glycol. Use the derate factors
found in Table 15 for corrections when using ethylene glycol and those in Table 16 for
propylene glycol.
1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced
value, multiply the chiller’s water system tonnage by the capacity (Cap) correction factor
to find the chiller’s capacity when using glycol.
2. Flow - To determine flow (or delta-T) knowing delta-T (or flow) and capacity:
()( )( )
TDelta
factorflowtons
GPM
−
=
24
(Water only, use Flow correction for glycols)
3. Pressure drop - To determine pressure drop through the evaporator when using glycol,
enter the water pressure drop curve at the water flow rate. Multiply the water pressure
drop found there by the "PD" factor to obtain corrected glycol pressure drop.
4. Power - To determine glycol system kW, multiply the water system kW by the factor
designated "Power".
Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in service
stations) to determine the freezing point. Obtain percent glycol from the freezing point table
below. On glycol applications the supplier normally recommends that a minimum of 20%
solution by weight be used for protection against corrosion.