• Drain and air vent connections must be provided at all low and high points in the piping to
facilitate drainage of the system and to vent any air in the pipes.
• Use insulation and heater tape or a suitable glycol solution to protect liquid system lines that
are at risk of freezing due to low ambient temperatures. Use the liquid pumps to ensure that
liquid is circulated when the ambient temperature approaches freezing point.
• Install insulation around the evaporator nozzles. Use heater tape of 21 W/m under the
insulation, supplied independently, and controlled by an ambient temperature thermostat set
to switch on at approximately 4°F (2.2°C) above the freezing temperature of the chilled liquid.
• Evaporator heater mats are installed under the insulation, and are powered from the chiller's
HTR DIST panel. In sub-freezing conditions, unless the evaporator has been drained or an
appropriate water-to-glycol concentration is maintained, high voltage power to the chiller must
be maintained to ensure the heater mats assist in evaporator freeze protection. If there is a
potential for power loss, drain the evaporator or replace the water in the chilled water circuit
with an appropriate water-to-glycol concentration.
CAUTION
Any debris left in the water piping between the strainer and evaporator could cause serious damage
to the tubes in the evaporator and must be avoided. Be sure the piping is clean before connecting it to
the evaporator. Keep evaporator nozzles and chilled liquid piping capped before installation to ensure
construction debris is not allowed to enter.
CAUTION
The installer or user must also ensure that the quality of the water in circulation is adequate, without
any dissolved gases, which can cause oxidation of steel or copper parts within the evaporator.
• Check the chemical specification of water in the following table for chemical consideration.
Table 13: Chemical consideration of water
Water content
Concentration
Time limit (analyze before)
Alkalinity (HCO
3
-
-)
70 to 300 ppm
Within 24 hr
Sulfate (SO
4
2-
)
˂ 70 ppm
No limit
HCO
3
-
/SO
4
2-
˃ 1.0
No limit
Electrical conductivity
10 to 500 µS/cm
No limit
pH
7.5 to 10
Within 24 hr
Ammonium (NH
4
+
)
˂ 2 ppm
Within 24 hr
Chlorides (Cl
-
)
˂ 100 ppm
No limit
Free chlorine (Cl
2
)
˂ 1 mg/l
Within 5 hr
Oxygen
˂0.02 mg/l
Within 5 hr
Hydrogen sulfide (H
2
S)
˂0.05 mg/l
No limit
Free carbon dioxide (CO
2
)
˂ 5 mg/l
No limit
Total hardness (odH)
4.0 to 8.5 mg/l
No limit
YVAM Air-Cooled Centrifugal Liquid Chiller
36
