Liebert 8 Tons User Manual

Reheat element sheets and fins are manufactured with stainless steel. Regular inspections are neces-

sary to assure proper cleanliness of the reheating element. Should inspection reveal corrosion parti-

cles on the reheating element or adjoining surfaces (including ducts and plenums), appropriate 

cleaning should be performed. Periodic replacement of the reheating element may be necessary to 

meet specific application requirements.

Each month the components of the refrigeration system should be inspected for proper function and 

signs of wear. Since in most cases evidence of malfunction is present prior to component failure, peri-

odic inspections can be a major factor in the prevention of most system failures. Refrigerant lines 

must be properly supported and not allowed to vibrate against ceilings, floors, or the unit frame. 

Inspect all refrigerant lines every six months for signs of wear and proper support. Inspect the capil-

lary and equalizer lines from the expansion valve.

Suction pressure will vary with load conditions. Suction pressure normally ranges from 58 psi to 75 

psi (405 kPa to 517 kPa). When the 3-ton circuit is operating alone, the upper range of suction pres-

sure may approach 100 psig. This is a function of the unit design and is acceptable for scroll compres-

sors.

The discharge pressure will vary greatly with load and ambient conditions (Table 16). The high-pres-

sure switch will shut the compressor down at its cut-out setting.

The thermostatic expansion valve keeps the evaporator supplied with enough refrigerant to satisfy 

load conditions. Proper valve operation can be determined by measuring superheat level. If too little 

refrigerant is being fed to the evaporator, then the superheat will be high. Conversely, if too much 

refrigerant is being supplied, then the superheat will be low. The correct superheat setting is between 

10 and 15°F (5.6 and 8.3°C). Only the 5-ton valve is adjustable.

Restricted airflow through the condenser coil will reduce the operating efficiency of the unit. Addi-

tionally, it can result in high compressor head pressure and loss of cooling. Using compressed air or 

commercial coil cleaner, clean the condenser coil of all debris that will inhibit airflow. In winter, do 

not permit snow to accumulate around the side or underneath the condenser. At the same time check 

for bent or damaged coil fins and repair as necessary. Check all refrigerant lines and capillaries for 

vibration and support as necessary. Carefully inspect all refrigerant lines for signs of oil leaks.

Each water or glycol-cooled condensing unit has a coaxial condenser consisting of an exterior steel 

tube and an interior copper tube. If the water supply is clean, coaxial condensers do not normally 

require maintenance or replacement. Should your system begin to operate at high head pressure with 

reduced capacity, and all other causes have been eliminated, the condenser may be obstructed or 

fouled and should be replaced. 

Air-Cooled

180-275

(1242-1895)

Water-Cooled

65ºF to 85ºF water

(18 to 29.4ºC)

200-225

(1380-1550)

Glycol-Cooled

210-275

(1445-1895)

Maximum

330

(2275)

High Pressure Cut-Out

360

(2480)