Coil Defrost - Lennox CLIMATIC 60 User Manual

COMPONENTS

COIL DEFROST

Function
The CLIMATIC™ 60 manages defrost procedure to avoid ice on the evaporator coil in heating pump mode (winter season).
Description
To avoid the icing of the external air exchanger during winter operating, it's necessary to reverse the refrigerant cycle. There are 2
defrost mode:
• cyclic mode,
• dynamic mode (not available in the software CH060 vers.01-rev.0.1).
The defrost procedure is activated if the following conditions are met during 1 minute:
• the outside air temperature is ≤ (3562),
• one of the compressor(s) on the circuit has been running for a time ≥ (3564) since the last defrost,
• the saturation temperature is ≤ (3563).
The defrost procedure is characterized by the following steps:
1. stop the compressors on the concerned circuit,
2. wait for 30 s to equalise the pressure in the circuit,
3. start all compressors on the circuit (if the outlet T° is not too low),
4. reverse the reversing valve when ΔP>2 bars,
5. start all condenser fans when the HP ≥ 55.0°C in order to dry the coil,
6. stop all condenser fans when the HP ≤ 40.0°C,
7. repeat the steps 4. to 5. 3 times,
8. stop the compressors on the concerning circuit,
9. wait for 1 min to equalise the pressure in the circuit,
10. end of procedure; restart the unit in heating mode.
11. reverse the reversing valve when ΔP>2bar.
Note
• In case of alarm on the circuit during the defrost procedure, the defrosting is cancelled.
• If the HP pressure doesn't reach 55°C after 6 min, during the step 6, the defrost procedure is cancelled.
• During the step 4 the compressor(s) could not start in order to not decrease too much the water temperature of the system.
Compressor in defrost
Settings
The different settings to adjust the defrosting procedure are available in the menu:
• (3561): defrost mode (cyclic, dynamic),
• (3562): minimum of outside air temperature to enable defrost procedure,
• (3563): critical saturation temperature to enable defrost procedure
• (3564): minimum of interval time to enable defrost procedure.
• 16 •
Outlet water temperature (°C)
CL60-AC CHILLER-IOM-1011-E