Daikin Altherma HT Service Manual

ESIE09-08B Special Control
Function 51
3.2 Defrosting Operation
The defrost operation is performed to solve frost on the outdoor unit heat exchanger when
heating mode is active to recover the heating capacity.
[Conditions to start]
The defrost operation is started referring following conditions.
 Outdoor heat exchanger heat transfer co-efficient
 Temperature of heat-exchange (Tb) < T
def
*
 Timer (25 min. the minimum)
In addition, outdoor heat-exchanger co-efficient is derived from Tc, Te, and the compressor
load.
*T
def
can vary but is at least -10°C
[Fan defrosting]
 When compressor stops, 80 sec. at low RPM
 At start up compressor, 30 sec. at 950 RPM (step 9)
 Then goes back to normal RPM

Daikin Altherma HT Specifications

General

Type	Air-to-water heat pump
Refrigerant	R-410A
Water Outlet Temperature	Up to 80°C
Operating Temperature Range	-20°C to 35°C
Power Supply	3-phase, 400V
Energy Efficiency Class (Heating)	A++