Service manual

Overview of the heating mode functions ESIE03–01
2–40 Part 2 – Functional Description
3
1
2
4
5
3.2 Defrost Control
Applicable units P RYP71-125L
Purpose The purpose of the defrost control is to prevent frost on the outdoor heat exchanger coil. This frost
forms when the unit is in heating position.
Starting conditions:
RYP71-125L
The defrosting starts when either condition 1 or 2 has been realized.
Condition 1 Condition 2
The compressor has been running for a total of 25 min accumulated since the start of heating
operation or since the end of the previous defrosting.
P Outdoor heat exchanger temp. ≤ -3°C, and
P Outdoor heat exchanger temp. ≤ 0.4 x Ta - 5°C
P Compressor ON ≥ 5 min continuously,
and integral heating capacity diminishes
(see further in this section), or
P Ta > -5°C for 3 h accumulated
(if DS1-3 is ON, 40 min), or
P Ta ≤ -5°C for 6 h accumulated
Above condition for 10 min accumulated.
Outdoor fan is ON (not in O.L. control) Outdoor fan is OFF (O.L. control)
-
15 -10 -5
-5
-1
-3
-7
-9
05
Outdoor heat exchanger
temp. (Tc) (°CDB)
Outside air
temp. (°CDB)
Defrost activation range