Aiwa -09CHSRINV/TP11 Service Manual page 17

6. Defrost
Note: t1: compressor continuous works time.
t2: AC unit operation first time going to defrost circle.
t3: compressor accumulated working time (when OPT≤3℃ unit starts to count the time for t3).
When AC unit working to:
a. t1≥t2, or
b. t3≤t1＜t2.
and also the temperature (related to OAT & OPT) tested 3 min continuously meets for defrosting.
1) Defrosting start up: Compressor stops working, and re-starts to working after 50s delay;
2) Conditions for quitting defrosting
a. After defrosting 60s, and OAT≥12℃; or
b. OAT＜－5℃, and OPT ≥8℃ for 80s continuously; or
c. The defrosting for 10 min.
When AC meet any of condition a, b or c, defrosting finish.
3) Defrosting end off: Compressor stops working, and re-starts to working after 50s delay;
7. Cold air prevention:
This function intends to prevent cold air from being discharged when the heating operation starts up
1). IDU fan motor cold air prevention
① .When RT＜24℃:
a. If ITP＞31℃ while compressor works for 5 min, fan motor will work according to preset fan speed.
b. If IPT≤31℃, fan motor stops working while compressor operation within 2min, if IPT≥27℃, fan motor works
in low speed 2 min, then change to preset speed.
② When RT≥24℃:
a. Within 2 min after compressor start up working, once IPT＞27℃, fan motor will change to preset speed.
b. After compressor starts working 2 min, fan motor change to preset speed directly.
2). Vane blade operation for cold air prevention.
a. If the vane works on status of non-swing: While IPT increase to a special degree, the vane blade will change
the position to:
① Default angle; or
② Previous position; or
③ Customer preset.
The above operation can work one time only, when compressor stops working, the unit will once again inspect
the function.
b.
If the vane works on swing: When IDU quits from cold air prevention, vane operate as preset.
8. "8℃" Heating
When function effective, it will make sure the room temperature not lower than 8℃, unit works on heating mode.
Air Conditioner Service Manual
19