Daikin EWYQ130DAYN [393/524] Automatic defrost

ESIE06-05 Functional Control for a Standalone Unit

Part 2 – Functional Description 2–167

3.22.3 Automatic defrost

Defrost forbidden

timer

Defrost forbidden timer.

This is the minimum time between 2 defrost cycles in order to keep the heating capacity and to prevent

frequent defrosting.

■ The timer can be

- Normal startvalue (def 30 min, range 20 - 120 min).

- Short start value (default 10 min, range 1 - 20 min).

■ If timer is not on 0, the defrost cycle cannot be started.

■ The timer starts counting from previous defrost finished.

■ In case of a safety stop, the timer starts counting.

■ In case of thermostat-OFF, counter does not reset and keeps on counting.

■ If during countdown of the timer, timer selection is modified from normal to short, and the already

time past is larger than the short timer value ==> timer is put on 0.

Defrost start

conditions

A = “start const temp”, default 12 °C (can be changed between 5 - 25°C).

Ta = ambient temperature sensor

Tr = coil sensor

(in case of EWYQ230/250 : lowest temperature of 2 coil temperature sensors = Tr)

During compressor operation, above conditions should be met for 5 min before defrost will start. If less

than 5 minutes, re-detect again.

AND

Defrost forbidden timer T(min) must be zero

Conditions were met at time

of coil sensor failure

1) Ta-Tr> 0.4 x Ta+A

2) Tr < 0°C

3) Ta < 10 °C