Toshiba HWS-1501CSHM3-E(-UK), HWS-802XWHT6-E, HWS-802H-E 8-2Piping freeze prevention control

Item		Operation flow and applicable data, etc.
8-3.	8-2) Piping freeze prevention control 2
Hydro Unit	TC and TWO activates freeze prevention regardless of a heat pump operation mode.
Control	1) Determination condition: TWO>20°C, 2*TC+TWO<-12°C is continuously detected for 30 seconds or longer. Or
	TWO	20°C, TC+TWO<4°C is continuously detected for 30 seconds or longer.

2)Determination cancellation conditions

•The stop or operation mode is changed by the remote controller

•The mode is defrosting at the time of determination

At the next time of defrosting, the start condition is not met.

•The mode is other than defrosting at the time of determination

After cooling, heating, hot water heat pump restarts, the start condition is not met for 10 minutes.

3)Error display

•If freeze determination cancellation condition is not met, A4 error is displayed.

8-3) Piping freeze prevention control 3

This control applies only when defrosting is in operation.

1)Determination condition: During defrosting, TWI 15°C is continuously detected for 30 seconds or longer (After the stop, the unit restarts.)

2)Determination cancellation condition

•At the next time of defrosting, the start condition is not met.

3)Error display

•If freeze determination cancellation condition is not met, A4 error is displayed.

8-4) Piping freeze prevention control 4

When the value of Ps sensor is low, freeze prevention is activated regardless of a heat pump operation mode.

1)Determination condition: Lo pressure sensor detects PS < 0.2 MPa and 30 seconds passes (defrosting and cooling) (During a defrosting operation for cooling and heating, or hot water supply)

Lo pressure sensor detects PS < 0.2 MPa and 10 minutes passes (heating and hot water supply operation)

2)Determination cancellation condition

•After a restart, the start condition is not met for 30 minutes.

•At the next time of defrosting, the start condition is not met. (Defrosting operation for heating or hot water supply)

3)Error display

•If freeze determination cancellation condition is not met, A8 error is displayed.

9)High return water protect control.

The hydro unit protects against high return water which made by separate boiler system.

TWI, TWO, THO

A02 error detect

70

(Diff : 2K)

Normal operation

When A02 error appeared, the built-in pump will stop.

55