Buffer Overheat Protection

The overheat protection is active only in case the buffer is in the operation mode charging control, this means it is charged from one of the controlled heat generators.

In case that the buffer upper sensor is above the maximum upper OVHT-01 (90 °C) or the buffer effective lower temperature is above OVHT-02 (80 °C), a forced switch-off of the buffer loading will be triggered.

If any of the two temperature limits is exceeded, the outputs "BypassValve1" to “BypassValve4“ will be set to “bypass“ and the heat demand will not be transmitted to the output “HeatDemandOut”.

If any of the two temperature limits is exceeded for a time longer than the buffer alarm delay OVHT-03, a buffer alarm will be generated at the output “BufOverheatAlm“.


When both the:

by the fixed switching differential OVHT-04 (2 K), the alarm is reset and the buffer charging from the controlled heat generators can restart.


Table 8.   Parameter List Buffer Overheat Protection

Description

Value Range

Default Value

Unit

OVHT-01: maximum buffer upper temperature

0 … 150

90

°C

OVHT-02: maximum buffer lower temperature

0 … 150

80

°C

OVHT-03: alarm delay for maximum alarm (0 = off)

0 … 10000

60

sec

OVHT-04: switching differential buffer alarm

0 … 50

2

K