Hamworthy QAA73.210, Installation, Commissioning And Servicing Instructions

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HAMWORTHY HEATING LTD QAA73.210
Programmable Room Unit
500001305/B
Summer / winter changeover temperature (SUWI) :
The summer / winter changeover temperature is the criterion for automatic summer / winter changeover of the
heating plant.
It offers the following benefits:
•
Fully automatic operation throughout the year
•
The heating will not be switched on when the outside temperature drops forshort periods of time
•
Additional savings function
By changing the setting, the respective periods of time will be shortened or extended. The change will only affect
the heating circuit.
Increase: Winter operation will start earlier Summer operation will start later .
Decrease: Winter operation will start later Summer operation will start earlier
To determine changeover, the setting of the summer / winter changeover temperature ( ± a fixed switching differ-
ential) is compared with the attenuated outside temperature.
Note: This func-
tion only acts in automatic mode.
The 24 - hour heating limit is used to switch the heating on and off in the course of the day, depending on the out-
side temperature. This function is used primarily during spring and autumn to respond to short - term temperature
variations.
Example:
By changing the value entered, the respective heating periods will be shortened or extended.
Increase: Heating mode will start earlier , changeover to ECO later .
Decrease: Heating mode will start later , changeover to ECO earlier .
Setting line e.g.
Comfort setpoint (TRw) 22 °C
24 - hour heating limit (THG) - 3 °C
Changeover temperature (TRw - THG) heating
off
= 19 °C
Switching differential (fixed) - 1 °C
Changeover temperature heating on = 18 °C
Legend
TAged Attenuated out-
side temperature
SuWi Summer / winter
changeover temperature
T Temperature
t Time in days
H Heating
18