andrews CWH 30/201 Operating Instructions Manual page 38

4.5 COMPLETE PARAMETER LIST TABLE (CONTINUED)
PARAMETER DESCRIPTION
DHW (continued)
1660 Pump release
DHW release
With this parameterization, the circulating
pump is released when DHW heating
is released also.
1661 Pump cycling
1663 Circulation setpoint
Boiler
2300 Frost protection for plant
boiler pump
DHW Storage tank
5012 DHW forced charging
5020 DHW setpoint boost
5024 DHW switching diff erential
Engineer
FACTORY NOTES
DEFAULT
Time pro- Set desired option for activation of the DHW circulation pump
gramme 5 (see below)
Time program 4/DHW
The circulating pump is released accord-
ing to time program 4 / DHW.
Off When switched on, the circulation pump will cycle on and
off during the activation period (on for 10 minutes then off
for 20 minutes repeatedly). This function is especially useful
where the heat losses on the return pipework are high and the
burner is operating continually for long periods of time, with
little or no DHW draw off .
45 o C When B39 sensor is installed in the DHW distribution return
pipe, the controller will monitor the return temperature during
the activation time of the pump. Whenever the temperature
acquired by the sensor falls below the circulation setpoint, the
pump is kept running until the setpoint is reached (minimum
on time is 10 minutes).
During a legionella cycle operation the temperature at the
sensor is used to adjust the dwell time, ensuring that the en-
tire DHW system reaches the legionella setpoint for the total
dwell time length set. The dwell time counter is not started un-
til the temperature at the sensor reaches legionella setpoint.
On When turned on the pump is activated when the temperature
in the heat exchanger drops below 5
On The fi rst charge activation of the day is calculated using a
switching diff erential of 1
rameter 5024
0 C Used by the control strategy to calculate the internal fl ow
o
temperature required to raise the actual water temperature to
the DHW set point.
Examples:
A boost of 2
draw off temperature could be 2
Burner effi ciency will decrease slightly with a higher boost.
A boost of -2
water draw off temperature will be at no higher than tank
setpoint. Burner effi ciency will increase slightly with a lower
boost.
2 C Defi nes by how much the temperature of the water in the
O
DHW tank can drop below set point before recharging takes
place. This diff erential applies both to the Nominal as well as
the Reduced DHW tank setpoint
38
Time program 5
The circulating pump is released accord-
ing to independent time program 5.
O C
C regardless of the setting of pa-
O
C will reduce the re-charging time ,but the water
O
C above the tank setpoint.
O
C will increase the re-charging time ,but the
O
MAXXfl o EVO