Charging Pump Command On/Off Control

The charging pump start depends on the domestic hot water valve configuration.

When the controller is requested to warm up the buffer, "enable charging control" is ON, see chapter "On/O ff Control"

Configuration with a 3-way Bypass Valve, CFG-01 = 2

The charging pump starts when the internal controller requests to warm up the buffer. This pre-circulation allows the system flow temperature to rise.

The valve will open 100% when the following conditions are fulfilled

The valve closes and the pump stops if the buffer completely charged or the system flow temperature is lower than the buffer upper temperature (UWT).

Configuration with a 2-way Valve, CFG-01 = 3

The valve will open when the internal controllers requests to warm up the buffer and the system flow temperature is high enough to prevent forced cooling down of the buffer. The pump will start only after the valve is open. The charging pump will be released after a time, defined by the parameter PRP-01. This start-up delay is important only if a two-way valve is configured. In all the other configurations, the pump start-up delay is "0". The valve opens 100% and the charging pump starts with a start-up delay defined by the parameter PRP-01 if:

The valve closes and the pump stops if the buffer IS completely charged or the system flow temperature is lower than the buffer upper temperature (UWT).

If you do not connect the valve, set the pump start-up delay PRP-01 = 0.

For all configurations the primary pump will be switched off after the switch off delay defined by parameter PRP-02.

Overrides for Both Configurations

The pump will also start if one of the following protection functions is active:

Table 7.   Parameter List

Description

Range

Default

Units

SST-01: temp. difference primary/ secondary system

0...60

10

K

PRP-01: start-up delay primary/ secondary pump

0...600

120

sec

PRP-02: switch off delay primary pump

0...600

0

sec