SHERPA SHW
Sanitary water heat pump
23
11.4
MAIN LOGICS
11.4.1
Water temperature difference for compressor starting
Parameter 1 “water temp. difference TS6” is used to control the compressor on or off.
When down tank temperature T2 is lower than setting temperature TS1-TS6, the compressor will work to heat the water until
reaching the setting temperature TS1. On the display the top part temperature T3 of the water tank is always visualized.
11.4.2
External pump
T2: lower tank temperature
T3: upper tank temperature
Checks to be done to use the external pump:
parameter 14 has been configured;
the optional probe T6 has been electrically and hydraulically connected;
the external flow switch (optional) has been electrically and hydraulically connected;
an external pump (not provided) has been electrically and hydraulically connected.
When used for sanitary hot water circulation, the pump will start when the below conditions are satisfied at the same time:
1.
Wired controller is ON;
2.
T3 ≥ parameter 15+parameter 16;
3.
T6 ≤ parameter 15-5°C
The pump will stop when one of the below conditions is satisfied:
1.
Wired controller is OFF;
2.
T3 ≤ parameter 15-2°C;
3.
T6 ≥ parameter 15
When used for solar water circulation, the pump will start when the below conditions are satisfied at the same time:
1.
Wired controller is ON;
2.
T6 ≥ T2+parameter 17
3.
T2 ≤ 78°C
The pump will stop when one of the below conditions is satisfied:
1.
Wired controller is OFF;
2.
T6 ≤ T2+parameter 18
3.
T2 ≥ 83°C
Pump anti-block function: when the pump stops for 12 hours, it will be forced to run for 2 min.
11.4.3
Flow switch
After the pump is running for 30 sec, if the water flow switch signal is checked to OFF for 5 sec, the pump stops. The pump will
restart after 3 min. If this malfunction occurs 3 times in 30 min, the pump can not start until the unit is re-powered. The relating
error code will be shown on the controller. Only the pump will be stopped but not the unit itself.
11.4.4
Thermal protections
First step protection: when the tank water goes up to 85°C, the unit will stop and the relating error code will be shown on the
controller. This is an auto-reset protection. When tank water temperature goes down, the unit can start again.
Second step protection: when the tank water keeps going up and reaches 90°C, the manual reset cut-off will be active, the
electrical heater stops, unless you manual reset the protector.
To manual reset the protector, remove the frontal plastic cover and press the reset red button on the thermostat.
11.4.5
Disinfection weekly cycle
The unit is programmed to activate a weekly anti-Legionella cycle for a period of 30 minutes that brings the tank water to 70°C.
This system allows to reduce the risk due to bacteria that causes various diseases, commonly known as "Legionella". It ‘s
recommended to read this paragraph and to ask explanations to your installer/plant designer in order to be properly informed
about the risk of spreading this disease. We strongly advised you to read the "Guidelines for prevention and control of
legionnaires' disease - Approved in the State-Regions Conference of May 7, 2015- Italy and subsequent amendments, which must
be taken as a reference for designing the plant.
The operation of the disinfection cycle is as follows:
The heater will start each week at the setting time (parameter 13) automatically, regardless if the machine is
ON
or in standby
mode (i.e. the unit is off but remains connected to the power supply)
When upper tank temperature T3 ≥ TS3 (parameter 4), the heater stops. When T3≤TS3-2°C, the heater starts.
The water temperature T3 is kept in range TS3-2°C to TS3 for the set disinfection time t2 (parameter 5), then the unit quits the
disinfection.
When parameter 5 (t2) is set to 0, the disinfection function is disabled.
