Eco-King HWB-299, Installation And Service Manual

Page: 78 / 124

E93.1801EN171 HWB installation manual 78
Store warm hold function
Because of the presence of the indirect tank sensor ( T_Store ) the control can detect demand for holding the tank
hot. If T_Store drops below (115) DHW_Store_Setpoint minus DHW_Store_Hold_Warm the boiler starts at mini-
mum power.
Factory set: 140⁰F
–
5.4⁰F = 134.6⁰F (60⁰C
-
3⁰C = 57⁰C)
So if tank slowly cools down below 134.6⁰F (57⁰C) it will warm up to 147.2⁰F (64⁰C) if there is a consumption of
hot water and the sensor drops below 131⁰F (55⁰C) the boiler will increase it’s power and the normal control will
be active. The boiler stops if T_Store is higher than DHW_Store_Setpoint plus DHW_Store_Hyst_Up.
Relevant variables
Status Variables Value
DHW control state
Central Heating controller state
0

Idle
1

Request
2

Demand
3

Post circulation
4

Off
13.8.2 DHW
MODE
4
DHW mode 4 – Instantaneous water heating with tank and DHW sensor
The DHW mode 4 is the default mode and can be used when using a stand-alone water heater, if waterheaters
are cascaded use DHW Mode 1.
In DHW mode 4 the DHW_Out sensor (
T_DHW ) is used for both detecting DHW tapping and modulating the
burner to the required DHW_Setpoint .
For stand-alone mode only the tank-sensor (DHW-sensor) has to be connected to the water heater.
Demand detection
For DHW mode 4 a demand is present when DHW tapping is detected.
During a demand the burner is started based on the
T_DHW temperature.
Tap start detection
Tap detection for DHW mode 4 is done using the DHW sensor. DHW tapping is detected when:
The T_DHW temperature drops more than Tap_Drop_Delta per second.
Factory set: 1.8⁰F (1⁰C) per second
The T_DHW temperature drops below (48) DHW/Tank Setpoint – Tap_Detect_Hyst_Down .
Factory set: 140⁰F
–
3.6⁰F = 136.4⁰F (60⁰C
-
2⁰C = 58⁰C)
Tap stop detection When the internal tap detection hold timer has elapsed the tap detection can be ended. Un-
der the following conditions a tap stop is detected:
The delta between the
Supply and Return sensor is smaller than Tap_Stop_Delta_Supply_Return .
Factory set: 1.8⁰F (1⁰C) per second)
The delta between the Return and DHW sensor is greater than Tap_Stop_Delta_Return_DHW .
Factory set: 3.6⁰F (2⁰C) per second)
Burn demand The burner is PID modulated in relation to the T_DHW temperature to the DHW_Setpoint .
The burner is started for DHW mode 4 when the following conditions are met:
The
T_DHW temperature drops below (48) DHW/Tank Setpoint – DHW_Hyst_Down.
Factory set: 140⁰F
–
5.4⁰F = 134.6⁰F (60⁰C
-
3⁰C = 57⁰C)
The burner is stopped for DHW mode 4 when the following conditions are met:
The
T_DHW temperature rises over (48) DHW/Tank Se DHW_Hyst_Up.
(48) DHW/Tank Se DHW_Hyst_Up
Factory set: 140⁰F + 5.4⁰F = 145.4⁰F (60C + 3C = 63C)