OEM DC BWA-SS-7 Installation And Maintenance Instructions Manual page 27

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Before the Degree Minute reach - 60 (adjustable) ,the compressor is off, but when the Degree Minute
reach - 60 (adjustable) ,the compressor automatic start, and the flow temperature will begin increase.
(Higher than desired temperature) when the actual water supply temperature reach / higher than the
desired temperature, the DM will be changed.
For example : the DM was cumulated to -160 in this time.
1 minutes later when the Feed water temperature higher than desired temperature for 1 .
10X1=10 , Degree Minute= -150;
Another 1 minutes later when the Feed water temperature higher than desired temperature for
2 . 10X1=10, Degree Minute= -140;
Another 1 minutes later when the Feed water temperature higher than desired temperature for
3 . 10X1=10, Degree Minute= -130;
Another 1 minutes later when the Feed water temperature higher than desired temperature for
4 . 10X1=10, Degree Minute= -120;
........................
Compressor off when Degree Minute reach 0 (adjustable) .
The relationship between compressor and DM
The relationship between compressor (on and off) and DM,the relationship between heater(on and off)
and DM.
The above chart is describing that running of compressor and electrical heater depend on Integral
The compressor's DM is -60 start, 0 is off, A0=-60 startup.
Electrical heater 1 's DM is -500 start,when the feed water temperature reach the setting value the electrical
heater is off, A0+A2=-60-440=-500 start up.Electrical heater 2 / 3 is the same principle.
The constant temperature function is only available in Room heating, but not in water tank heating.
Constant temperature function has two kinds: Integral (DM) and Constant room temperature
1. The constant area diagram: T1, room return water temperature, Ts, room air setting temperature
or feed water temperature.
Degree Minute s(DM) instruction
Control