Grundfos BACnet IP, Функциональный профиль и руководство пользователя

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7.4 Coil preheat and frost protection
When choosing the application type Heating coil , you can activate
the coil preheat and frost protection functions.
Coil preheat
With MIXIT you can preheat the coil before allowing the fan to start.
Frost protection
You can protect the coil from freezing by defining an air and return
flow temperature. If the temperature falls below one of the two
temperature limits, MIXIT will react by fully opening the valve in
order to circulate hot water in the system.
The return flow temperature is measured by the sensor in port B of
MIXIT. To measure the air temperature, you will need to install a
temperature sensor in the coil.
7.4.1 Setting coil preheat
The function can be active only for heating coil applications and can
only be set via Grundfos GO Remote.
Grundfos GO Remote menu:
Main menu
> Settings > Application settings > Coil preheat and
frost protection
1. Activate the function by pressing the grey slide-button.
2. Press Coil preheat temperature to define a return
temperature threshold.
Read the system state via MI,2 (Status System State [Enum]). If
MI,2 is set to 4, MIXIT is preheating the coil.
ID Object name R/W Description
MI,2
Status
System State
[Enum]
R
1: Powering up (~30 s)
2: Fault (fault relay activated)
3: Ready (ready relay activated)
4: Preheating heating coil
5: Temperature control state
6: Coil frost protection
7: Underfloor overheat protection
8: Shut down due to removal of start
signal
9: Auto tuner on
10: Valve 100 % open (for backup)
11: Return temperature control.
7.4.2 Setting frost protection
The function can be active only for heating coil applications.
1.
Frost detection is enabled by setting BO,4 to 1. When enabled,
the valve opens fully. Default value is 0.
2. Return temperature limit and air temperature limit is configured
via Grundfos GO Remote:
Main menu > Settings > Application settings > Coil preheat
and frost protection
a. Activate the function by pressing the grey slide-button.
b. Press
Frost return temperature limit to define a return
temperature threshold. Press OK .
c. Press Frost air temperature limit to define an air
temperature threshold. Press OK .
d. Press Forced pump start to define a temperature threshold
for the antifreeze sensor. Press OK
Read the system state via MI,2 (Status System State [Enum]).
If coil frost is detected, a notification is given via BI,7 to 1.
ID Object name R/W Description
BO,4
Simulate
Frost
Protection
W
0: Disable frost protection (default)
1: Enable frost protection
BI,7
Notification
Coil Frost
Risk
Detected
R
0: Not detected
1: Detected
The notification is not resettable but
it will reset itself
MI,2
Status
System State
[Enum]
R
1: Powering up (~30 s)
2: Fault (fault relay activated)
3: Ready (ready relay activated)
4: Preheating heating coil
5: Temperature control state
6: Coil frost protection
7: Underfloor overheat protection
8: Shut down due to removal of start
signal
9: Auto tuner on
10: Valve 100 % open (for backup)
11: Return temperature control
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