AHU algorithm. The act of transition to winter mode
Our organization is also engaged in the operation of ventilation systems. An example of the act of translating the unit for winter operation under the cut ..
ACT
transfer of K2 (MIK) air conditioning system to winter operation
October 05-13, 2010 Moscow
The representatives of the contractor and the customer transferred the K2 air conditioning system to the winter mode of operation:
1. The parameters of the coolant at the nodes of regulation:
- supply pressure 5.4 - 3.8 bar;
- pressure in the return pipe 4.8 - 3.5 bar;
- temperature in the supply pipe 68 - 62 ° C;
- the temperature in the return pipe 38 - 28 ° C.
2. Outdoor temperature + 7 ° С. The air temperature setting is set to 23 ° C. The output of the installation at the specified temperature is made within 50 - 60 minutes in the temperature range of 12 - 23.5 ° C.
3. When checking the anti-freeze protection mode, the restart is performed in manual mode, the heater does not warm up. When the anti-freeze protection is triggered, the control valve of the control unit does not open automatically.
As a result of the translation revealed:
1. The pressure of the network coolant in the supply and return pipes is not stable, the pressure drop is reduced to zero, resulting in the threat of freezing the heater, the temperature values of the air supplied to the room is not provided.
2. The control valve of the 1st heating is open at 100%, the additional heating of the air to the specified temperature value is carried out by the valve of the 2nd heating.
3. Values of the percentage of valve opening displayed, on the LCD controller do not coincide with the opening value of the valve on the control units.
4. The development of the algorithm for protecting the installation from freezing is not provided for in full.
5. The control algorithm of the controller does not match the controlled system.
6. October 13, 2010: The algorithm of the controller does not provide the air conditioner operation in the normal “Winter” mode (the operation of the 1st and 2nd heating valves causes the air conditioner to be in the “Threat of freezing” mode, the ACU is activated).
Taken measures:
1. The Customer’s representative made an additional adjustment of the pressure of the network coolant in the CHP. The pressure in the supply line is 5.0 bar, the pressure in the return line is 4.0 bar.
2. Measures were taken to fill the heating pipelines of the 2nd heating with the coolant and to release air from the heat supply system.
3. The adjustment of the air damper drive has been carried out.
4. October 13, 2010: The 2nd heating and KKB node is disabled.
Findings:
1. The required pressure drop of the network coolant in the MIC housing must be at least 0.5 bar.
2. Perform replacement of instrumentation, valves, pumps and valves on the control units of the 1st and 2nd heating.
3. The existing SHAU does not provide for normal operation and heating of the heater, depending on the outdoor temperature.
4. The controller does not provide the air conditioner in normal operation, replacement is necessary.
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