Common problems and troubleshooting methods of heat exchangers
I. Explanation of the terminology of the heating unit
1. Primary side: refers to a heat source, such as hot water or steam in a boiler room.
2. Secondary side: refers to hot users, such as floor heating, radiators, central air conditioners, etc.
3. Water supply: Whether it is the primary side or the secondary side, the hot water is the water supply, that is, the high temperature pipeline is the water supply.
4. Backwater: Whether it is the primary side or the secondary side, the cold water is the return water, that is, the pipeline with low temperature is the return water.
5. High-temperature water: Water with a temperature higher than or equal to 100 degrees, the national standard is 130/80 degrees, that is, the water supply temperature is 130 degrees, and the return water temperature is 80 degrees.
6. Low-temperature water: water with a temperature lower than 100 degrees, the national standard is 95/70 degrees, that is, the water supply temperature is 95 degrees, and the return water temperature is 70 degrees.
Note: Both high temperature water and low temperature water are defined for the primary side system.
Second, the unit normal operating parameters display rules
1. The water supply temperature is higher than the return water temperature, and the water supply pressure is higher than the return water pressure.
2. The difference between the primary side water supply pressure and the return water pressure should be greater than or equal to 0.05 MPa.
3. The difference between the inlet and outlet pressures of the secondary side of the Plate heat exchanger should be less than or equal to 0.15 MPa.
4. If the primary side is high temperature water, the temperature difference between the water supply temperature and the return water temperature cannot be higher than 40 degrees.
5. If the primary side is low temperature water, the temperature difference between the water supply temperature and the return water temperature cannot be higher than 25 degrees.
6. If the secondary side is heating the radiator, the temperature difference between the water supply temperature and the return water temperature cannot be higher than 25 degrees.
7. If the secondary side is floor heating or air conditioning heating, the temperature difference between the water supply temperature and the return water temperature cannot be higher than 14 degrees.
Third, common faults and troubleshooting methods
1. The unit fault indicator is on, that is, the yellow indicator on the control cabinet is on. What should I do?
When the fault indicator is on, the corresponding pump is overloaded, the motor current exceeds the rated current, and the thermal relay is protected. The method of releasing it is to reset by pressing the reset button on the thermal relay. Note that it must be reset after the thermal relay has cooled down, otherwise the reset will be invalid.
2. The system is under pressure, and the pressure gauge shows 0. What happened?
If the needle valve of the pressure gauge is closed, the pressure gauge will always display 0. During the operation of the system, ensure that all the pressure gauges attached to the pressure gauge are fully open.
3. What is the secondary side overpressure? What about overpressure? How to prevent overpressure in the secondary system?
When the system is initially running, the secondary temperature is relatively low. After the hydration reaches the constant pressure value, as the temperature increases, the pressure of the secondary system will also rise. At this time, one must exhaust more, and the second is to Drain the water. When draining water, open the drain valve of the secondary return line. After the system temperature is stable, the pressure will not rise any more.
