Common faults and troubleshooting methods of plate heat exchangers

1.What should I do if the unit fault indicator light is on, that is, the yellow indicator light on the control cabinet is on? The fault indicator light is on, indicating that the corresponding water pump is overloaded, the motor current is greater than the rated current, and the thermal relay has played a protective role. The method to reset it is to press the reset button on the thermal relay. Note that resetting can only be done after the thermal relay has cooled down, otherwise resetting is invalid.

2. The system is under pressure, but the pressure gauge shows 0. What's going on? If the needle valve matched with the pressure gauge is in the closed state, the pressure gauge will always display 0. During the operation of the system, ensure that the pressure gauge matching needle valve is fully open.  

3. What are the reasons for the system not heating up? How should it be analyzed? The temperature of the secondary water supply is low and not hot. The analysis shows the following reasons: insufficient flow rate of the primary side water supply: check whether all valves in the primary side water supply and return pipelines are open. Check if the water supply filter is clogged once. If all valves are open, check the pressure difference between the supply and return water again. If the pressure difference is less than 0.05 MPa, please ask the heating company to increase the flow rate. If the pressure difference between the primary supply and return water is greater than 0.15MPa, please clean the heat exchanger. Secondary system malfunction: Check if all valves in the secondary supply and return water pipelines are open. The secondary side filter is clogged. The pressure difference between the inlet and outlet of the secondary side heat exchanger is higher than 0.15MPa, and the heat exchanger is blocked. Please clean the heat exchanger.

4. What's the reason why the system can't replenish water? The water replenishment pump keeps running, but the pressure does not increase.

If the water replenishment pump keeps running but the pressure does not reach the set value, please exhaust the system. Poor water replenishment is mostly caused by gas collection in the system.

5. What is the reason why the variable frequency water replenishment is not automatic and the variable frequency drive does not start? Check if the transfer switch is in the variable frequency or automatic position. The frequency converter can only work normally when it is in the variable frequency or automatic position. Check if the start button of the water replenishment pump is in operation. The frequency converter can only work normally when the green indicator light of the water replenishment pump is on. Check if there are any alarm codes on the control panel of the frequency converter. The numbers starting with F are the fault codes, and the numbers starting with R are the warning codes. The warning codes do not affect the operation of the frequency converter. After the fault code appears, the frequency converter must be reset before it can continue to work. If a fault code appears, please press the EXIT button in the upper left corner of the inverter operation screen. All three conditions mentioned above must be met in order for the variable frequency water replenishment to function properly.

6. What should be done when the temperature of the secondary water supply is too high? If the user feels that the water supply temperature is too high and the room is too hot, the method is to close the primary side water supply valve.

Please note that the primary water supply valve must be closed and the return valve must be fully open.

7. What is the reason for excessive noise from the water pump? During one to two heating periods, the unit may experience increased noise due to mechanical wear and tear. Check if the fan cover is loose and exhaust the pump.

The water pump needs to be regularly maintained, lubricated, and vulnerable parts replaced.

8. What is the reason for the rapid drop in pressure after the water replenishment pump stops replenishing water frequently? If the unit frequently replenishes water after a long period of normal operation, please perform the following checks: check if there are any pipeline or valve leaks in the secondary side system, etc. Check if the check valve in front of the water replenishment pump is not tight and if there is backflow. The inspection method is to first stop the water replenishment pump, close the inlet valve of the water replenishment pump, and then open the exhaust valve at the outlet of the water replenishment pump. If water is discharged, it indicates that the check valve in front of the water replenishment pump is not tight and needs to be replaced.

9. What's going on when one circulation pump is turned on while the other is also running? During the operation of the unit, if one circulating pump is turned on and the other circulating pump also rotates in reverse, it indicates that the check valve in front of the unopened pump is not tight and needs to be replaced. If it cannot be replaced temporarily, please close the butterfly valves before and after this pump to prevent water backflow.

10. If a shielded pump is configured on the unit, how to determine if the pump's direction of rotation is correct?

The method to determine whether the direction of the shielded pump is correct and reliable is to use a clamp type ammeter to measure the current. The current for forward rotation is greater than the current for reverse rotation.

11. What is the reason why the start and operation indicator light of the pump is on, but the pump is not running?

Check the circuit breakers in the control cabinet and make sure they are all in the suction state.