Analysis and Solutions to Common Malfunctions of Gas Wall Mounted Boilers

Based on the common faults that occur in gas wall mounted boilers, analyze the causes of the faults according to the symptoms, and provide solutions:

1. Insufficient pressure fault

Fault phenomenon: The water pump does not operate, the controller alarms, and the fault code displayed on the screen is insufficient pressure.     

Reason for malfunction:

a) The pipeline is short of water, and the pressure gauge shows insufficient water pressure in the pipeline.    

b) Pressure switch malfunction.     

c) There is a large amount of air in the pipeline system.    

Solution:

a) Supplement water for pipeline water shortage; If the pipeline leaks, find a way to seal it.     

b) Use a multimeter to check, if the pressure switch is not connected, replace the pressure switch; If there is poor contact, reconnect it; If the circuit is broken, replace the wires; If the wrong terminal is plugged in, connect it correctly.    

c) Exhaust the pipeline system.    

2. Pipeline water shortage fault

① Fault phenomenon: The water pump does not operate, the fan does not operate, the controller alarms, and the fault code displayed on the screen is pipeline water shortage.     

Reason for malfunction:

a) The power cord of the water pump has come loose

b) The water pump doesn't have to lock up for a long time.   

Solution:

a) Use a multimeter to check if the output power supply of the water pump is normal and if the contact is good. If the controller does not have voltage output, it is a controller fault, replace the controller; If the controller has voltage output and the water pump is out of power, it is due to connector detachment, poor contact, or wire disconnection; If it falls off, make good contact again. If there is poor contact, make good contact. If the wire is disconnected, replace it.     

b) If there is voltage input to the water pump but the pump does not rotate, it may be due to the pump being locked. Loosen the flat screw on the water pump, use a flat screwdriver to turn the water pump shaft, and make the water pump rotor rotate to restore normal operation; If the water pump is not locked and a multimeter is used to detect an open or short circuit in the water pump, it indicates that the water pump is burnt out and needs to be replaced.     

② The fault phenomenon is that the water pump is running, the fan is not running, the controller is alarming, and the display screen shows a missing fault code for the pipeline.     

Reason for malfunction:

a) The air in the water pump was not fully discharged, resulting in the water pump running idle.     

b) The heating system distributor is not turned on or the filter is clogged.    

c) There is air inside the pipeline that has not been completely expelled.    

d) Water flow switch malfunction.     

e) The pressure difference generated by the pipeline of the differential pressure type model is insufficient.   

Solution:

a) Unscrew the copper screw on the end face of the water pump, exhaust the air from the water pump, and restart.     

b) If the heating system distributor is not turned on, open the distributor; If the filter is clogged, remove the filter, rinse it clean, install it, replenish water and exhaust, and restart.     

c) If there is air in the pipeline that has not been completely exhausted, exhaust the air and restart.     

d) If the water flow switch fails, use a multimeter to check if there is a switch signal output during operation. If there is a signal output indicating that the water flow switch is turned on, it may be due to poor plug connection or wire disconnection. Please plug in the plug or replace the wire; If the wires and connectors are intact, it is a controller fault and the controller should be replaced. If there is no signal output, it means that the water flow switch is stuck or the waterway is blocked; If the water flow switch is stuck, remove the water flow switch and rinse it before reinstalling it; And replenish water. Exhaust and restart; Water blockage should be handled according to method B.     

e) Install a distributor (switch) at the heating outlet and turn it down slightly.     

3. Fan pressure fault

① Fault phenomenon: The fan does not run or runs slowly, the controller alarms, and the display screen shows the fan pressure fault code.     

Reason for malfunction:

a) The fan is stuck or burned out;     

b) Poor contact of connectors

c) Controller malfunction

d) Capacitor damage

e) The power supply pressure is too low.     

Solution:

a) Use a multimeter to check the fan, disconnect and replace the fan, and replace the fan if it gets stuck.     

b) The connector has poor contact and needs to be reconnected.     

c) Replace the controller due to controller malfunction.     

d) If the fan impeller can be manually pulled to start, it indicates that the capacitor is damaged and needs to be replaced.     

e) Install a voltage regulator to increase the mains voltage to 220V.

② Fault phenomenon: The fan is running normally, the controller does not ignite, the main controller alarms, and the display screen shows the fault code as fan pressure fault.     

Reason for malfunction:

a) Short circuit of wind pressure switch

b) The wind pressure switch is not closed.     

c) Poor contact of connectors.     

d) The suction and exhaust ports are blocked.     

e) Controller malfunction.     

Solution:

a) Use a multimeter to check if the air pressure switch is already closed and connected before the fan starts, then replace the power or adjust the air pressure switch.     

b) If it is normal before the fan starts but does not close after the fan starts, the air pressure switch can be adjusted. If the problem still cannot be solved after adjustment, the air pressure switch should be replaced.; Also check if there is a blockage in the Wenqiu pipe or wind pressure pipe.     

c) If the connector has poor contact, reconnect it.     

d) If all the previous faults have been resolved, check whether the suction and exhaust are smooth or blocked; If the suction and exhaust are not smooth, clean the flue. If it is blocked, clean it thoroughly.     

e) If the faults of a, b, c, and d have been eliminated, then check whether the pulse igniter connector is in good contact and whether the main controller has a 4.5V voltage output. If there is poor contact, then the connection is good; If there is a 4.5V output, replace the pulse igniter; If there is no 4.5V output, replace the main controller.    

1. Ignition failure fault

Fault phenomenon: The pulse igniter ignites normally, but cannot ignite. The main controller alarms and the display screen shows the ignition failure fault code.     

Reason for malfunction:

a) The insulation ceramic body of the ignition needle is damaged or the metal needle is loose, resulting in weak ignition spark.     

b) The power supply of the gas valve is abnormal, causing the solenoid valve to fail to open.     

c) The ignition current regulation of the proportional valve is unreasonable.     

d) The adjustment of the small fire gas flow rate of the segmented valve is unreasonable.     

e) There are foreign objects accumulating in the gas valve, causing it to start poorly.     

f) Poor rubber diaphragm of proportional valve.     

g) The solenoid valve coil is damaged (short circuit or open circuit).     

h) Gas pressure is too high or too low.    

i) Connect the high and low speed lines of the dual speed fan back.     

j) The parameters related to the ignition needle are incorrect.

Solution:

a) Replace the ignition needle.     

b) Replace the main controller.     

c) Adjust the ignition current of the proportional valve reasonably.     

d) Adjust the reasonable flow rate of small flame gas in the segmented valve.     

e) Remove foreign objects from the gas valve.     

f) Replace the gas valve.     

g) Replace the solenoid valve.     

h) Adjust the gas pressure to the rated pressure.     

i) Connect the high and low speed lines of the dual speed fan correctly.     

j) If the distance between the ignition needles is too large or too small, adjust it to 3-4mm; if the direction of the ignition needle is severely skewed, adjust or replace the ignition needle; if the distance between the ignition needle and the burner is too far, adjust it reasonably.     

2. Unexpected flameout fault

Fault phenomenon: After ignition, the engine stalls, the main controller alarms, and the display screen shows an unexpected shutdown fault code.    

Reason for malfunction:

a) Carbon deposition on flame sensing needle.     

b) Poor contact of flame sensing needle connecting wire.     

c) The suction and exhaust ports are blocked or the air inlet of the flue is not extended outside the wall.     

d) The wind outside is too strong.     

e) The gas pressure supplied is abnormal, either too high or too low.     

f) Controller malfunction.     

g) The flame sensing needle does not come into contact with flames.    

h) The flue is not installed properly.     

i) Install the intake and exhaust pipes into the public flue.    

j) The grounding wire has fallen off or broken.    

Solution:

a) Clean the carbon deposits on the flame sensing needle.     

b) The connection wire of the flame sensing needle is well plugged in.     

c) Clean the suction and exhaust ports to ensure smooth suction and exhaust.     

d) Change the position or direction of suction and exhaust.     

e) Adjust the gas pressure to the rated supply pressure.    

f) Replace the controller.     

g) Adjust the flame sensing needle to a position where it can come into contact with the flame during both high and low fires. It is best to be at the junction of the inner and outer flames of the flame.     

h) It is prohibited to connect the intake and exhaust flues to public flues and move them outdoors.     

i) If the cigarette tube is normal after being removed, it means that the cigarette tube is not properly plugged in. Reconnect the cigarette tube.

3. Overheating fault

Fault phenomenon: The wall mounted boiler stalls, the main controller alarms, and the fault display screen shows an overheating and dry burning fault code.     

Reason for malfunction:

a) The heating distributor was closed, causing the water temperature in the main heat exchanger to rise rapidly, and the hot water temperature exceeded 90 ℃, resulting in the opening of the bypass valve.     

b) The heating pipeline is blocked, causing the water circulation speed to slow down and the water temperature to rise rapidly, with the hot water temperature exceeding 90 ℃.     

c) The overheat protection thermostat is faulty and should be normally closed but not normally closed.     

d) The flow switching function of the three-way valve is disrupted (three-way valve type), which may be due to the misalignment of the connecting wire or the misalignment of the ball assembly, as well as poor rotation of the ball, resulting in a small circulation of hot water entering the plate through the three-way valve during heating, causing the water temperature to rise sharply.     

e) Controller malfunction.     

f) Install the distributor (switch) in the opposite direction.     

g) Filter blockage.    

Solution:

a) Open the heating distributor.     

b) Clear the heating pipeline.     

c) Replace the overheat protection thermostat.     

d) Correct the misalignment of the connecting wires; If the ball assembly is misaligned, reassemble the three-way valve ball correctly; If the ball rotates poorly, replace the three-way valve.     

e) Replace the controller.     

f) Reinstall the distributor (switch) in the correct direction.     

g) Clean the filter.    

4. Temperature sensor malfunction

Fault phenomenon: The wall mounted boiler stalls, the main controller alarms, and the display shows a fault code for the heating or hot water sensor.     

Reason for malfunction:

a) The temperature sensor is short circuited.     

b) The temperature sensor is open circuit.    

Solution:

a) If the insulation layer of the connecting wire in the circuit is damaged and short circuited, replace the wire; If the temperature sensor is damaged, replace it; Replace the controller if it is damaged.     

b) If the connection in the circuit is broken or poorly connected, replace the wire and reconnect it; If the temperature sensor is damaged, replace it; If the controller malfunctions, replace the main controller.     

5. Although the open wall mounted boiler is operating normally, the water tank is overflowing.

Fault phenomenon: Water tank overflow.     

Reason for malfunction:

a) The automatic water replenishment valve is stuck with debris and cannot block the tap water, causing the tap water to flow into the heating water and overflow.    

b) The internal leakage of the plate heat exchanger causes overflow.     

c) The heating system is too large and does not match the expansion tank, causing overflow.     

Solution:

a) If foreign objects accumulate on the rubber film of the automatic water replenishment valve, causing poor sealing, remove the foreign objects; If the water replenishment valve is not tightly closed, replace the automatic water replenishment valve.     

b) Replace the plate heat exchanger.     

c) Install check valves on heating pipelines or replace large capacity open water tanks.     

6. Although the enclosed wall mounted boiler is operating normally, the pressure continues to rise.

Fault phenomenon: The pressure on the water pressure gauge keeps rising, and the pressure relief valve drips water for a long time.    

Reason for malfunction:

a) The manual water replenishment valve itself cannot block the tap water due to malfunction, causing tap water to enter the heating system.    

b) Internal leakage of plate heat exchanger or water integrated system.     

Solution:

a) Remove foreign objects from the sealing rubber of the manual water replenishment valve or replace the sealing rubber.     

b) Replace the plate heat exchanger or the entire waterway integrated system.     

7. Heating heats up quickly, but the radiator does not heat up.

Fault phenomenon: The wall mounted boiler quickly reaches the set temperature, but the radiator is not hot and the ambient temperature cannot rise.     

Reason for malfunction:

a) There is a large amount of air in the heating system that has not been fully exhausted.     

b) The heating system is blocked, causing slow water circulation.     

c) There are many distributors that are only slightly open and have slow water flow.     

d) The heating system is too large and the water pump power is not enough.     

e) The impeller of the water pump is damaged.     

f) The controller outputs abnormal water pump voltage.     

g) The power gear adjustment of the water pump is unreasonable.     

h) The bypass valve does not reset.   

Solution:

a) Drain the air from the system.    

b) Clean the heating system filter.    

c) Reasonably open the distributor.     

d) Add one more water pump to increase circulation.     

e) Replace the impeller of the water pump or replace the water pump.     

f) Replace the controller.     

g) Adjust the water pump to a reasonable gear.    

h) Reset the bypass valve.

8. The heating system is normal, but some radiators are not heating up.

Fault phenomenon: Other radiators are normal, but one or two radiators are not hot or one or two groups of radiators are not hot.     

Reason for malfunction: The opening of the radiator distributor that is not hot in this group is too small or there is air inside.     

Solution: Increase the opening of the distributor or remove air from the radiator.     

9. The heating system is operating normally but the ambient temperature cannot rise.

Fault phenomenon: The water temperature of the heating system rises and the standby mode is normal. The radiator temperature is also basically normal, but the room temperature is not high, which cannot achieve the heating effect.     

Reason for malfunction:

a) The power of the selected model is too low and does not match the large heating area.     

b) The number of selected heater groups is too small, and the heating area is not matched (the standard heat dissipation of each cast iron 760 standard piece is 130W).     

c) The radiator has severely scaled.     

d) The gap between the underfloor heating system pipes is too large.    

e) The bypass valve of the waterway integration system does not reset.

Solution:

a) Replace the high-power wall mounted boiler.     

b) Replace the large radiator.     

c) Clean and descaling the entire system or replace the radiator.    

d) Only by increasing the flow rate of water.     

e) Reset or replace the bypass valve.     

10. Heating is normal, but hot water does not come out or cold water comes out.

Fault phenomenon: It is very normal in the heating state, but it does not ignite or the hot water temperature is not hot when switching to the hot water state.     

Reason for malfunction:

a) If the hot water faucet is turned on while heating, but the running light does not light up, it is caused by a malfunction in the hot water flow switch.     

b) In summer, when the heating is turned off and the hot water faucet is turned on, if cold water comes out, it is a malfunction of the hot water flow switch or the heating water flow switch.     

c) The running light is on, but no hot water is coming out. Firstly, touch the surface of the heating pipe. If it is warm, it indicates that the three-way valve has malfunctioned and has not been turned to hot water mode; The three-way valve is normal. If the touch panel is replaced on both sides without heat exchange, and one side is hot and the other is cold, it is a damage to the panel.     

d) If hot water does not come out during trial operation, it is because the tap water and hot water connection are reversed, and the flow switch does not operate, resulting in no hot water coming out.     

Solution:

a) Replace the hot water flow switch.     

b) If the heating water flow switch fails, replace the heating water flow switch. If the hot water flow switch fails, replace the hot water flow switch.     

c) Replace the three-way valve due to malfunction; Replace the faulty board.     

11. The use of hot water is normal, but it cannot provide heating when switched to heating mode.

Fault phenomenon: The domestic water heater is normal, but it cannot enter the heating state.     

Reason for malfunction:

a) If the distributor is turned off, it will display a water shortage fault in the pipeline.     

b) Excess air remains in the wall mounted boiler and heating piping.     

c) The three-way valve is only in a hot water state.     

d) The return water filter has accumulated a large amount of foreign matter, which hinders the circulation of heating water.     

e) The heating piping is blocked, and the heating water cannot circulate.     

Solution:

a) Open the distributor.     

b) Exhaust the air completely.     

c) If the contact of the hot water flow switch is always closed, replace the hot water flow switch; If the three-way valve malfunctions and causes the heating system to be shut down, replace the three-way valve.     

d) Remove the filter and clean the return water filter core.     

e) Clean the heating piping.   

12. The noise is too loud.

Fault phenomenon:

a) When igniting, there is a roaring sound inside the wall mounted boiler.     

b) Excessive noise caused by ignition delay.     

c) The noise emitted during combustion is too loud.     

d) The noise of boiling water during heating is too loud.     

e) The noise of the water pump is too loud.    

f) Machine vibration during operation.     

Reason for malfunction:

a) Due to excessive gas volume during initial ignition.     

b) Excessive or insufficient spacing between ignition needles can cause irregular ignition. Or faults caused by the malfunction of the pulse igniter itself.     

c) Due to the length and number of bends of the flue not meeting the regulations (2 bends of 3m); And the exhaust pipe produces noise due to the loss of airtightness, causing the exhaust gas to be absorbed; The gas pressure is too high; The maximum current of the proportional valve is set too high.     

d) When the heating water is heated to a higher temperature in the combustion heat exchanger, boiling noise will occur. This excessive noise is caused by poor water quality or poor welding of the main heat exchanger fins. e) There is air inside the pipeline.     

f) Poor connection of smoke exhaust pipe or inappropriate opening position of smoke exhaust pipe.     

g) The smoke exhaust pipe is connected to the public flue.     

h) The gas pressure is too high.     

i) Unbalanced fan generates vibration.   

Solution:

a) Adjust the gas pressure when the air pressure is too high; If the gas valve is a proportional valve, reduce the proportion. Valve ignition current, if the gas valve is a segmented valve, adjust the small flame regulator to reduce the small flame gas flow rate. b) Adjust the distance of the ignition needle or replace the pulse generator.     

c) Improper installation of chimney and correction of installation; If the chimney leaks, seal it with tin foil or replace the chimney.    

d) Improve water quality or replace heat exchangers.     

e) Drain the air from the system.     

f) Move the smoke pipe from the public flue to the outside.     

g) Reduce gas pressure or turn off gas.    

h) Adjust the soft connection point of the fan to balance it.     

13. The constant temperature of domestic hot water is too long or cannot be maintained.

Fault phenomenon:

a) Water fluctuates between cold and hot, and cannot remain constant.    

b) The water temperature is too high.     

c) The water temperature needs more than three minutes to maintain a constant temperature.

Reason for malfunction:

a) Due to unstable water flow or gas pressure, water temperature fluctuates.     

b) Due to the low water flow rate, the water temperature is too high.     

c) Due to water quality reasons, the water flow sensor rotates unevenly or the water flow rate is too small, as well as poor contact of the inlet temperature probe.     

Solution:

a) Add water flow stabilizer and gas stabilizer.     

b) Install a pipeline pump at the tap water inlet to increase the water flow rate.    

c) Clean the water flow sensor or ensure good contact between the inlet water temperature probe and the copper pipe wall