How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask George-Allsorts Your Own Question
George-Allsorts, Senior Appliance Technicial Manager
Category: Appliance
Satisfied Customers: 1448
Experience:  A whitegoods technician with 30+ years service in Domestic Appliance Service & Repair, and General Mechanical & Electrical Repair
Type Your Appliance Question Here...
George-Allsorts is online now

Lg f1403ld washer.dryer .No heat on dryer cycle no error codes

Customer Question

Lg f1403ld washer.dryer .No heat on dryer cycle no error codes Problem is that the tap-relay does not operate on the power board to provide a cct for the heater.Changed the heater element .tried a new power board .tried a new main power board cleaned out flue to heater fan .No change .in all situations the machine works normally with no alarms or error codes but there is no heat .
Submitted: 1 year ago.
Category: Appliance
Expert:  George-Allsorts replied 1 year ago.
Hello, my name is George..
First course of action if you are capable would be to check to see if there is power to the element at the time it should be being called for.
If you find that there is power at the element, then follow the output wiring to find the source of the disconnection.
If you find that there is no power to the element, then test the lead supply back to source to find the source of power depleation.
Kindly be patient whilst awaiting any responses from me as I'm not constantly available.
Customer: replied 1 year ago.
There is power to the element,it uses the same power source as the water heater which is working fine ,the only difference is that the tap relay for the water heater operates when required but the tap relay for the dryer heater does not operate to complete the circuit ,as there are no error codes and everything else operates correctly I'm guessing there is a disconnection between the two power boards on the lead that should operate the tap relay for the dryer heater .I have a diagram but it doesn't identify individual wires between the boards. As I said ,I have tried replacing both boards with new ones but neither has affected the operation in any way. I need to find out what operates the tap relay for the dryer heater . I assume if there was a sensor fault it would generate an error code but no errors are displayed so the machine presumably thinks everything is ok
Expert:  George-Allsorts replied 1 year ago.
Have you tried the thermostat on the side of the heater box?
Customer: replied 1 year ago.
I have proved the heater works in situ by taking power from the water heater relay to the dryer heater so the thermostat has continuity .Everything points at the dryer heater relay not operating .Do you have a diagram which shows what circuit operates when the dryer control is operated .Unless cold tumble is selected it must be meant to operate the dryer heater tap relay on the power board by some route.
Expert:  George-Allsorts replied 1 year ago.
Taking power from somewhere else bypasses the ability to test where the fault is coming from. You need to get a multimeter and test the continuity of the thermostat.. Also test its resistance. I am away today but will come back to you on my return.
Customer: replied 1 year ago.
The dryer heater still had the thermostat in the circuit I merely applied power at the plug which fits onto the tap relay on the power board so the circuit was completed through the heater and through the thermostat proving that if the tap relay operated the heater would work
Expert:  George-Allsorts replied 1 year ago.
What power did you apply to the relay at what pin?
Customer: replied 1 year ago.
I plugged the lead onto the relay for the water heater and turned on the machine so it thought it was heating water and the element heated up. I have used a multi-meter to test continuity of all the wires in the heater circuits so need to know which specific circuit components and wiring route should cause the dryer relay to operate. As far as I can ascertain the problem is lack of power to operate the relay, not power to the heater element
Expert:  George-Allsorts replied 1 year ago.
I will try get a wiring diagram tomorrow
Customer: replied 1 year ago.
Expert:  George-Allsorts replied 1 year ago.
Sorry, been away for most of the day...
There is no available diagram for the PCB, so what you are looking for is not available...
The response from LG is to change the board
Having said that, if you can post an image of your board and indicate the relay you have been initiating, I can try assist by telling you which components I can see on that board that can possibly cause the problem and therefore to test/change.
Customer: replied 1 year ago.
As I previously said I have changed both power boards for new ones and had change in performance so it isn't any component on either board but must be a signal getting lost due to a broken connection or a sensor that is not sending a message for heat but is not monitored . The dryer switch/dial must have leads that initiate the heater request .Every function on the dryer switch seems to work apart from starting the heater, everything times ok and even if I run through the test cycle it thinks everything is ok although the heater gets no power so the heat request must be getting lost or the dryer switch isn't asking for heat so I need to know how the heat request originates
Expert:  George-Allsorts replied 1 year ago.
The request is made via the program in the board and the sensors are used to detect the heat changes in the tub and the heater box..
If as you say, you have checked all sensors and wiring but also changed the PCBs then the only summission I can make is that one or more of the sensors you are testing is outside of the allowed range.. this would cause the PCB to not recognise the sensors request for heat