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Model Number: Dv5451aew
Brand: Samsung
Age: 6-10 years
I replaced the coil and thermal
Sensor on the blower. Still no heat. I ordered the 2 sensors for the coil. How do I know if they are bad? If those are fine can I override them to test without damaging the brain box?
Do you have the wiring diagram?
I am not sure what you are calling sensors.
Just using a parts breakdown.
The blower has a thermal fuse which should be 0 ohms and a thermistor which is a sensor. It changes resistance with temperature.
They are usually 10,000 ohms at room temperature but I cannot be sure about this particular thermistor.
The heater has a thermal fuse which should be 0 ohms and a thermostat.
I think the thermostat is probably being used as a hi-limit. It also should be 0 ohms.
How do I know if they are bad?
Use a meter.
If those are fine can I override them to test without damaging the brain box?
I would not recommend this as you are dealing with 240 volts and a high current. 240 volts is lethal!!!
Also the thermistor cannot be shorted out as this may damage the control board.
Have you checked the power?
The heater requires the full 240 volts.
Try flipping the breaker off/on slowly, sometimes you can loose half the line without actually tripping the breaker.
If this does nothing, check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Be careful as 240 volts is lethal !!!
If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.
4. When you start always short the meter leads together. This will tell you that the meter is working and if there is any 0 offset.
I have now replaced the coil, the 2 sensors on the coil box and the sensor on the blower. It started up and had heat, thrn quit. I am ready shoot this piece of junk.
There is power because the motor turns and it starts and stops. Really the only thing for me to change is the brain box now. I have a meter but I dont believe that it is the breaker as the power is on.
The motor and the control board use 120 volts but the heater uses 240 volts!!!
So having the motor running does not tell you that the power is OK.
Quote:
Originally Posted by denman
I checked the voltage, the power, the ohms readings.
The front sensor which is the high limit thermostat and it had an infinite reading, the new and old had the same exact ohm reading. I believe the new one is defective. I ordered that $30 part from here. How do I get another?
How do I get another?
I do not know, I just answer a few post.
I have now put in 3 of the upper limit tstat. What would cause them to blow out?Quote:
Originally Posted by denman
On most units the heater has a hi-limit thermostat and thermal cut-off.
The hi-limit is a cycling type thermostat.
The thermal cut-off is a thermal fuse.
So what happens is that if the heater gets too hot the hi-limit starts opening and closing to regulate the temperature.
It is just a safety device.
It's contacts are not that great so after some time they fail usually weld together.
The thermal cut-off then blows as it is an additional safety device.
So anything that causes the heater to run unregulated could cause this.
A common cause is a grounded element.
Unplug the unit and both wires at the heater.
Measure the heater, most are in the 8 to 12 ohm range.
Then measure from each side of the heater to it's case, both should be infinite ohms.
If not then the heater is grounded and should be replaced.