Samsung DV42H5200EW/A3 NO HEAT! Stumped!

[Scoper50]

Model Number:
Brand: Brand
Age: Less than 1 year

Model Number: DV42H5200EW/A3
Brand: Samsung
Age: 1-5 years

So I have this Samsung dryer, about 4 years old now. Yesterday it stopped producing heat. I'm an auto mechanic so I'm pretty handy with tools and knowledgeable about electricity so I decided to tackle this myself. Upon doing my initial research I found the usual suspects are the heating element, the hi limit switch, or the thermo cutoff located on the heater housing. I ohm'd everything out. I have 9.5ohms across the heating element, and 1ohm on both the hi limit and cutoff switches. Everything appears normal. I checked the heater relay on the control panel. I'm getting 120v on both terminals with the dryer running. No problems here. I checked voltage at the heater element with the dryer running. I measured 120v at both terminals. I'm not understanding how I can have voltage running through the heating coil yet it doesn't heat up. I have checked it to make sure it's not shorted to ground.

Here is the kicker. The dryer has a "smart install" mode that can check the touch sensor operation along with the motor and heater. When I run this mode by holding "adjust time up+the temp key for 7 seconds, the dryer goes into the test mode. The drum spins and it will produce heat for roughy 10 seconds. Then it indicates on the display that the system is ok. So I know the thing is capable of producing heat. It just won't do it in it's regular cycle. I have also checked both thermostats on the blower housing for continuity. Both come out at 1ohm. I'm stumped. The only thing I haven't checked is the centrifugal switch. That would require removing he entire drum for access. Anyone have any advice? I thought this might be something simple.

[denman]

I'm getting 120v on both terminals with the dryer running
This does not really tell you anything.
With the dryer running.
If the relay closes you will see 120 and all is good re: L1
If the relay does not close then you will also see 120 on the input side re: L1 but also see 120 on the output side re: L2

This also applies to the heater.
So lets say only L1 is OK then you see 120 on both sides of the heater but they are both L1 so across the heater itself you have 0 volts.
If all is OK then you also see 120 on each side of the heater but now is is L1 and L2.
Since these two are 180 degrees out of phase one iis at paositive 120 volts while the other is at negative 120 volts so across the heater you have 240 volts.


Have you checked the thermistor resistance?

Since you get heat is a test mode the 240 is probably OK but it would not hurt to double check it.
This also applies to the motor's centrifugal switch.

Sounds like the control board is no good.

[Scoper50]

I did some more trouble shooting last night. I tore the dryer down all the way so I could access the centrifugal switch on the motor. It checked out good. So I decided to do some more running tests. (after reassembly) I noticed that when the heater was unplugged I was getting 120 on the leg coming from the centrifugal switch but I was getting zero on the other end coming from the heater relay. So I took the terminals out of the heater relay connector, taped them together and the heater fired right up. It's a bad heater relay which means I'm getting a new control board.

[Bjbarrachus]

I did some more trouble shooting last night. I tore the dryer down all the way so I could access the centrifugal switch on the motor. It checked out good. So I decided to do some more running tests. (after reassembly) I noticed that when the heater was unplugged I was getting 120 on the leg coming from the centrifugal switch but I was getting zero on the other end coming from the heater relay. So I took the terminals out of the heater relay connector, taped them together and the heater fired right up. It's a bad heater relay which means I'm getting a new control board.

I am having the same problem. I have made sure sir circulation is good. I have tested and replaced thermistor, thermal fuse, and control board. I tested the heating element and the control switch. I tested the voltage. It says 113 for each leg. When doing the test, it also results in heat and an OK on the screen, yet, when I run the dryer, it doesnt heat. I have basically replaced everything but the motor. What am I missing? It heats during the test, so it cant ve the heating element. Someone please help. I'm going on a month without a dryer and very frustrated. I refuse to call a service tech because it doesnt eeek yo help anyone fix the problem. I really hope someone has an answer. I dont want to buy a new dryer after replacing my back door and getting a new roof, I'm kind of broke.

[Scoper50]

I am pleased to say that I fixed my dryer, although I forgot to update this forum so I'll do that now. As I said in my last post i purchased a new control board. Guess what, it DID NOT fix the problem. It turns out my centrifugal switch was bad and I was was testing it incorrectly. I bought a new motor for $80 which contains the centrifugal switch and all is good. Out of curiosity I took apart the old centrifugal switch and sure enough one of the contacts inside had broken clean off.