FIXED Maytag MEDB850YW electric dryer heater relay has 0V between red and black when running, and has no heat

[chasbirder]

Model Number

MEDB850YW

Brand

Maytag

Age

6-10 years

MEDB850YW Maytag Bravos XL dryer stopped heating three days ago. Running diagnostics showed an F4E4 code, and install diagnostics was L2. I confirmed the circuit breaker was 240, and the outlet was 240. I ran without any vent hooked up and still no heat. I then followed the service technician instructions for CCU power tests and everything was correct. (Attached the tech sheet so you can see what I was following).

I found this thread

FIXED - MED7000AW0 Maytag dryer has no heat

Hi, I have a Maytag MED7000AW0 that is not producing any heat. The dryer spins and everything else appear to work normally. Using the diagnostic mode, I get an error of F4E4, and sometimes when running a load a see an error of L2 flash on the display. Here's what I've checked so far: -...

www.applianceblog.com

It seemed to make sense, so I tested the heater relay as well. The black L1 from the heater relay had 120 V to P8-3 when off, and when when running timed dry high heat, there was 120V from red to P8-3, but there was 0V between the black and red on heater relay when timed dry high heat was running.

I posted this to that old thread, but then realized it would be best to start a new thread.

It is my understanding that this means the relay is toast (right? since I know each has 120V but not 240 between them?), and I'll need to replace the board?

Big thanks to everyone.

 

[Jake]

Did you first unplug the dryer from the wall outlet and ohm test the thermal cut-off and high limit thermostat and heater? Look on page 22 at the wiring diagram where the heater relay COM goes too.

Here's your parts diagram:

Parts for Maytag MEDB850YW0: Bulkhead Parts - AppliancePartsPros.com

Parts for Maytag MEDB850YW0: Bulkhead Parts in stock and ready to ship today. 365 days to return any part.

click.linksynergy.com

#14 is the heater
#47 is the thermal cut-off
#48 is the high limit thermostat

Here's the control board for your model:
WPW10432257 Electronic Control Board


Jake

 

[chasbirder]

Thanks Jake, I hadn't gone below yet. Across the thermal cut-off and high limit thermostat and heater I am reading ~1-2 ohms (between each is the same), and as a followup, in on the CCU am reading 10 ohms between P4-3 and P4-6 (p 15) test.

I am going to be honestly ignorant and not sure what this means about what part is actually broken. Big big thanks for your help and time.

 

[Jake]

Yes, I always ohm test those parts first I posted above before I replace the control board.

Make sure your dryer is unplugged from the wall outlet first before accessing and ohm testing those parts.

Jake

 

[chasbirder]

Right, that board is pricey for sure.

So it was unplugged when I ohm tested. Based on low ohms across them all, what is the prognosis?

 

[chasbirder]

Pretty sure 1 ohm across all three means they are electrically open, right? Which according to the manual (from page 14 first post, and below) this means I need to replace the heating element but everything else is good? Just need to know since I’m going to order them and then leave town for a few days and need to fix it when I return.

Again, thank you.

 

[Jake]

Lets make sure you are ohm testing properly:

For the thermal fuse and the thermostats: https://www.repairclinic.com/Repair...Dryer-Not-Heating-Thermal-Fuse-Testing-Repair

For the heating element: https://www.repairclinic.com/Repair...ating-Heating-Element-Testing-Troubleshooting

Jake

 

[chasbirder]

Thanks for your patience Jack. I didn’t know you calibrate the miltimeter first. Anyways, unhooking then testing heater fuse and thermostat, both read 0 ohms. Unhooking and testing heating element it doesn’t read anything. So heating element is bad?

 

[Jake]

Unhooking and testing heating element it doesn’t read anything. So heating element is bad?

You nailed it!

Dryer Heating Element WP8544771


Let us know how it goes!

Jake

 

[chasbirder]

Thanks! It’ll be late this weekend before I am back and install part, but I’ll update.

 

[Jake]

Ok sounds good, yes keep us posted.

Jake

 

[chasbirder]

Replaced the heating element Sunday night, and checked resistance everywhere again before re-assembling, and it looked good. Turned it on and the dryer was heating again!

HUGE thanks Jake! Really, thank you.

 

[Jake]

Excellent, glad to hear the new heating element fixed it.

Thanks for the update!

Jake