Watertech presscontrol relay on pc board only getting 12 volts should be 24v. Relay tests ok. Red fault light on.

F15 means : signal lost between oven relay board & EOC(main computer board)

1. Test the harness and connections from EOC connector P16 to oven relay board J2.
2. Replace the oven relay board.
3. Replace the EOC.1. Test the harness and connections from EOC connector P16 to oven relay board J2.
2. Replace the oven relay board.
3. Replace the EOC.

Hope this help. good luck to you.

You probably have a stuck relay. You can try tapping with medium force next to where the low voltage wires are attached to the unit using the handle end of a hammer. Even if this works it's time to replace the circuit board. Take the unit to a local vacuum repair center for service.

No, there is only two possibilities. One, the low voltage wires are touching somewhere in the system or two, the relay is stuck in the on position. To find out which it is disconnect the low voltage wire from the unit (theres two clips on the side) and then plug the canister in. If the it still runs with the wire disconnected then it is the relay board. If it doesn't then it is the low voltage wiring in the system. Good luck!

searched for and found my wiring sketch but thankyou for asking

Please clarify that we are talking about the central vac LED/switch panel panel and plugging it into a 110 V wall receptacle.
If I understand when you unplug from the power source ,then plug back in the green LED comes on, looking normal ? But when you manually activate the switch on the motor housing of the vac itself the vac does not start and the LED goes out, so no green or red LED at that point?
If this is the case , Kenmore CV's built approx 5 years ago (MADE by EUREKA) and prior had a circuit board with attached cord (as opposed to detachable) which was prone to relay failure. There were several symptoms, most common was that the relay on that switch panel /circuit board would fuse on and the vac would continue to run when the hose was detached from the wall.However some I worked on from that era had exactly the same symptom you describe. If your unit is between 5 and 10 years old and this sounds accurate, you can unscrew this curved side panel relay with one philips screw. Inside on the PCB will be an L shaped black or white 24volt relay, generally rated at 10 amps. The replacement board or relay will be rated at least 24V/ 15 amps or more. If you can isolate your motor and test it separtely with a power cord or meter , the realy/board will be the only control componnet left.
If you have a small tipped soldering IRON, not a gun, you can generally find a replacement relay to rebuild the board for about $6 at an electronics parts store. Otherwise you will need to replace the control board itself, anywhere form $45 to $70 plus service call if you have a tech come out to the house, and the tech will just unscrew , detach wires and replace the board, no repair , approx 15 minutes work. This will likely cost over $100.
Please post back with your results

The motor can only be switched on this way for 2 reasons. The circuit board inside the canister is bad or somewhere in the wiring in the house or in an outlet, a connection has been made in the low volt wiring, triggering the relay on the circuit board. If you unplug the low volt wiring from the canister and the problem goes away, then the problem is in the house, if the vac still turns on when the low volt wiring is disconnected then the problem is the circuit board inside the vac.

No schematic found. The Q1 transistor is a 2N3904, D3 was replaced with a 1N4000 series.
Root cause still Unknown, but Q1 is an exact match and D3 is an acceptible replacement.
Hoovers solution is to replace the whole PCB no matter whats wrong with it, what a waste or good technology!

Vacuum works with the battery but does not work with 120 volt. Every time I plug it in it blows the internal fuse. I have replaced the fuse inside the vaccum several times and every time i plug it in it blows. What do you think it could be?

If the top comes off, it will be by the motor and exhaust. Just replace it with the new one, make sure you don't mix up any wires. Also unplug it from the AC first.

Probably just didn't wire the l/v side of the relay properly. Or forgot to plug the leads from the outlets back in to the vac after you got it all hooked back up. Folks do it to me all the time and then make like it's my fault! Ha ha.

Jump the l/v contacts inside the CV. If it goes: trace outward toward the outlets to see if something shook loose while it was apart. If you can't jump the l/v with a plier/screwdriver at the CV or even inside it, you have an issue on the board (either how you've connected to it or it's defective itself). The prob is that there's dozens of diff board configs, plus the relays and transformers weren't together on the same board in the old days. If you've got one of these models with a massive transformer separate from the relays get out the test leads and make sure you've got adequate voltage coming out of her to power the relay coil.