Monitor M441 - Fires up - goes out...

[Linneus]

I wasn't working on the heater today. Jack, the neighbor was, the problems seemed to be getting worse as the day went on. It went from overheating to the fan running all the time, then the switches on the panel wouldn't work. No blown fuses though. Jack swore he never changed any wires. This manual has nothing on flame sensor bypass. Where is the information located, got a page number?

[HayZee518]

go to any radio shack and get a diode that wil pass 1/2 amp plus a 100K resistor. wire the diode in series with the resistor. put a couple of jumper wires on the resistor and diode with alligator clips. one end will be positive one negative. try the bypass. if it don't work reverse the leads. the resistor/diode will simulate a good flame detector.

[Linneus]

On this site there was a thread that had photos of a monitor being taken apart for maintenance. I thought I saved the information but a search of the threads revealed nothing. Any idea which thread it was?

[Linneus]

You were right Tom, I have the electrical working fine now except the fan comes on when the heater gets electricity to it. Jack, the neighbor, said he put everything back the way it was but I suspect he forgot something or switched things around. Anyway, I looked at the diagram in the service manual but can't see how this part is wired, it never explains where the wires go from the board to the sensors. Anyone have a diagram or a photo?

[hawkins111]

improper wiring

Linneus,

The white with blue wires go to the two overheat sensors on the front of the baffle. They connect to the J connector on the main board. The fan thermostat wires are white with red. They are on top of the baffle and are connected to the C connector. The overheat switches are NC (normally closed). With the wires off the sensor they should show continuity with your OHM meter. The fan thermostat switch is NO (normally open). It should show open with your meter (wires off). If you are having trouble with the flame sensor bypass, go to your Monitor or Toyostove dealer and have him set you up. Without a bypass you have to trouble shoot the unit the hard way. If you don’t have any experience with the Monitors the hard way is very much the long way. Get a by pass and run the unit with the fuel pump disconnected or the line off the burner. You can check all functions of the heater this way, it’s the easy way.

Tom

[Linneus]

I'm working on the thing now. Seems Jack did have the things wired wrong. The red/white is now going to the C connector and the overheat are on the J connector. He had one of each going to the pump, K connector. My question now is which prongs does the K connector get pushed onto? There are three. Two on the top and one down lower. This was probably why there was no juice to the solenoid. Anyway, wired as you explained, the fan still comes on. There is a jumper wire from one sensor to the other on the overheat sensors, is this right? I think I will keep my neighbor away from the heater.

[HayZee518]

while its nice and neighborly to trust your neighbor, if he doesn't really know what he's doing KEEP HIM AWAY! He may be a danger to everybody else besides himself. Monitors are very forgiving but when they don't work because someone forgot a wire they don't forgive. the combustion fan runs all the time. the circulator fan comes on AFTER the plenum temperature gets to a certain point. the ignition sequence is: Power ON, Set point SET, Combustion blower ON, Air proving switch MADE UP [contacts CLOSED], Combustion pot igniter ON, - after PURGE fuel pump ON, Fuel ignites - flame rod changes state and produces a DC current to its lockout circuitry. When plenum temp goes up, plenum switches close starting circulating fan. Then the computer takes over and shifts the fuel pump into high or low depending on setpoint, also kicks the circulator fan into high or idle.

[Linneus]

So why would the fan, (normally comes on when the heater signals it to blow the heat out the front) come on when the heater is plugged in? I can't understand the electric schematics in the service manuals. I am about the furthest thing from an electrician as far as mechanic ability goes so I too don't really know what I am doing.

Right now I need to know where things plug in correctly and I will try testing from there. I don't want to hurt the computer board.

[hawkins111]

fan thermostat wires

Linneus,

One of the B/W wires on the J connector goes to the Air safety switch and one goes to the overheat switches. As you can see from the picture of the Air safety the outside prongs are used. It does not matter which of the two you connect the wires to, but they have to be the outside prongs. The other B/W wire goes from the J connector to the overheat switch.

After you get this correct go to the C connector and disconnect it from the main circuit board. Plug the stove in, the circulating fan should not come on. Now plug in the C connector, the fan should not come on now either. If this is not the case, there is a possibility you changed the switches around. The over heat switches are normally closed and the fan thermostat switch is normally open. They look just about the same, but are completely different parts. Messing with the wiring on a Monitor can be a $450 mistake. Be very careful around electricity if you have no experience. Be very aware one of the fan thermostat wires is HOT as soon as the stove is plugged in and you can get a real hit off it. Been there, got the Tee shirt.

Tom

[Linneus]

Linneus,

One of the B/W wires on the J connector goes to the Air safety switch and one goes to the overheat switches. As you can see from the picture of the Air safety the outside prongs are used. It does not matter which of the two you connect the wires to, but they have to be the outside prongs. The other B/W wire goes from the J connector to the overheat switch.

After you get this correct go to the C connector and disconnect it from the main circuit board. Plug the stove in, the circulating fan should not come on. Now plug in the C connector, the fan should not come on now either. If this is not the case, there is a possibility you changed the switches around. The over heat switches are normally closed and the fan thermostat switch is normally open. They look just about the same, but are completely different parts. Messing with the wiring on a Monitor can be a $450 mistake. Be very careful around electricity if you have no experience. Be very aware one of the fan thermostat wires is HOT as soon as the stove is plugged in and you can get a real hit off it. Been there, got the Tee shirt.

Tom

I don't do anything while the power is on to the unit.

Sorry to be such a dim wit but one of the blue/white wires from the j connector goes to the Air Safety switch, got it. I still have two blue/white wires, one from each of the overheat sensors, I have one going to the J connector but where does the other one go, or is there only one?

And another question... Where do the two wires on the K connector go? These are yellow-coated wires. One was going to the air safety switch. You don't know how helpful you have already been! Do you have a picture of your unit wiring?

[hawkins111]

improper wiring

Linneus,

The two yellow wires go from the K connector to the fuel pump. It does not matter which side you put them on. That will free up another prong on the air safety switch. That will be the other B/W wire. Boy, I hope you haven’t fried the pump. It is very fragile. With all these wires in the right spot your stove should run OK. I hope we’re not back to the yellow flame again. If so, it is a must to get the by pass and figure out if its fuel or flame sensor.

Stay with it,

Tom

[Linneus]

Wow! Thanks for your help. I got the unit running through the cycles, no fan running. Jack switched the switches and I took them off and read the tiny part numbers on them, two of one and one left for the fan. That's working fine now too.

Unit cycled, pump pumped fuel, unit fired up but only on one side and there seemed to be a yellow flame under the right side of the viewing window that I never saw before (probably by the rod). Unit shut off as it did when I started this but if it's the overheat sensors I can find nothing blocking or coating anything. I am wondering now if the rod is touching something. Jack worked on that too...

[HayZee518]

if "nimble fingers" switched wires on you I wouldn't put it past him. the burner ring sits in the center of the combustion pot on three projections out from the inside of the pot. if the burner ring is warped badly it could be touching the flamerod. the flamerod should be centered in the gap between the burner ring and the sidewall of the chamber. you can move the flamerod slightly by loosening one screw while tightening the other one and vice versa. a sooty buildup may short out the flamerod. take it out and use gumout to clean it. a little sanding with 600 griit sandpaper wouldn't hurt.

[Linneus]

My thanks for all the help guys. I got new gaskets and a new flame rod with gasket today in the mail. (thanks to Perfect Plumbing and Heating) Only took an hour to replace gaskets and put in the new flame rod. Fired right up and had no fuel smell. I still have not replaced the O-rings on the exhaust but that will be a job for the summer as long as I detect no fuel smell.

The House is WARM once again!

Thanks for the information and encouragement.