BN4 Temperature Switch

[ZacharyRitter]

Can anyone give some insight as to "how" to adjust the temperature switch on a BN4. The problem I am having: The bi metal spring will move up and down and rotate the inside shaft that holds the white plastic lobe while the heater is on and off. The heater will stop when warm, not hot (running time less than 1 minute) and cut completely off. I can jump the two blue wires on the switch and it would run all day or until it overheated and blew the fuse or tripped the safety switch. I don't think that the part is bad (as the spring, lobe moves and it will cut the heater off), just way out of adjustment.

[Wildthings]

When you pull the knob out (on the dash right next to the driver's door) it should change the on and off temperature setting of the thermostat. You should be able to see the cable which is hooked to the knob moving the lever in the thermostat housing. You should also be able to see the points opening and closing as the lever moves, at least if the heater is moderately warm.

[ZacharyRitter]

How do you change the plastic white "lobe" position setting if it is not making closing the contacts. It is like the lobe is "out of time" and will not turn the heater. You can manually turn the lobe with your finger and it will make contact with the points and will have heat until it gets warm and then will cut off because the bi-metal spring will shut the pump down.

[Wildthings]

You didn't answer the question as to whether the lever in the thermostat housing moves when you pull the knob on the left side of the dash. Checking this would be the first place to start.

Yes, IIRC it is possible to put the thermostat together wrong.

[ZacharyRitter]

The thermostat housing moves when you pull the knob out and in. I have attached a picture of the positioning when it is cold and the heater knob is pulled all the way out.

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[[email protected]]

You can pull the white lobe directly off and then push it back in the position that you want it
I think what you need to look at is if the actual shaft is moving when you slide it back-and-forth Not just the lobe
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[Wildthings]

It looks to me like someone messed with the adjustment of the cable maybe to try and get more heat out of the unit. I would readjust the cable so the lever travels the full distance it can and then reposition the cam as [email protected] suggests.

It is pretty easy to remove the entire thermostat from the heater so that you can inspect the whole of it.

[ZacharyRitter]

Can you provide a picture or description of what it should look like (lobe and cable position) with the cable all the way in and all the way out? How do you "test" it to make sure it is operating at the correct temperature?

[ZacharyRitter]

Update: Last night I noticed that the travel where the cable attaches was very minimum which led me further to investigate that it was only taking the slack out of the cable lock on the cylinder. So I took it apart and oiled it back where it will travel the entire distance with NO resistance or binding. So with that said the inner and outer shaft (looking from the top down) moves freely. I have placed a heat gun on the bi metal strips and they contract and turn the interior shaft as designed. So the first of a two part question: How do I test to see if the unit is moving the correct distance (bi metal springs) and the second part: I need to know how to "set" where the lobe needs to be setting and testing to make sure that it is working as intended. A complete overview would be very helpful.

[Wildthings]