Restoration & upgrade of 1960s Markel Heetaire space heater

[iroc86]

Here's the schematic for the fan controller board. There's obviously more going on here than in the original design, but I made a few changes to help with safety, reliability, and performance.

- Added internal 15 A circuit breaker CB1.

- Added earth grounding to chassis.

- Changed from daisy-chain wiring to discrete terminal blocks for line and neutral.

- Changed arrangement of thermostat SW1 and control switch SW2. This will now switch only the hot side.

- Added neon indicator DS1.

- Added fused triac driver with adjustable phase control.

- Added relay control for "high" heater element. The reason is twofold: 1) try to eliminate some contact arcing on the vintage, irreplaceable SW2, and 2) by tapping the relay coil after F1, disable the "high" element if the fan driver somehow fails in an overcurrent situation. This ensures that the "high" element won't come on without the fan, preventing overheating.

- Added EMI line filter. This probably isn't necessary due to the simplicity of the circuit, but I figured it wouldn't hurt to reduce noise from a triac chopper sitting on the mains.

[kanuk]

Look for this white tape on motor. Are you sure its  not asbestos? 

[kanuk]

 I forgot about wires....

[iroc86]

Ha, my post is back from the dead.

kanuk, it wouldn't surprise me if the tape and insulation contained asbestos. I have two of these heaters, one from 1967 and another from 1972, so it's fair game. Another reason to refurbish, I suppose. FWIW, I ended up finishing the heater last year. I stopped posting updates once this thread, umm, devolved after having to defend my reasons for replacing all of the old bits.

I'm actually in the process of rebuilding another one. If anyone's interested, I can share some pictures.

[kanuk]

Hi Dear,  I find solution for you.. some protection