Turning the
Chromalox Heater On and Off
There is a space
heater mounted on the garage ceiling over the workbench. It was
installed by Anne's Grandfather, probably when the house was built in
the 1970's. No instructions were available.
I was able to turn
the heater on, but could not immediately figure out how to turn it
off again. We eventually found the fuses that controlled the heater
and turned it off at the fuse box. Fortunately no important parts of
the house were affected by this. After a week, I finally got it to
turn off.
I could find nothing online about this space heater or its controller, so here's my solution--
Here are the
markings on the equipment;
Heater element
and case:
Canadian Chromalox
Company
R: 73
240 Volts, 2000
Watts
Cat No. CRT-4320
Controller/Switch
Probably a “VCF
Percentage Timing Input Controller.” If it is, the timer
controller energizes the heating element for a certain percentage of
the preset (30 second) heating cycle.
Markings; B, 30 Sec,
Percent
knob on front
Push button on L
side
2 pointers on dial,
one red, one black.
Circular dial scale
from 3 to 100.
Turning the
Heater On;
Turn the front knob
counter-clockwise (CCL). The black pointer carries the red pointer
clockwise (CL), from 100 to the end of the scale at “3.” This is
probably the percentage setting for the heating element.
Turn the front knob
CL all the way around, so that the black pointer crosses over the red
pointer. The box will click, and the heater turns on.
You can also press
the button on the right side of the box really hard, until it clicks.
This causes the red
pointer to rotate CL, one revolution every 30 seconds. The box
clicks once when the red pointer passes 100, and once again when it
passes the black pointer.
Probably the red
pointer is turning the heating element off and on for the percentage
of the 30-second cycle indicated by the black pointer.
Click the button on
the right side of the box again, and the red pointer stops moving.
Turning the
Heater Off;
Probably, just click
the left side button to stop the red pointer when it's between 100
and the black pointer. For safety, rotate the black pointer to “3,”
the lowest setting. Check off-ness in ½ hr.
The short version; Click the switch off when the red pointer is between 100 and the black pointer. If the red pointer stops in this 'cycle-off' zone, the heating element is disconnected and will cool down.
ReplyDeleteIf you click to stop the red pointer between the black pointer and zero, you halt it in the 'cycle-on' zone. The heating element then remains connected all the time, and you could possibly set something on fire.
Beats me why there is no safety off switch, but I guess that's how they made all-electric homes in the 1970's :-)