T
[email protected]
- Jan 1, 1970
- 0
Few days ago my propane RV refrigerator died, again.
Desperation often promotes inventiveness. In the garage I have a 19 cu. ft.
upright freezer, and I rigged an industrial, remote-sensing thermostat to
control its input power, the sensing bulb mounted in the top of the freezer
box. Since I need about half of its volume, I filled the bottom with taped-
up cardboard boxes, reducing the amount of air exchange when the door is
opened. The top shelf is mostly filled with beer and soda to give lots
of thermal mass. Performance looks really good - data tomorrow - Brand
wattmeter is recording now.
My only concern so far is about the automatic defrost feature. Every 10
hours of compressor run-time, a 500 W heater is switched on for 21 min.
There is a thermal switch in the heater power feed, cut-in 20 deg., cut-
out 50 deg. Since freezers can operate well below zero, it's likely that
the coil and its discharge air get cold enough to frost the coil, and close
the thermal switch. So far I've seen no evidence of a defrost event or
water in the condensate pan.
I'd like to eliminate the power drain from the automatic coil-defrost. Box
internal temp. range currently is 38 to 41 deg. This morning's dew point is
30 deg., fairly typical this time of year (much lower in winter). Do you
think if I can make the evaporator fan run some time (how much?) after
compressor shuts off, the coil would be defrosted? How can I tell if the
coil is being kept clear of frost, and how tell if it frosts up?
So-far data: 60 watt-hours consumption in 2 hours measurement, 60 to 70 deg.
ambient. Today is predicted to reach the mid-90's, a good data day!
Tom Willmon
Mountainair, (mid) New Mexico, USA
Buddist at McDonald's, "Make me one with everything." - Moose Tomson
Net-Tamer V 1.12.0 - Registered
Desperation often promotes inventiveness. In the garage I have a 19 cu. ft.
upright freezer, and I rigged an industrial, remote-sensing thermostat to
control its input power, the sensing bulb mounted in the top of the freezer
box. Since I need about half of its volume, I filled the bottom with taped-
up cardboard boxes, reducing the amount of air exchange when the door is
opened. The top shelf is mostly filled with beer and soda to give lots
of thermal mass. Performance looks really good - data tomorrow - Brand
wattmeter is recording now.
My only concern so far is about the automatic defrost feature. Every 10
hours of compressor run-time, a 500 W heater is switched on for 21 min.
There is a thermal switch in the heater power feed, cut-in 20 deg., cut-
out 50 deg. Since freezers can operate well below zero, it's likely that
the coil and its discharge air get cold enough to frost the coil, and close
the thermal switch. So far I've seen no evidence of a defrost event or
water in the condensate pan.
I'd like to eliminate the power drain from the automatic coil-defrost. Box
internal temp. range currently is 38 to 41 deg. This morning's dew point is
30 deg., fairly typical this time of year (much lower in winter). Do you
think if I can make the evaporator fan run some time (how much?) after
compressor shuts off, the coil would be defrosted? How can I tell if the
coil is being kept clear of frost, and how tell if it frosts up?
So-far data: 60 watt-hours consumption in 2 hours measurement, 60 to 70 deg.
ambient. Today is predicted to reach the mid-90's, a good data day!
Tom Willmon
Mountainair, (mid) New Mexico, USA
Buddist at McDonald's, "Make me one with everything." - Moose Tomson
Net-Tamer V 1.12.0 - Registered
