Frost proofing with incandescent bulb

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flashlight

Senior Member
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NY, NY
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Electrician, semi-retired
So my wife finally talked me into installing dishwasher at our cabin in NW NY state. I installed it in the spring when winter was far from my mind. Like any plumbing there I built it so supply line is easily drained. But for residual water in pump I have read that I must run a rinse cycle with non-toxic (RV) antifreeze so that remains in pump.

I don't like that method for various reasons. I am considering building a shallow cabinet to mate to the front of the DW cabinet, creating an enclosed space which would be heated by one or two incandescent bulbs controlled by a thermostat such as a "thermo cube" or something higher end.

Has anyone done anything like this? I'm not sure about calculations for wattage, such as when it's 15 degrees inside the cabin.
 
gadfly56

gadfly56

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New Jersey
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Professional Engineer, Fire & Life Safety
flashlight said:
So my wife finally talked me into installing dishwasher at our cabin in NW NY state. I installed it in the spring when winter was far from my mind. Like any plumbing there I built it so supply line is easily drained. But for residual water in pump I have read that I must run a rinse cycle with non-toxic (RV) antifreeze so that remains in pump.

I don't like that method for various reasons. I am considering building a shallow cabinet to mate to the front of the DW cabinet, creating an enclosed space which would be heated by one or two incandescent bulbs controlled by a thermostat such as a "thermo cube" or something higher end.

Has anyone done anything like this? I'm not sure about calculations for wattage, such as when it's 15 degrees inside the cabin.
Click to expand...
You just need to do some basic thermo calculations to see what wattage you'd need to keep the space heated. Adding a little insulation can help a lot if you start seeing some really high numbers.
 
Srv52761

Srv52761

Senior Member
Location
lowa
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Energy Manager
I have a similar setup to store liquids in my unheated detached shed. I use an old non-working freezer. For the heat source I use an oil pan heater adhered to a cookie sheet. The thermostat is a thermocube.
Drilled a hole for an extension cord near the bottom, sealed it. Cube at the bottom heat at the top.
Liquids near the top

The cube goes on at about 38°, but it is always about 4° or more colder at the bottom than the top. So it keeps everything about 42°-50° all winter.

The oil pan heater is way overkill. I toyed with a light bulb, or rather a series of 7 watt night lights on a power strip in case one burned out on a thermocube, or a terrarium/aquarium heater as they have their own thermostat. But thought the oil pan heater would be more robust.
 
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winnie

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Location
Springfield, MA, USA
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Electric motor research
Incandescent lamps are simply cheap short life resistance heaters. I'd suggest using a slightly more expensive and more reliable resistance heater. If you want 'screw in' you can even buy ceramic heaters that will screw in just like an ordinary lamp


On the other hand, potable water antifreeze is very benign stuff. Somewhat more toxic then ethanol, you can drink small quantities and your body simply processes it. If you are concerned about it going down the septic system: the bugs in there love the stuff. It is basically propylene glycol, which your body processes to citric acid; the very similar (but much much more toxic) ethylene glycol gets processed to oxalic acid which destroys your kidneys.

Jon
 
gadfly56

gadfly56

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Location
New Jersey
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Professional Engineer, Fire & Life Safety
Maybe a little pricey, but I just though of the heaters used in Hoffman boxes when you have electronics that can't go below freezing. Go to their site (actually nVent now) and poke around. You can get a thermostat to go with it as well.
 
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flashlight

Senior Member
Location
NY, NY
Occupation
Electrician, semi-retired
Thanks everyone for info/links.

Tom, I use a lot of RV antifreeze, to protect traps. I am not concerned about it in septic but wonder about
its effect on seals/gaskets in pump
 
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Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
winnie said:
Incandescent lamps are simply cheap short life resistance heaters. I'd suggest using a slightly more expensive and more reliable resistance heater. If you want 'screw in' you can even buy ceramic heaters that will screw in just like an ordinary lamp


On the other hand, potable water antifreeze is very benign stuff. Somewhat more toxic then ethanol, you can drink small quantities and your body simply processes it. If you are concerned about it going down the septic system: the bugs in there love the stuff. It is basically propylene glycol, which your body processes to citric acid; the very similar (but much much more toxic) ethylene glycol gets processed to oxalic acid which destroys your kidneys.

Jon
Click to expand...
How about an old one...
23429873-FC73-4D61-9904-6E6B171D55E3.jpeg
 
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flashlight

Senior Member
Location
NY, NY
Occupation
Electrician, semi-retired
Wow, look at that. I guess safe enough with proper clearance...what could go wrong ? ; )

I have some crazy old stuff in my bins, too
 
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Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
flashlight said:
Wow, look at that. I guess safe enough with proper clearance...what could go wrong ? ; )

I have some crazy old stuff in my bins, too
Click to expand...
It actually works. I’ve plugged it in For a couple of hours just to see it burn up and it gets pretty hot, but keeps on going.
I wouldn’t dare leave it unattended for any reason...
 
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suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
If you use an incandescent ligt bulb, but the extra long life ones. They are typically 130V, have an orange tinge, but can last quite a long time. I used those to heat under seat of a shower because it mildews if I don't. That light only comes on when the shower fan is on. I also use five 4 watt night lite lamps in my gunsafe to keep it warm (and provide light to see what is in it). Was cheaper than buying another "goldenrod" heater which is 30W, but that is made to be a reliable heater whereas I'm always changing the little light bulbs. LED bulbs last a long time, but they don't make much heat. The goldenrod may be a good solution for a dish washer.

Does your cabin really get that cold in the winter? Does it get any sun through the windows? Does it have decent insulation? I think passive solutions may be better unless power is completely reliable there.
 
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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
From what little I've read, RV antifreeze is good for the pump seals. But IMHO flashlight is good to be concerned about this because it isn't a no-brainer.

You _don't_ want to drain out the pump; if the seals dry out then they shrink and crack, and then they _will_ leak.

-Jon
 
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flashlight

Senior Member
Location
NY, NY
Occupation
Electrician, semi-retired
Hal, I was concerned about pump seals, maybe not an issue?

Larry, when I first started as an electrician in mid eighties, an old timer showed me how to make
a tester from 2 pigtail bulbs in series. Glowed dim, 120, glowed bright, 240.

But I hadn't considered bulb life in that setup
 
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