Thermal Snap Disk

[Tinstar]

I have a thermal snap disk in my coach that works on 12 volts but the little heater does not work. I verified the defective heater by hooking it directly to the 12 volts, bypassing the snap disk. Will these disks work on 120 volts? I am thinking of replacing the 12 volt heater with one that is 120 volts.

I know very little about them. Would they hook to the ground wire since the plugs for the connecting wire is exposed. It was hooked to the hot wire of the 12 volt system.

I have looked for a 120 volt thermal snap disk but am not able to find much information on them. Nothing comes up when I search for a 12 volt thermal snap disk. The ones I am finding cut on at very high temperatures and shut off at an even higher temp. I need to keep my water bay from freezing but not at 185 degrees. Looking for on at mid 30's and off about 40 degrees.

[JaxDad]

Tinstar wrote:

JaxDad wrote:
Since you're already looking for a 120 volt heater why not just get the proper $20 heater instead of trying to reinvent the wheel.

I'm not sure what you mean "the proper heater". I have the 120 volt heater/s which I am using.

From your original post;

Tinstar wrote:
I am thinking of replacing the 12 volt heater with one that is 120 volts.

[Tinstar]

JaxDad wrote:
Since you're already looking for a 120 volt heater why not just get the proper $20 heater instead of trying to reinvent the wheel.

I'm not sure what you mean "the proper heater". I have the 120 volt heater/s which I am using. I may put a good 12 volt heater in for travel, IF I can find a good one.

[Tinstar]

A little explanation is in order. It's not an Aqua Hot. I keep my coach in my RV shed at home when not camping. I don't like to blow out my lines after every trip so I just want to keep the temperature in my wet bay above freezing while parked at home. I do have a couple of thermo cubes and am using them with my little 120 volt space heater. Presently I am running a dedicated 30 amp extension cord, from my shed, into my wet bay. My coach is plugged into a separate dedicated 50 amp line.

When deciding to run 120 volt heater instead of the 12 volt, I discovered I don't have a shore powered 120 volt outlet in any of my bays. The one that is there is running on the inverter (that seems unusual to me). I didn't think it would be a good idea to run the heater off the inverter and that's why I ran the 30 amp line into the wet bay. I know I don't need anything that big for the little space heater but it was what I had and am not using the 30 amp for anything anyway.

Now, to the point. I was thinking about wiring a 120 volt outlet (from the 50 amp coach power panel) into the area. Then wire the snap disk into the heater cord. That way I don't have to mess with the extra extension cord every time the temperature gets too cold. If I find a good 12 volt wet bay heater, I may eventually wire it back up. The one that isn't working is the "Back Seat Heater" and they get terrible reviews. Suggestions for a good one are welcome. BTW, I know I have power to the 12 volt line and I believe the snap disk is working fine. Just in case, I did buy another disk yesterday (thanks time2roll for the link). Apparently the snap disk don't care if it's 12 or 120 volts.

Just FYI, the 120 volt heater information. I have three 200 watt space heaters and two 250 watt space heaters. I think one will be enough for the wet bay and I didn't buy that many just for this project.

[bluwtr49]

TinStar, are you by any chance talking about the bay heater on an AquaHot system???

[Matt_Colie]

Did you try re-setting the Snap-Disk? You may have to push on the disk or there may be a button on the back side. They are usually re-settable.

Or, you could replace it with a thermal fuse for the right temperature and current.

Matt

[DSDP_Don]

"Tinstar".....The heater cube and snap disk in your coach was designed to be used while boon docking, that's why it's 12 volt. Since you're talking about using 120 volts as a heater supply, you could just put a simple heater in the space/bay or not worry about it at all.

If you're looking to heat the bay while in storage, the 120 volt heater will work. If you're looking to keep it warm while camping with shore power, I think you'll find the use of your heaters inside the coach will keep the wet bay from freezing, unless you plan extended camping in weather below 20 degrees.

When I had my Diplomat, I carried a trouble light with a 100 watt bulb with me. On the rare occasion where the temps might be in the teens, I placed the trouble light in the bay. You don't say if you're looking for something for long term use, but a trouble light plugged into a wall timer would probably solve your issue.

[crasster]

You can also look the specs and model numbers of the thermal disk itself and order one from China for pennies. May take 3 weeks to come in but I've done this several times. A good idea is to order 3 or 4 and keep them.

A bit of solder and you are good to go.

[tommy_g]

Old-Biscuit wrote:
12V DC and 120V AC devices are NOT interchangeable


Thermal Cube
TC2 or TC 3

The TC3 Thermo Cube is the perfect thing for this. It's on at 35deg and off at 45deg. I use a 100w bulb in my utility bay and also a 60w in my frig access area.

[JaxDad]

Every one of those little cube heaters, and most ceramic type heaters have a feature they call 'frost guard'.

Basically the temperature adjustment won't let you turn it colder than about 35 or 40 degrees.

Since you're already looking for a 120 volt heater why not just get the proper $20 heater instead of trying to reinvent the wheel.

[Ivylog]

The Monaco's higher up the food change use an adjustable Tstat like ......this for $55. I would use it but you need to set the temp that you want the bay heat on before installing as the degrees may not be marked on the dial. Yes the snap disk would work on 120V as it is nothing but a on/off switch that cannot tell the difference in 12V DC or 120V AC.
By switching to AC you will have to run the generator if driving in below freezing weather. I would test the snap disk by putting it in the freezer to make sure it will close.

[Moondaddy]

You can purchase a ready made thermal control that plugs into 120 volt outlet then plug your shop light or heat source into that. Have used them to keep water free of ice. Old-Biscuit has one type that looks good, the one that I use is a single plug and larger. Have used w/ heat lamps but not radiant heaters.

[time2roll]

Plenty of 120 volt options at about any temperature.

I have used these: http://senasys.com/products/thermostats-sealed/2511-options

Lots of different mounting options in addition to temperature. Search around the site for what you need.

[Old-Biscuit]

12V DC and 120V AC devices are NOT interchangeable


Thermal Cube
TC2 or TC 3