How to test Heating Pads

[dswood1]

Colorado had an unusual cold snap, down to 30 degrees after reaching almost 100 on Sunday/Monday. I have a 2016 Coachmen Prism class C with heated black and grey tanks, and wanted to test them before the cold hit, as we're not ready to winterize yet!

Since they are thermostatically controlled and do not turn on (even if switch is on) until they drop below 44 degrees, is there a way to test them?

Also, I've never had heated tanks before, and I am curious what I should feel...when the cold came in yesterday, I checked them regularly and could indeed feel a bit of warmth, but barely anything. Are they hotter on the tank (sticky) side that is against the tank? The warmth I felt was almost not noticeable, so I'd like to know what I should feel and if they're working right.

Thank you!

[Mr_D]

As long as the tank contents are above 32° there isn't a problem. Did you check the actual temp? Non-contact temp gun is ideal for this.

[Old-Biscuit]

Ice pack held against bugle on end of heating pad where thermostat is located.

No Access to pads.........
Then you would need to dump tanks and then add LARGE quantity of ICE to tank and watch for increase in DC Load
**really tough to actually test w/o physical access to pad & thermostat

Heat is generated 'towards' tank......otherwise heat generated would be sucked up by cold air surrounding the pads

[NXR]

Originally Posted by Old-Biscuit

**really tough to actually test w/o physical access to pad & thermostat

Fasten a thermometer you don't care about to a piece of string or plastic line and drop it in the toilet for a while.

As Mr_D noted, an infrared thermometer could be of use. It might show a temperature rise on the side of the tanks between measurements.

My tank heaters want the tanks to have fluid in them, probably ten or more gallons to get the indicator up to 1/3rd. It would take some serious cold to freeze ten gallons of water to a chunk of ice. The dump lines would freeze faster and they have non-thermostatic elbow heaters turned on by the tank heater switch.

If the OP has a weather station onboard, consider moving the outdoor sensor into areas where you have water. I learned that my water pump compartment stays about 10 degrees above the outside air temp while the wet bay with the water filter only stays about 3 degrees above the outside air temp. So I use a small 250 watt electric heater connected to a Thermo Cube in the wet bay when it's getting near freezing or below. Having data is good.

Ray

[dswood1]

Many thanks for the great ideas above! Temps never went below 30, so we were all good. The pads were slightly warm to touch, so I knew that at some level they were indeed working.

Since I've been getting a closer look at them, one pad seems to be peeling a little, so I will have to address that too.

Any idea how long batteries might last with heating pads going if I were without AC? I don't have any real winter camping planned, but I will be close on some nights, and want to be prepared.

I will be traveling with antifreeze too, so can always mix it in if I am concerned. ALl water lined and fresh tank are warmed by RV interior fortunately, so my only concern is the black and grey tanks...

[NXR]

Originally Posted by dswood1

Any idea how long batteries might last with heating pads going if I were without AC? I don't have any real winter camping planned, but I will be close on some nights, and want to be prepared.

That's one of those "It depends" answers. My heating pads will not power up unless the voltage is at or above 13.2 VDC. If the voltage drops below that level the heating pads will shut off. Mine are controlled by the Precision Plex touchscreen system and they do have a manual override capability for the voltage level.

From the Therma-Heat manual, mine should pull noticeably over 20 amps total because there are heaters on each tank plus the elbows.

Ray