Tank heating pad wiring

[jking1224]

A question. I have 2017 Escape 21C. I have the tank heat pad option (and the underbody spray foam, of course).
I single page data sheet I received from Escape in the owners packet indicates the heat pads being used can be wired for AC power as well as DC power.
During orientation, I recall being told to only use the heat pads “when hooked up to AC/shore power”.
I see a 20amp fuse in the DC fuse panel. I do not see any AC circuit breaker that mentions the heat pads. This would imply the pads are wired DC only.
The advice to use them only when plugged to AC power would imply they are wired to AC as well.
The advice to use them only when hooked to shore could mean that they use a lot of power, so only use when AC power is available to charge the batteries, not clear whether they use AC direct or DC through the fuse.

The question is:
Are the tank heat pads wired as DC only or as both AC and DC?

[rubicon327]

Escape may have used dual voltage pads that have both AC and DC leads but they wire them DC only through a fuse on the DC side of the power center as you have identified. The recommendation to use them only when plugged into shore power has to do with your correct assertion that the pads use quite a bit of power and can quickly drain the typical battery bank if not plugged into shore power with the converter/charger to charge batteries. Obviously with adequate solar and large battery banks there might be an exception but I'm speaking of the average user with a base Escape setup. Explained well in this recent post:
https://www.escapeforum.org/forums/f...tml#post366024

[jking1224]

Thanks for the answer and the link to the prior discussion, which I did not find on my own.

So, for future readers of this thread:

The heat pads for the fresh tank and grey tank come from the pads supplier with wiring for both AC and DC power. They are 100 watts for each tank, for a total of 200 watts of power consumption. Escape does not use the 120v AC power leads when they install them. Escape only uses the 12V DC power wiring option on the pads.

If you go under and cut the foam insulation, you will find the 120V AC wire leads not connected to anything. This is normal and how Escape installs the pads.

The recommendation from Escape to only use the pads when hooked to AC/shore power is ONLY a recommendation due to the high DC power consumption. It is NOT because the pads are wired to use AC power. If you have an after market battery bank or lithium option or some other DIY battery bank enhancement, you may well have sufficient power to use the heat pads when not plugged into AC/shore power. The pads will use up to 200w / 15amps (approx) of DC power when both pads are cold enough to thermostatically trigger. If the weather and contents of your tanks dictate, only one pad may consume power, or neither. And only for the period it takes warm the tank contents.

It seems that Escape has used either one switch to control both pads or two switches (one for each pad/tank) over the years. I have a 2017 model with one switch. It seems later years have two switches.

If you are troubleshooting current/ohms, you must keep in mind that the pads are thermostatically operated. That means they will not “turn on” or consume power if the pad itself is not cold enough. The exact set point of that trigger is not clear. I see some discussion that it might be 45 degrees, I think the data sheet I have says it is 34 degrees. Keep in mind, this would be the temperature of the tank surface, filled with water, covered in foam insulation. Not just the open air temperature.

[rubicon327]

Great summary.