Water tank heating pads

[Thumper7]

Question about the water tank heating pads. I have 3 switches for the pads, one for fresh water tank, one for black tank and another for grey tank. We are fulltiming and always keep the valve for the shower tank open and the one for the kitchen sink and black tank closed until needed to drain. Does the one switch for the grey tank, operate 2 heating pads - one for the shower and the other for the kitchen sink? I've always understood that you need some water in the tank if you're using the heating pads. Should I close the drain valve for the shower and run some water in the shower before turning on the grey tank heating pad? Hopefully some cold weather experts will be able help me out.

[retamaman]

I would close the valve during the time you need to heat the tanks. If it's cold enough to do that, your sewer hose could freeze and rupture. Better safe than sorry. I am by no means a cold weather expert, but discretion is the better part of valor.

[Thumper7]

Thanks Retamaman, that's what I've done. Just wonder why there is not separate switches for the two tanks.

[retamaman]

I think it's likely the gray tank heaters are controlled by the one switch.

[rockfordroo]

Originally Posted by retamaman

I think it's likely the gray tank heaters are controlled by the one switch.

Originally Posted by Thumper7

Thanks Retamaman, that's what I've done. Just wonder why there is not separate switches for the two tanks.

Saves them $2!

[Jestercyco]

I just this last 2 weeks down here in Texas. I have one switch for all pads. They run on 12VDC. worked very well in 15 degree temps with wind chill in the single digits. I knew about water in the 120vac on water heaters but had not heard about heat pads on grey and black tanks. Was nice to be able to drain all of the tanks when the temp was 18 on Monday in the AM.
Jester

[markb422]

Cold weather camping on our way to and from Florida from Michigan I used the heat pads but also poured a half gallon of RV antifreeze in each tank for a little extra insurance.

[PSU Turf]

If dump valve is always left open you can slowly build up, for lack of a better term, gunk in the tank. Better to fill the tank at least part way and dump every few days even if you aren't using the heating pads.

[SailorSam20500]

My pad have built in thermostats - automatically turn off if above 40 degrees. So, I'm not sure you have anything to worry about. I'm sure the plastic on the tank can survive being heated to 40.

[jgriffin7]

Originally Posted by Thumper7

I've always understood that you need some water in the tank if you're using the heating pads.

I only have one switch that operates all tanks, and my fresh water is always drained. Have I done damage? Had the rig for 3 years now....