Cold weather with enclosed heated tanks

Hi Snowman,

I've tested my system to -27 C (-16.6 f). I found out that the dash heater would prevent the furnace from running and then I'd have freezing issues. So I replaced the return air grill on the furnace with a fan. On my rv that circulates warm "living space" air under the cabinets and pushes some air along the furnace duct work. I chose to use a dual window fan unit which is controlled by a mechanical thermostat that lives beside the water pump next to the outdoor wall of the RV.

The fan unit draws just 23 watts and works better than a 1500 watt fan based heater which I tried using inside the cabinet.

Turn them on as temperature go below freezing. If not plugged in or running the house battery may drain quickly.

We spent a night in Jackpot Nevada last December 28th and it went to -30C (-22F) and the only problem we had was the water line from the fresh water tank to the water pump froze up. Turns out there was no harm done but in the future we will take additional precautions as this line runs along an outside wall in the bedroom.

Our black and grey tanks (+ gate valves) are heated by the furnace (and engine heat while in transit), no heating pads. 2004 Triple E Regency 28 foot.

On edit, I should mention that we also had the vehicle block heater plugged in all night and I am glad we did as I am unsure if it would have started in the morning at ambient temperature (Ford E450).

Hi Harvard,

If it is the venerable v-10 it will start at -30 C. But I would far rather do as you did and plug in the block heater.

Also, never (EVER) run the tank heat pads with the tanks empty.

Ok, thanks for the tips.
Sounds like I should be okay in the teens if I use the available heat.

My RV has a slightly different configuration with both the 12 volt heaters (usually on joints and elbows) and the tank heaters on 120 volt power. I have left mine plugged in and unwinterized on a couple of years with no issues. Temps here usually include a half dozen or so days below zero with MOST of the time lows in the teens.

When using only the 12 volt system which is turned on and off manually, while towing we've towed in temps into the teens and still had no issues dumping tanks.

We use water bed heaters with Thermal weatherproof tape on the underside of the tanks. They never get too hot or won't burn the tank if empty. We merely just keep the tanks above freezing (if needed).