Preheat on a phaeton with a cummins engine

[Burly]

How long can you leave the pre heat on? I live in Canada and the temperature is set to dip to minus 25. I want to leave it on to keep the engine warm and assure starting on Christmas day for a departure south.

[Mekanic]

Do you mean the plug in 110V block heater?
If so you only need it on for about an hour to get the engine plenty warm for a easy start.
Years ago Ny tow truck was plugged in on a timer with a hour on,hour off,hour on,.... it started easy at any time. I was just saving money on the 600 watt usage.

[Tony Lee]

Rated for full time use so you can switch it on the day before if you want. That gives you a chance to make sure it is working.

[Poptop]

According to the owners manual for my Fleetwood w/Cat engine the colder it is outside the longer you should plug it in. At -25 degrees 6-8 hours would be plenty. The manual also says it doesn't hurt to leave it on all day/night. I'd plug it in the evening before you plan on leaving which is what I'm doing tonight for tomorrows departure.

[Burly]

Thanks everyone and have a safe trip.