frozen water lines

One space heater won't make much difference, the cold ground will soak up the heat.

Find whichever pipes are frozen and wrap with heat trace, or park a 40 watt incandescent in the general area.

Get some heat tape and wrap the pipes with it. That concentrates the heat where you need it.

Amazon


You want it with a thermostat so it will turn itself on and off.

If you can block the rapid escape of air from under your trailer then placing a space heater (maybe even two) would be a great way to thaw things out under there. Remember hot air rises so it will heat the best at the underside of your trailer. If it is real drafty under there then this would not work very well.

Water flows using pump but doesn't using city water connection.....city water inlet check valve assembly frozen or jammed

Continue using fresh water tank/pump and refill as necessary

Just use hose to top off and then drain put away until needed again.

Open the interior cabinet to access the inlet. Leave it open to get the interior heat to reach that inlet pipe.

My 5th wheel is completely sealed underneath so I can't get to the lines. How about one of those tank heater type blankets to put on the undercarriage?

By the way, many thanks for all the suggestions. Maybe next year I'll be in Arizona for the winter. Just though I'd give this a try since it is incredibly beautiful here near Bryce Canyon.

DeMcCrae wrote:
My 5th wheel is completely sealed underneath so I can't get to the lines. How about one of those tank heater type blankets to put on the undercarriage?

Everyone's fiver has a sealed underbelly. When you need to work under there you have to 'drop the belly'. A tasked dreaded by all. There should be many screws along the edge of the plastic, that's Coroplast by the way. You remove enough screws to pull down the coroplast in the area you need to work on. You will want a cordless screwdriver or a cordless drill to do this.

There will probably be a layer of fiberglass insulation being held up by the belly. Hopefully it will be -dry- fiberglass. If that is missing then you have an explanation why the pipes froze.

That's why I doubt a heater of any sort will work under the fiver since there is a layer of coroplast and fiberglass insulation in between the heater and the piping.

I guess your furnace isn't heating the areas where the pipes are?

I don't think the inlet pipe will be accessed through the underbelly.
There should be access from an interior panel. Or I could be wrong.