Yere, it's been cold here in Cranbrook, BC
It's February 10th today and we have spent the last two days without any water to the kitchen. Water to the bathroom has been unaffected thankfully as it's right above the service area where the furnace etc. are located. which is always warm.
The hot and cold water lines run from the service area down under the floor then back about 5 feet then come up through the floor and into the cupboard under the sink. No mystery there but as it turns out there are some low-point drains that poke through the skin that covers the all of the underneath of the RV. We originally thought that as the tanks are heated so should be the path that the water lines follow. I mean that they are close to the ducted heating. The tanks are infact heated as they are close to the furnace ducting.
A heater pointed at the low-point drain fixed the problem within 30 minutes and we were surprised at how easy the fix was. At this point we have three electric heaters in the RV two that basically have been running for about 2 months non-stop and now a third that lives under the RV. This one can be turned on when required to de-ice water lines.
We should be good for about minus 20 degC we hope and besides, it's all a leaning process. I guess in a way we are still getting setup as full-timers and learning how to cope in certain situations but Canadian winters are a challenge.
EDIT: Feb 12, 2021
Last night our furnace stopped working the temperature inside the RV dropped to 15 degC while it was a chilly -26 degC I noticed it was cooler than it should be in the RV as Raewyn and I were being smothered by Lilly and Tux as their fuzzy, furry coats weren't providing sufficient warmth. I reset the furnace (shut it down then restarted it) and found that it would run for about 20 seconds then shut down. While I come from a technical background I am not familiar with furnaces. A quick trip around YouTube and I came across this little video that addresses the problem.
The issue was that the sail switch get's coated in dust particles, fluff of fur from pets and prevents the sail switch (a little micro switch with a large fin on it) from closing and allowing propane to flow. It's a safety device that checks that the fan is running before the burners are lit. It's an easy fix which is nice as working in -26 is not fun.
A Dometic furnace with the cover and exhaust ports removed. Circled in red is the location of the sail switch just below is a reset button. Removal is dead easy it's just two screws just be careful removing the switch.

Switch removed fluff etc. will build up at the base of the long silver switch lever carefully clean of lint and remount in to fan housing and replace the furnace cover and test.
Note: The linked YouTube video is not my property but belongs to this guy Our Road To Camelot It was the first video that was returned when googling "RV furnace runs then shuts down".
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