-52 and almost new Rinnai direct vent furnace

After 18 yrs of wood heat only we got a back up (chuckle ) propane heater .It would not work at -30 .Thank you Lord that we do not have to depend on it ! It was down to -52 on Saturday morning that felt good compared Friday when it was -35 and a 25 MPH wind . Propane supposedly is no good at -40 due to not turning into gas .Do some batches of propane have impurities and moisture ? This brand of furnace is very good according to most folks here that have them and is only 2 yrs old.

Depends on how low the fuel is in the tank and also .... .believe it or not......the wind can have an impact on the temperature in the tank even though it has no sense of feeling.

It could be a froze up regulator. Mine has been working at 30 below to 33 below. 24 below this morning with a 25-35 mph wind with gusts over 50. It is about a full time job keeping this old farm house warm in this wind. It show wind all night and all tomorrow.

My boiler it going good I’m glad I rebuilt it when I did now it runs like clockwork. I need a delay thermostat for it I’ve been running both the LP furnace and the boiler together. The boiler heats the house for long periods of time then the LP furnace kicks in with the delay thermostat to bring it back up. In mild weather the LP never runs the element heats the house no fan needed.

It must be working the LP truck showed up a few days ago the tank only took 75 gallons since the last fill that was surprising it’s been mild but cold at night I expected twice that amount.

Put heat tape on the propane tank and it will go a lot colder.

I have had to make a bucket with hole to stop the wind on two on the exhaust pipe

MJM nailed it .Well folks .Problem solved ,neighbor has one like mine and he said the same as Mark ,hot water on regulator .Finding out now that it has been common last few days .and this weather is fairly common here and the problem just shows up now .Probably some issue with the quality of the propane with moisture .We had this furnace and tank put in June 2022 and barely ever used it as we have lots of wood so had it put in so we could torment my sister in Texas for a few weeks .So now we are a bit smarter than before ! Thanks to all for your suggestions .