JBlueSkys Posted November 27 Report Posted November 27 Hello Fellow Mooney Aviators! We have a Mooney M20F with the Reiff Turbo XP hot band and oil sump heater with thermostat. This is our first winter to use the airplane and I was wondering if someone has some feedback on how to properly heat the engine and how long to keep it plugged in before use? It has a thermostat so I’m assuming it cuts off at a preset temperature? Sent from my iPhone using Tapatalk 1
NickM20F Posted November 27 Report Posted November 27 Do you know how many hours the install took on the reiff? I’m thinking about getting one installed on my M20F as well
JBlueSkys Posted November 27 Author Report Posted November 27 Unfortunately I don’t know. It had it already installed when we purchased it. Sent from my iPhone using Tapatalk
Andy95W Posted November 27 Report Posted November 27 I have the same system. I preheat if it’s less than about 35°. I do one hour if it’s about 32-35, two hours if it’s 20, 3 hours if it’s 10. Reiff says 3-5 hours, or 10-12 hours for “maximum heating”. I based my times from their chart:
JBlueSkys Posted November 27 Author Report Posted November 27 Thank you! That helps me out a lot! Happy Thanksgiving!Sent from my iPhone using Tapatalk 1
Andy95W Posted November 27 Report Posted November 27 @JBlueSkys- Happy Thanksgiving to you! I forgot to mention, that’s with a blanket on the nose and foam in the cowling inlets. Enjoy, good luck!
exM20K Posted November 27 Report Posted November 27 The chart is about what I see in a lightly heated (50*) hangar with cowl plugs installed. I’ll typically plug in after dinner before the next morning’s flight. This is among the many joys of living at an airpark. -dan
Fritz1 Posted November 27 Report Posted November 27 The turbo XP is about as powerful as they come, even when it is lousy cold let's say below 0 dF plugging it in for two hours allows you to start the engine without causing any damage, I live 10 min from the airport, drive over in the evening before a morning takeoff, typically plug the heater in below 60F, will make an effort to get the preheat going below 40 dF, heater is paid for, power is paid by the airport, plugging it in can't hurt.
hypertech Posted November 28 Report Posted November 28 I plug it in the night before I plan to fly. Something on the cowl - even just a moving blanket - makes a huge difference.
Hank Posted November 28 Report Posted November 28 When I lived in WV, I bought a cell switch, and would plug the Reiff into it after every winter flight. Depending on the severity of the cold, I would either call it the night before or when I woke up the morning of a flight. Now in Sweet Home, I do not find this necessary, but will sometimes plug in the heater as soon as I get to the airport, and allow it to heat for an hour or so. This lets me preflight, load baggage and check weather, enjoy my coffee and make a pitstop before unplugging and pulling the plane out of the hangar.
dkkim73 Posted November 28 Report Posted November 28 Reiff XP here as well. Great system. I find it works really well the night before. No guessing, and the excess heat does no harm. It's been great on those *really* cold Northern days.
exM20K Posted November 29 Report Posted November 29 33 minutes ago, dkkim73 said: Reiff XP here as well. Great system. I find it works really well the night before. No guessing, and the excess heat does no harm. It's been great on those *really* cold Northern days. I think I pay around $0.19 per KWH, so a 12 hour preheat costs about $2, or, in context, 0.02 AMU. -dan
mhrivnak Posted November 29 Report Posted November 29 I have the Reiff Turbo XP also, and it is very effective. The chart above looks about right from my experience in relatively mild winters. I bought a used comforter at a thrift store for about $3 and put that over the cowling. I use a spring clamp to clip the two sides together just under the spinner, which covers the cowling inlets and keeps the blanket tight around the front. If you have an engine monitor (and hopefully you do!), keep an eye on the CHTs there for an idea of how the heater is doing.
DXB Posted November 29 Report Posted November 29 On 11/27/2025 at 7:34 PM, JBlueSkys said: Hello Fellow Mooney Aviators! We have a Mooney M20F with the Reiff Turbo XP hot band and oil sump heater with thermostat. This is our first winter to use the airplane and I was wondering if someone has some feedback on how to properly heat the engine and how long to keep it plugged in before use? It has a thermostat so I’m assuming it cuts off at a preset temperature? Sent from my iPhone using Tapatalk Unscrew the dipstick and leave it plugged in all the time with the in the winter, when most folks fly less. It will keep the inside of the engine bone dry and invulnerable to corrosion.
skykrawler Posted November 29 Report Posted November 29 3 hours ago, DXB said: Unscrew the dipstick and leave it plugged in all the time with the in the winter, when most folks fly less. It will keep the inside of the engine bone dry and invulnerable to corrosion. Warm air holds more moisture than cold air. Cell service operated switches are great. An alternative for a night before effort is a inexpensive 24 hour timer like for Christmas lights set for a couple of hours before engine start time. 1
GeeBee Posted November 29 Report Posted November 29 If that were all true, all guns in a gun vault would rust away from the use of heating elements, but they don't. Aviation Consumer discovered this, so did American Bonanza Society. I keep my engine continuously heated with an AeroTherm Deuce to 70 degrees with no problems https://www.reiffpreheat.com/Article-Fiorentini-ContinuousPreheating.pdf 1
exM20K Posted November 29 Report Posted November 29 I believe the corrosion concerns came from the sump-only heating systems, and they are valid. The mechanism was: sump heat warms oil and evaporates moisture into the warmed air. warm, more humid air moves through the engine. the un-heated cylinders and other thermal masses, if below the dew point of the heated sump air, will condense out the moisture. However, if everything is warmed up to 140, there is no mechanism for condensation. -dan
DXB Posted November 29 Report Posted November 29 9 hours ago, skykrawler said: Warm air holds more moisture than cold air. Cell service operated switches are great. An alternative for a night before effort is a inexpensive 24 hour timer like for Christmas lights set for a couple of hours before engine start time. There is no need for a cell switch. RELATIVE humidity is what determines moisture exposure of a surface and resulting corrosion rate, NOT absolute moisture content. The dryness you experience in your heated house in the winter without a humidifier is experiential evidence. The higher temp of the heater would markedly accelerate corrosion at high relative humidity, but in the very low relative humidity in your engine with the heater, there is negligible effect. As long as you have a engine heater that warms all components well above the dew point, continuously leaving the heater on in winter is an ideal solution.
Pinecone Posted 5 hours ago Report Posted 5 hours ago On 11/29/2025 at 7:21 AM, skykrawler said: Warm air holds more moisture than cold air. Which means the same moisture content will be lower relative humidity. Two drivers of corrosion. Liquid water (condensation) and high RH. Heater addresses both issues.
Pinecone Posted 5 hours ago Report Posted 5 hours ago On 11/29/2025 at 12:30 PM, exM20K said: I believe the corrosion concerns came from the sump-only heating systems, and they are valid. The mechanism was: sump heat warms oil and evaporates moisture into the warmed air. warm, more humid air moves through the engine. the un-heated cylinders and other thermal masses, if below the dew point of the heated sump air, will condense out the moisture. However, if everything is warmed up to 140, there is no mechanism for condensation. -dan Except I have a sump only heater. I also toss a remote thermometer under the cowl. After overnight (in a hangar so no wing) the under cowl temp is typically in the 70s. So everything is nice and warm.
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