nfonville

Heater Operation

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Last week I flew from the DFW area to Denver Centennial.  The temperature at 8-10k was between -10 and -15C.  I pulled the heater on for a while and it worked fine blowing both hot air on the lower vent and defrost.  I'm kinda scared of heaters to due the age of my exhaust even though it's been maintained, inspected, etc.  So I turned it off.  Got into a slight rime icing. Climbed up 2K and icing quit.  Went to use the heater again and it did not blow hot air.  Did water/ice get somewhere it should not have been and something needs repairing? Have others seen this before? Thoughts?

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I think OP needs a CO meter to establish confidence in the heater and exhaust. I could see ice blocking the fresh air intake but have no experience there.

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While on the ground...

You get a lot of opportunity to see if the knob and cable are still attached to anything at the other end....

Mooneys have either slide gates or rotating rubber throttle valves to control hot air entering the cabin...

Check if those valves are operating still...

PP thoughts only, not a mechanic...

Best regards,

-a-

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34 minutes ago, larryb said:

I think OP needs a CO meter to establish confidence in the heater and exhaust. I could see ice blocking the fresh air intake but have no experience there.

I have the sentry ADSB device with CO meter. No evidence of a leak. Experienced a CO issue in a previous plane and extra just cautious.  The amount of air flow did not change just no warm air from the vents.  I'll be flying it Friday and test again.

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Two sources of air to the vents...

1) Cold air from outside... one gate/valve...

2) Really hot air from the heater muff... another / different gate/valve

 

Both airflows are driven by the plane moving through the air... no pumps or fans to fail...

3) So if you are getting cold air flowing in, and you closed that valve...   that valve probably needs some maintenance for the rubber seal.... a round rubber disc that is easy to source... it is leaking cold air in....

4) If you are not getting any hot air... sounds like a hose fell off the heater muff...

 

There is no way to turn off the heat... it is always being generated... just can’t get into the cabin unless you let it in...

if you try to let it in, but it doesn’t show up... it must be going somewhere else....

It is possible to have a third challenge... cold air isn’t getting to the heater muff, so there is no hot air to work with...

All the hoses are held in place with hose clamps... be ready to swap out some clamps and possibly update some hoses...

There are pics around here of the different types of gates and valves for the heat...

PP thoughts only, not a mechanic...

Best regards,

-anthony-

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Nf my Bravo has a difficult time providing heat when I reach a certain cold temp with no sun out like under the clouds.

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On 3/3/2019 at 9:00 AM, nfonville said:

Last week I flew from the DFW area to Denver Centennial.  The temperature at 8-10k was between -10 and -15C.  I pulled the heater on for a while and it worked fine blowing both hot air on the lower vent and defrost.  I'm kinda scared of heaters to due the age of my exhaust even though it's been maintained, inspected, etc.  So I turned it off.  Got into a slight rime icing. Climbed up 2K and icing quit.  Went to use the heater again and it did not blow hot air.  Did water/ice get somewhere it should not have been and something needs repairing? Have others seen this before? Thoughts?

I wonder if the cable that opens the flap for the hot air froze.

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Turbocharged Mooney heating systems don’t provide a lot of heat.  The heat exchanger in the Bravo is on the forward cross over pipe and takes air in between the 2 alternators.  It’s unlikely that it iced over.

To improve heater performance check to see if the butterfly door in the cold air inlet from the Naca duct on the right side of the fuselage has 4 -1/2” holes in it, many do.  Sealing these holes will help.

Clarence

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When I flew last friday, the heat was good and strong.  Opened and closed valve multiple times and no issue.  The temperature was +5 C.  I'm thinking something froze up when I hit the light rim ice.  Flying tomorrow at a higher altitude and it will be colder so I'll test some more.

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