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mikey70

No Cabin Heat-SOLVED!

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The problem of no cabin heat has been well documented here and as suggested, I covered the cabin openings with foam blocks which did indeed reduce the air infiltration, however I still wasn't getting any heat. I checked the butterfly valve on the firewall and it was working correctly. When I inspected the air plenum that feeds the heat shroud I noticed that the rubber gasket on the front is made up of individual pieces of rubber and not the one piece that is shown in the parts manual. When installing the bottom cowling, the bottom piece of rubber will more than likely position itself so as to block the airflow into the heat shroud. No air flow = no heat. Its easy enough to tuck this rubber piece under the cowl opening after the cowl is fastened and that fixed the problem of no heat. The guy I bought the airplane from did not know about it either. He said the heater did not work. I believe this could also lead to a lack of carburetor heat as well so its more than just creature comfort. 

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Have you tested it since the repair? I have 4 CTLS's and the problem is the same in all of them. I have blocked all of the places where air can come in an that did stop the breezes but still not heat. I have changed the rubber piece and made sure they are in place. Still no heat. The latest thing I did was buy a small smoke machine and blew smoke into the intake. I found a massive amount of leaks around the heat shield that goes around the muffler. I sealed that with RTV and still the heat is not acceptable. Even when using the smoke I can't get the smoke to come through the heat diffusers in any great amount. The valve is working properly. The heating system just does not work. I have seen where others have said they can fly in a tshirt but I think they have CTSW's. 

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For the CTSW the rubber flap being out of place will not effect the carb heat.

Al, my experience was that the heat worked OK, but I am further South, and likely not trying to fly in as cold weather as you. The other thing is the valve doesn't need to be just working. it needs to be working perfectly. It has to go to the extremes of full open and closed. You might also try removing the diffusers. With them installed there may be to much restriction to the airflow, causing more of the heat to be pushed up to the cold windshield where it cools to quickly to do any good. 

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I have flown since I put the flap back in place and it is much better. With OAT at 40 F I had the heat valve about 1/3 open and was comfortable in a light jacket. In my case the plumbing was all ok, I just wasn't getting any airflow INTO the heat shroud. In my case, I was not feeling any air coming in to the floor vents or windshield. Perhaps you have already tried this, but you might be able to pinpoint where the restriction is by disconnecting the duct hose at the firewall heat valve and push the smoke through just the heat shroud. If that works ok then inject the smoke right at the heat valve and  see how that works. 

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I flew to Denver a couple weeks ago with my wife and nearly froze some of her parts off. The outside air temp over Wolf Creek Pass was in the teens. the cockpit temperature couldn't have been much warmer as, all of the sudden, the heater was not providing its usual warming for the sides of our ankles closest to the pedestal.

Incidents like this make it ever harder to get my wife to go with me.

So when we I got home, I took a close look at it. The diverter plate in the heater valve box (officially called the "cabin heater choke") was only swinging forward a tiny bit from the closed position. Long story short; one of the fasteners that hold the box in place had loosened enough that the head was standing proud from the bottom of the box. The edge of the diverter plate was catching on it. I could have saved a lot of work by just sticking a small Allen wrench down into the box and tightening it, instead of taking the whole thing apart.

Keep this in mind if you suspect you may have the same problem.

Mike Koerner

 

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How to fly in short sleeves when it's single digits outside. Finding and fixing heat issues and making the cabin cold air free.

Start at the front. The lower air duct opening for the heated air should align with the opening. If it doesn't loosen the two clamps on the muffler and move the duct to a more aligned position. This is usually up more. Make sure when the cowl is on that the rubber baffling around the duct is not in the way of the opening. When you did a hose change the 1 3/4" heater hose should have been replaced because these can get vibration holes and split. Next make sure when you pull the cabin heat knob the trap door in the engine compartment in the air diverter opens and closes fully. If not just adjust the cable. Next remove the center instrument panel and make sure the hose inside for the heat ducting is connected and that the heated air duct that comes out the side of the lower panel by your feet is properly lined up with the opening. I see many halfway blocked due to poor alignment. Next use some clear 3" tape and place this over the openings up by your head on each side of the fuselage. and this includes the fuel sight tube opening. If you block up only one or two air just gets forced out the other. Then take some soft foam and cut it into a "C" or an "O" and put it around the metal spar pins up in the spar box. Plug the front and back of the pin opening. Next go to Home Depot or Ace Aviation and gets some 3/8" soft foam with a sticky tape back. This will go around the door edges. It goes all the way around the out side of the door seal on each door. make sure your doors do not have a big air gap up at the front edge. You can either add a little extra foam or just remove the door and relocate the hinges about 1/8" - 3/16" forward and the door will never leak again.

Now your air flow is correct and aligned and the cabin sealed from cold air intrusion and it wall be nice a warm. I can fly easily in the single digits with nothing more than a tee-shirt with good cabin heat. Most of the time it's only open half way. 

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I have been flying the Sierra in winter in Tshirts since my Rotax 503 powered Ultra Light like design in the 1990s.  It works well if you have the plumbing hooked up right and enough air leaks plugged.

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Roger, I have tried to align the intake on the shroud a number of times, but the exit at the aft of the shroud keeps it from aligning. Any hints?

 I am pondering widening the flexible “seal” around the outside of the intake.

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Hi Doug,

I haven't had one I couldn't slide up as far as the radiator which should be plenty far. Try and adjust or flatten the hose on top of the muffler.

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On 1/8/2019 at 8:54 AM, Roger Lee said:

How to fly in short sleeves when it's single digits outside. Finding and fixing heat issues and making the cabin cold air free.

Start at the front. The lower air duct opening for the heated air should align with the opening. If it doesn't loosen the two clamps on the muffler and move the duct to a more aligned position. This is usually up more. Make sure when the cowl is on that the rubber baffling around the duct is not in the way of the opening. When you did a hose change the 1 3/4" heater hose should have been replaced because these can get vibration holes and split. Next make sure when you pull the cabin heat knob the trap door in the engine compartment in the air diverter opens and closes fully. If not just adjust the cable. Next remove the center instrument panel and make sure the hose inside for the heat ducting is connected and that the heated air duct that comes out the side of the lower panel by your feet is properly lined up with the opening. I see many halfway blocked due to poor alignment. Next use some clear 3" tape and place this over the openings up by your head on each side of the fuselage. and this includes the fuel sight tube opening. If you block up only one or two air just gets forced out the other. Then take some soft foam and cut it into a "C" or an "O" and put it around the metal spar pins up in the spar box. Plug the front and back of the pin opening. Next go to Home Depot or Ace Aviation and gets some 3/8" soft foam with a sticky tape back. This will go around the door edges. It goes all the way around the out side of the door seal on each door. make sure your doors do not have a big air gap up at the front edge. You can either add a little extra foam or just remove the door and relocate the hinges about 1/8" - 3/16" forward and the door will never leak again.

Now your air flow is correct and aligned and the cabin sealed from cold air intrusion and it wall be nice a warm. I can fly easily in the single digits with nothing more than a tee-shirt with good cabin heat. Most of the time it's only open half way. 

I’ve got a 2005  ctsw that I just picked up and my door definitely needs moved forward about an 1/8 inch. There is an air gap at the front and looking at the door gaps with the door closed the rear is almost touching. 

I was wondering how you relocated them forward? My hinges aren’t slotted. It looks like the are just screwed in. 

Was hoping for some insight before I just started taking things apart! 

Thanks!!

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You have two choices.

If the gap at front is small then just applying some soft foam door seal all the way around the outside edge of the existing rubber door seal will take care of it. I would do this anyway if I was sealing the cabin from cold air. 

Mine on my 2006 SW was too wide at the front (you could see daylight through the gap) and the door did rub at the back edge. The hinge plate on top of the door that the screws for the hinge screw into has a metal plate inside. I just removed my hinges from the top plate. Filled the old holes with JB Weld and drilled new holes about 1/8" forward, tapped the screw holes and remounted my doors. They were a perfect fit then and the smoothest doors on a CT I have ever used with the latching mechanism. 

 

My opinion on the door gaps is this;

They don't leave the factory this way. After a long time out in the field and with the weight bearing down the fuselage it settles just slightly and the door opening elongates just a tad allowing for that gap. Just my thought.

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Thanks for the info. I was wondering about the plate inside. I just didn’t know what there was inside of there structurally to attach too other than just having screws held in by JB weld. I’m glad there is a metal plate. That makes me feel better about repositioning the door. 

Mine is just like yours was. If it’s bright outside I can see a small bit of daylight at the front of the door shining through. When I was out of town I left it sitting on the ramp overnight and went back the next day to find the footwell full of water!!

I’ll have to give that a looking into. That sounds like it could be the best option

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2 hours ago, IndianaCTSW said:

 

Mine is just like yours was. If it’s bright outside I can see a small bit of daylight at the front of the door shining through. When I was out of town I left it sitting on the ramp overnight and went back the next day to find the footwell full of water!!

 

There should be a drain hole in the footwell. You need to make sure it is not plugged up.

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Have you tested it since the repair? I have 4 CTLS's and the problem is the same in all of them. I have blocked all of the places where air can come in an that did stop the breezes but still not heat. I have changed the rubber piece and made sure they are in place. Still no heat. The latest thing I did was buy a small smoke machine and blew smoke into the intake. I found a massive amount of leaks around the heat shield that goes around the muffler. I sealed that with RTV and still the heat is not acceptable. Even when using the smoke I can't get the smoke to come through the heat diffusers in any great amount. The valve is working properly. The heating system just does not work. I have seen where others have said they can fly in a t shirt but I think they have CTSW's. 

Does anyone have a warm CTLS?

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4 hours ago, Tom Baker said:

There should be a drain hole in the footwell. You need to make sure it is not plugged up.

I will definitely be checking that out. Thank you!! 

 

Also so as far as flying in a T shirt I will have to do some work on that too. I had multiple layers including a winter jacket in single digits and I was freezing!! Hopefully I can get that lined out. Thanks for the help!

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I have been asking about this for quite some time. It seems the only answers I get are from CTSW owners. I think their system must be different in some way because they claim it is warm.

I have 4 CTLS and  they are all the same. COLD

Well we are in the process of replacing an engine (3300 hours) in one and I used a smoke machine to find the leaks. My heat shroud now looks line a giant piece of red RTV. It had all kinds of leaks. They are now sealed. Even then very little heat went into the cabin. I have checked it all. The valve for heat is working perfect, opening and closing as it should. I have all the draft holes in the cabin sealed and replaced and check all the door seals. With everything now sealed and using the smoke machine I found out the the valve in the Carb heat is not closing 100%. 

I don't know what the part is called. Couldn't find it any of the manuals. It is the cylindrical thing on top and behind the engine. When you pull the carb heat cable it is supposed to open and close the carb heat. My thinking is that the air flow will take the path of least resistance and therefore not much coming into the cabin. When making sure the carb heat is 100% off, U get tons of smoke into the cabin. Hopefully this is the fix. 

Engine should be done tomorrow and it we have clear skies I can test it. Single digit temps so it will be a good test.

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On ‎1‎/‎5‎/‎2019 at 7:41 AM, mikey70 said:

The problem of no cabin heat has been well documented here and as suggested, I covered the cabin openings with foam blocks which did indeed reduce the air infiltration, however I still wasn't getting any heat. I checked the butterfly valve on the firewall and it was working correctly. When I inspected the air plenum that feeds the heat shroud I noticed that the rubber gasket on the front is made up of individual pieces of rubber and not the one piece that is shown in the parts manual. When installing the bottom cowling, the bottom piece of rubber will more than likely position itself so as to block the airflow into the heat shroud. No air flow = no heat. Its easy enough to tuck this rubber piece under the cowl opening after the cowl is fastened and that fixed the problem of no heat. The guy I bought the airplane from did not know about it either. He said the heater did not work. I believe this could also lead to a lack of carburetor heat as well so its more than just creature comfort. 

image.png.a22f15aff5936d90368df46bfe3c72fc.png

As far as covering up the openings between the back of the seats (CTLS) and the baggage areas, any ideas what to use?  I'm a little skittish using foam board, as I wonder whether it's a hazard in the event of a fire.  Light metal could have its own issues.

Appreciate any advice.

Andy

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If you seal the cabin holes up on top around your head and the spar pin holes and seal the cabin doors I never had a need to seal up behind the seat. I have though seen a few use 2" foam cut to fit in that opening.

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I have been working on mine today and haven’t got to a point to try it. I did find that  the flap that is controlled by the heater cord was not opening all the way. 

The other thing I did was went and got one of those window kits for a home that uses double sided tape and shrink wrap plastic and I covered the holes up with that. It looked a lot better than the packaging tape I put on there the first time. Lol 

I would think you could also use that for the openings behind the seat if you didn’t have anything in the baggage area that could put a hole in it. 

 

I also used used some foam window seal from Home Depot to help seal up where my door did not seal at the front of the door. 

6D444FC2-CA88-4FC7-9189-64A271F837C5.jpeg

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On ‎1‎/‎26‎/‎2019 at 7:35 PM, Al Downs said:

I have been asking about this for quite some time. It seems the only answers I get are from CTSW owners. I think their system must be different in some way because they claim it is warm.

I have 4 CTLS and  they are all the same. COLD

Well we are in the process of replacing an engine (3300 hours) in one and I used a smoke machine to find the leaks. My heat shroud now looks line a giant piece of red RTV. It had all kinds of leaks. They are now sealed. Even then very little heat went into the cabin. I have checked it all. The valve for heat is working perfect, opening and closing as it should. I have all the draft holes in the cabin sealed and replaced and check all the door seals. With everything now sealed and using the smoke machine I found out the the valve in the Carb heat is not closing 100%. 

I don't know what the part is called. Couldn't find it any of the manuals. It is the cylindrical thing on top and behind the engine. When you pull the carb heat cable it is supposed to open and close the carb heat. My thinking is that the air flow will take the path of least resistance and therefore not much coming into the cabin. When making sure the carb heat is 100% off, U get tons of smoke into the cabin. Hopefully this is the fix. 

Engine should be done tomorrow and it we have clear skies I can test it. Single digit temps so it will be a good test.

Al,

The whole shroud is dedicated for cabin heat on the CTSW. For the CTLS it is shared with carb heat. I suspect your notion is correct that you are losing hot air to the carb heat. You need to make that valve shut as tightly as possible, or the vacuum  in the airbox is going to suck up all the heat.

Another thought is the tighter you seal the cabin the harder it is to push air inside. In other words the flow from the heat pressures up the cabin stopping the flow. If you can figure a way to create a little vacuum in the cabin it will pull more heat inside. It has been my experience that if you slide one of the sliding windows slightly aft that the low pressure around the fuselage will move air out of the cabin. It might be worth a try.

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On 1/26/2019 at 2:16 PM, Tom Baker said:

There should be a drain hole in the footwell. You need to make sure it is not plugged up.

I just looked and the only drain hole I can find is on the side of the footwell about 2 inches up and 2 inches back. Should there be another one?

having just that hole still let’s a pretty big puddle gather. Lol

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45 minutes ago, IndianaCTSW said:

I just looked and the only drain hole I can find is on the side of the footwell about 2 inches up and 2 inches back. Should there be another one?

having just that hole still let’s a pretty big puddle gather. Lol

I have a CTSW in the shop, and it has one in the very rear inboard corner. This would be the lowest point of the compartment.

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Sorry to beat a dead horse... I flew twice now in cold weather (below freezing).

First time out, 16 degrees, Sunny, early AM... heat on... I was hot wearing a jacket, took the jacket off and flew in a sweater and was fine.

Second time out... today, early AM... I was "chilly" but comfortable with only a sweater on.  Conditions were different.  20 degrees, but no sun... cloudy.  

The site holes are covered with clear tape (see red arrow) which keeps the draft out.  The plane is an "i", so no carb heat to scab the heated air. 

I hope this helps.

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