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TKS not flowing but tank indicating fluid


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This weekend I gave the TKS system a try. Flipping to Anti-Ice it primed for a few minutes as expected then we could see fluid weeping from all the expected points. After about 15-20 minutes the system indicated it was priming again, fluid stopped flowing and we were basically done with that. However, the system still indicated that it has 1.0 Gal of fluid on the digital readout.

I'm not getting a high-pressure light.

I'm wondering if I'm out of fluid and it's just misreporting by a whole gallon? I do see a lot of fluctuations in the reported fluid level as the plane warms up on a trip (typically we "start" a trip with 0.7 Gal and end it with 1.2).

Theories appreciated.

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I would start by filling up the TKS tank and see how much it indicate . You can also use the windshield TKS pump to help in priming . It is unusual to end up with more at the end of a flight then at the beginning . 

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2 minutes ago, Alain B said:

I would start by filling up the TKS tank and see how much it indicate . You can also use the windshield TKS pump to help in priming . It is unusual to end up with more at the end of a flight then at the beginning . 

Yeah, topping it off is what I'm thinking. The magical accumulation of fluid on the gauge is what has me thinking it's unreliable.

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1 hour ago, djm181 said:

This weekend I gave the TKS system a try. Flipping to Anti-Ice it primed for a few minutes as expected then we could see fluid weeping from all the expected points. After about 15-20 minutes the system indicated it was priming again, fluid stopped flowing and we were basically done with that. However, the system still indicated that it has 1.0 Gal of fluid on the digital readout.

I'm not getting a high-pressure light.

I'm wondering if I'm out of fluid and it's just misreporting by a whole gallon? I do see a lot of fluctuations in the reported fluid level as the plane warms up on a trip (typically we "start" a trip with 0.7 Gal and end it with 1.2).

Theories appreciated.

Some tks thoughts...That's odd.... if not recently run it can take many many minutes to fully prime the system and see it running all the way outboard on the leading edges but you say you saw it. Also, start it in de ice to get a faster flow going and help prime system faster. The light on annunciator may be flickering and it will do so until fully primed and then go solid indicating normal flow. Lastly, the fluid flows best in cold temps so when warm out it will take longer. I have run that bird down to .5 or so gallons but no less... Maybe a little debris in tank or line? Maybe time for a new tks filter? Probably just some fluid and some time to get air out of lines and fully prime it. Should run it monthly going forward to avoid and issues. 

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4 minutes ago, djm181 said:

Yeah, topping it off is what I'm thinking. The magical accumulation of fluid on the gauge is what has me thinking it's unreliable.

I would be very nervous to fly in icing conditions without a perfectly operating TKS system and a tank full of fluid . 

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Thanks Zach - that's what I initially thought, but it was running properly for a while. We could see fluid weeping all along the wings and the light was solid on, but then fluid stopped flowing and the lights on the panel went back to the flickering-priming indication. I left it in this state for a good 15-20 minutes before giving up and saving the pump.

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19 minutes ago, Alain B said:

I would be very nervous to fly in icing conditions without a perfectly operating TKS system and a tank full of fluid . 

Agree but it is inadvertent not known ice on that bird so shouldn't be going out into known ice to start. However, it did get me out of very mild ice with no issues and allowed me to climb to Fl200 out of the weather. TKS systems must be run regularly regardless of known or inadvertent set up. I am guessing it is the fluid level or just some air in lines if wasn't run recently. 

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6 minutes ago, djm181 said:

Thanks Zach - that's what I initially thought, but it was running properly for a while. We could see fluid weeping all along the wings and the light was solid on, but then fluid stopped flowing and the lights on the panel went back to the flickering-priming indication. I left it in this state for a good 15-20 minutes before giving up and saving the pump.

Nice... I didn't fill it up full much due to the UL as I was always flying long distance with more than just me in there... try a top off/ adding some juice or try running on the higher flow rate for a bit to make sure lines are purged and panels are fully primed up nice. System is nice to have if you ever need it but it did work well for me on monthly runs.

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Just so everyone knows, we weren't flying in known ice, we were flying on a cold day, in a very thin layer through which we could see blue sky above and the ground below. It seemed like an ideal opportunity to try running the TKS in a low-risk environment with obvious outs. I'm pretty risk-averse when it comes to this sort of thing.

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If you run it in your hangar - do you see any fluid pooling anywhere under the plane - like either under the fill spot behind the wing (indicting a leak) or up at the prop (indicating at least it is flowing that far).

Last week I had a similar issue solved but I was getting a high pressure light so the fix was my filter was clogged.

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David, others have given good advice, so I'll just add quickly and summarize what you may or may not already know...

* Fill the tank and run it regularly to flush out old fluid keep the panels lubricated - every 30 days...more frequently in warm weather

* The indicator in the cockpit will always read fuller in-flight than on the ground, mainly because our aircraft sit 4.5 degrees nose-high.  So, the max you should be filling your tank on the ground is about 5.0 to 5.2 gallons.  In-flight, you will see this jump to about 6.0, so this may explain why you're seeing a lower amount on the ground before a flight and more at touchdown and taxi-in.  After touchdown, it does take several minutes for the level to return to what you are most-likely seeing at preflight/startup

* Not sure if you have a FiKi or Inadvertent installation, so if you have a windscreen pump, run that as well...on both pumps to verify their operation and adequate flow

Again, probably redundant info, but let us know how things are going after you go through some of this stuff.

Regards, Steve

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I think Steven nailed it.  I do see significant variations in my tank level indicator.  I always have a full tank in winter months and since it takes as much as fifteen minutes to prime the system, I can consume a gallon or two for priming alone when crossing the U.S.  The system is very accessible in my M20R as you simply pull the rear seats to see the tanks and pull the belly panel to access the pumps and tubing.  Typically pump systems don't like being run dry so I carry a five gallon jug of refill fluid for my cross country trips to reduce any inclination to be stingy with TKS Fluid as it's very economical when replenished from the fifty five gallon drum in my hanger.  

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I put in about half a gallon today then flipped on the master. Lo and behold the gauge reads 0.6 gal. Turning on the pump it starts priming. A couple of quick squirts from the windshield pumps and there is fluid coming out where it should be. A few minutes later I have fluid dripping from the leading edges. 

I guess the gauge just isn't reliable with an empty tank.

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  • 3 years later...
On 1/23/2017 at 7:55 AM, marooneypilot said:

This weekend I gave the TKS system a try. Flipping to Anti-Ice it primed for a few minutes as expected then we could see fluid weeping from all the expected points. After about 15-20 minutes the system indicated it was priming again, fluid stopped flowing and we were basically done with that. However, the system still indicated that it has 1.0 Gal of fluid on the digital readout.

I'm not getting a high-pressure light.

I'm wondering if I'm out of fluid and it's just misreporting by a whole gallon? I do see a lot of fluctuations in the reported fluid level as the plane warms up on a trip (typically we "start" a trip with 0.7 Gal and end it with 1.2).

Theories appreciated.

 

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I too have had issues with my indicator digital read showing correct gallons. Now when I first turn it on it reads correct gallons when full at about 6 gallons, but only for a second or two then it goes to zero or 0.1. Does anyone know the cause of this situation?

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The pressure sensor is in the tail, and it is very sensitive.  When the fluid is warm, a normally functioning system may not be able to make enough pressure to make the green light go steady. If you’re getting good flow from all the panels. And it’s hot outside, I wouldn’t sweat it.

-dan

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Lots of good advice here, allow me to summarize.

The pumps are not self priming, The windshield pumps are self priming and you should operate them to get your main pumps primed.

The windshield pump switch should be depressed no more than 5 second intervals. They build pressure then a solenoid releases that pressure. After 5 seconds, give it 5 then depress again.

Operate your system every 30 days. A good rule of thumb is if you have some data based avionics, run it when you change data bases. Operate all pumps including both windshield and main pumps

Keep your system filled. It keeps the seals in your tank and around the system supple and gives better head pressure to the pumps.

In warm weather it is not unusual to have continuous low pressure because of low fluid viscosity. As long as your panels weep good, you're good.

Change your filter at least every 24 months. It sounds weird but TKS fluid is like jet fuel in that it gets some sort of dusting  that clog the filter. Whatever it is, the filter bowl often looks like the filter bowl on a turbine when you pull it out. Maybe microbes? I don't know.

If you don't exercise your system regularly you will have to purge it, to get it back on line unless you want to spend lots of time and money sending dozens of gallons of fluid through the main pumps because once the panels loose their retained fluid, it is tough to get things going again. (ask me how I know)

 

 

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On 1/23/2017 at 9:55 AM, marooneypilot said:

This weekend I gave the TKS system a try. Flipping to Anti-Ice it primed for a few minutes as expected then we could see fluid weeping from all the expected points. After about 15-20 minutes the system indicated it was priming again, fluid stopped flowing and we were basically done with that. However, the system still indicated that it has 1.0 Gal of fluid on the digital readout.

I'm not getting a high-pressure light.

I'm wondering if I'm out of fluid and it's just misreporting by a whole gallon? I do see a lot of fluctuations in the reported fluid level as the plane warms up on a trip (typically we "start" a trip with 0.7 Gal and end it with 1.2).

Theories appreciated.

I had a condition like that which eventually I solved by running the system in the hangar and soon it was dripping from the back of the fuselage.  There was a leak in the primary pump and it was dripping out.  You need ground power to run it for twenty minutes in the hangar of course. ... or better outside the hangar as it makes a mess.

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