TKS High Pressure Light

[AZOutlaw]

I have a continuous High Pressure light on the TKS panel.  CAV Ice's recommendation is to change the filter, which we did, with the same result.  I have tried the reset button and it does shut the light off occasionally, but not always.  If it does go off, it comes back on soon.  I've run a couple of gallons of fluid through the system recently as well.  Any thoughts on what to check next?  I'm guessing it's a bad pressure switch, but while I do have wiring diagrams for what seems to be all Ovations, I can't find anything that has the TKS wiring included.

[Andy95W]

How old is your fluid?  A friend had a TKS Ovation that had similar symptoms. He bought TKS fluid by 55 gallon drums.  He learned that as time went by, the fluid gained viscosity.  Not noticeable except that it would turn on the high pressure light.

Went he started buying the fluid by 1-gallon jug, the problem went away (for the most part.). It’s probably not the only cause, but definitely one of them.

[Bolter]

18 minutes ago, Andy95W said:

How old is your fluid?  A friend had a TKS Ovation that had similar symptoms. He bought TKS fluid by 55 gallon drums.  He learned that as time went by, the fluid gained viscosity.  Not noticeable except that it would turn on the high pressure light.

Went he started buying the fluid by 1-gallon jug, the problem went away (for the most part.). It’s probably not the only cause, but definitely one of them.

Worth noting that the Davies TKS is sold in 1 gallon bottles on Amazon for a fair price.  Because of the ageing issue and the convenience of handling smaller bottles, I just use 1 gallon bottles.  The small increase in cost per gallon is acceptable for my usage level.  

[dkkim73]

Does anyone know why the fluid becomes more viscous? Is it a chemical reaction, or offgassing of volatile components? Or something else? Just curious how to mitigate this if at all (storage temp, UV etc). Good tip on the small bottles. It's going to be that season again soon...

@AZOutlaw they have ways of checking out the system by fitting pressure gauges to various points. Had to do that with mine at the initial annual at Mooney. I had some problems that are fuzzy at the moment, and a bad proportioning unit in the tail among other things. But it sounds like making sure the fluid is good would be a less expensive first step since you've already addressed the filter. Good luck! 

There is a person from CAV systems on the board, as well. @CAV Ice

[GeeBee]

1 hour ago, dkkim73 said:

Does anyone know why the fluid becomes more viscous? Is it a chemical reaction, or offgassing of volatile components? Or something else? Just curious how to mitigate this if at all (storage temp, UV etc). Good tip on the small bottles. It's going to be that season again soon...

@AZOutlaw they have ways of checking out the system by fitting pressure gauges to various points. Had to do that with mine at the initial annual at Mooney. I had some problems that are fuzzy at the moment, and a bad proportioning unit in the tail among other things. But it sounds like making sure the fluid is good would be a less expensive first step since you've already addressed the filter. Good luck! 

There is a person from CAV systems on the board, as well. @CAV Ice

Because the alcohol evaporates. In the scotch whiskey business it is called “the angels share”.

[dkkim73]

If they see me pouring Popov into my TKS tank they will be only moderately surprised. 

ETA: I do not begrudge my guardian angels their share. BTW Anyone know who is the patron saint of in-flight icing? 

[AZOutlaw]

11 hours ago, Andy95W said:

How old is your fluid?  A friend had a TKS Ovation that had similar symptoms. He bought TKS fluid by 55 gallon drums.  He learned that as time went by, the fluid gained viscosity.  Not noticeable except that it would turn on the high pressure light.

Went he started buying the fluid by 1-gallon jug, the problem went away (for the most part.). It’s probably not the only cause, but definitely one of them.

It's been around awhile but I only buy the 2.5 Gal bottles so I don't have a big drum of it.  I live in AZ and we rarely see ice!! I dumped in a new bottle the other day and ran a good portion of that out on the ground thinking that might be the case.  The stuff in the tank has been in there a couple of years but it was down to about 3 gallons.  I'll admit, I don't run it monthly as CAV suggests as I hate the clean up and the dripping in the hangar for the next 2 weeks. 

Anyone know what "Minimum Dispatch" refers to?

[Scottknoll]

Just bought the 2.5 gallon bottles from Boeing. Less than $18/gallon, but you have to get an account with them and had to pick it up at the local warehouse. The shipping can be expensive.

[Will.iam]

1 hour ago, AZOutlaw said:

It's been around awhile but I only buy the 2.5 Gal bottles so I don't have a big drum of it.  I live in AZ and we rarely see ice!! I dumped in a new bottle the other day and ran a good portion of that out on the ground thinking that might be the case.  The stuff in the tank has been in there a couple of years but it was down to about 3 gallons.  I'll admit, I don't run it monthly as CAV suggests as I hate the clean up and the dripping in the hangar for the next 2 weeks. 

Anyone know what "Minimum Dispatch" refers to?

Minimum dispatch is for planning operations the minimum you can have and T/O if you are flying part 135 or 121 ops. As a part 91 operator maybe it’s advisory?  

[Fritz1]

Most likely old fluid, run an entire tank on the ground and it will most likely go away, then run about 5 min on each pump every month, once it stops dripping in the hangar it is time to re-prime, i typically use 7.5 to 10 gal per year, 2.5 gal jugs, the system is reliable and powerful, pumps need exercising, membranes need to be kept wet so system flows on all surfaces within 3 min

[Will.iam]

1 hour ago, Fritz1 said:

Most likely old fluid, run an entire tank on the ground and it will most likely go away, then run about 5 min on each pump every month, once it stops dripping in the hangar it is time to re-prime, i typically use 7.5 to 10 gal per year, 2.5 gal jugs, the system is reliable and powerful, pumps need exercising, membranes need to be kept wet so system flows on all surfaces within 3 min

So if the system needs to be ran at least once per month and i assume you are flying at least once per month as well why not run it for 5 mins in the air instead of in the hanger and having it make a mess on the hanger floor? Just curious to the logic. 

[dkkim73]

11 minutes ago, Will.iam said:

So if the system needs to be ran at least once per month and i assume you are flying at least once per month as well why not run it for 5 mins in the air instead of in the hanger and having it make a mess on the hanger floor? Just curious to the logic. 

Once you get back to the hangar it just randomly exudes fluid. Temperature change... fluid puddle. Move the plane.. fluid puddle. You get the idea. Like having a coworker with a head cold. 

[Fritz1]

I rather run the system on the ground and watch wetting and drip pattern, royal mess but beats having none or boots, would like bleed air though

[CAV Ice]

@AZOutlaw I sent you a PM.

[wombat]

I fly over the Cascades a lot.   I have a 30 gallon barrel that I expect I'll get through most of this winter.

[AZOutlaw]

Problem solved.  I was trading emails with Jason at CAV ice and after disconnecting the TKS lines to the switch, we still had a high pressure light.  Jason said we could send it in for a rebuild so we went to figure out where to cut or disconnect the wiring.  I was a little confusing as the wire diagram shows 2 wires, the switch has three.  I'm going to assume the NO wire just dead ends in there somewhere.  Long story but we pulled on one of the wires and it came right out.  Pretty sure it was chewed up as I probably got a hitchhiking mouse sometime during my travels this summer.  I bet that was one hell of a ride!!  I connected the two ends and the light is off.  Now just need to go back and solder together.  Thanks for all the help and comments.  A big thanks to CAV.  They really are an exceptional resource!!

Happy Flying, Sonny