On the CAV website., it states
Using TKS® fluid, the system depresses the freezing point of moisture encountered in flight to at least the ambient temperature or down to -76°F (-60°C).
On one US site, I found this for the SR22:
There is a minimum operating temperature limitation for the TKS system in the SR, -30°F/-34°C
but others say -40C for the SR22, while others say -50C. However one pilot reported it not working at -37C.
Deice / anti-ice systems come with all kind of limitations that people ignore, at their own risk. For example, not opening the alt air down in visible moisture, or activating the boots below -40C in the PA46.
For a system with fluid, you probably have two temps to consider: one below which the fluid doesn’t work, and one below which the system dispensing the fluid does not work (maybe because the viscosity increases and the fluid doesn’t come out?).
So what does your POH say? When you bought the system you installed, did it have a POH supplement ?
TB20Sup10Sept04_281_29_pdf
Trinidad_1_TKS_ice_protection_system_pdf
Can’t see it in there.
Peter wrote:
However one pilot reported it not working at -37C.
TKS at -37C? was there any ice build up at those temps checking that the system works before he goes down?
Interesting that they consider -30C to be “abnormally low” ! And the fact it generates “high pressure” alerts that should be ignored points to an increase in viscosity. But that does not answer your question
Given ISA temperature -25°C in 20.000 foots 
and the ceiling of the TB20 being somewhere lower than that one could say that -30°C is in fact abnormally low.
I think the pump will run at “any” temperature but what they seem to be saying is that the liquid gets thicker.
Interesting why the SR22 is limited to -34C.
UdoR wrote:
Given ISA temperature -25°C in 20.000 foots
Right – but ISA temperature at seal level is 15°C and still we wouldn’t call 0°C at ground “abnormally low” during some parts of the year ;-)
Ibra wrote:
TKS at -37C? was there any ice build up at those temps checking that the system works before he goes down?
Obviously ice is very unlikely at -37C. The biggest downside of fluid based anti icing systems is, however, that they need to be activated well before you actually encounter ice. Therefore “coming from above” you not only need to test the system, but you actually need to activate it and have it running before you enter temperatures where you actually could find icing.
That is also the reason why the -40C limitation of the boots of the PA-46 is of completely different nature and consequences….
