CTL26 doesn't like cold temperatures

[Wiigian]

Not sure if this is an actual tool problem, or a feature, here goes:

I was drilling a 1" hole though my basement concrete wall, using a Bosch rotary hammer drill connected to the power outlet of my CTL26. The CTL hose end was placed near the hole to collect most of the dust.
Right after I broke through the wall with the drill bit, the CTL motor started to dip in rpm for a second or two, and then got back up to speed, several times
At first, I thought this was maybe due to the changed electrical load caused by the hammer drill, but more testing showed that this happened every time the CTL sucked cold air from outside through the 1" hole that I just had drilled.

The ambient temperature in my basement was around 20℃/68°F, and the outside temperature was around -5℃/23°F.

Should I send it in for repair, or could this temperature difference trigger some kind of safety feature that I have not thought of?
Anyone with a similar experience?

 

[notenoughcash]

may be because the air is denser, but i doubt that would have made that much difference.  not much experience with a ctl26, or even masonry work with any festool vac.

 

[Eorlingur]

It sounds like something that I could try the next time I am in the shop, if I can get the shop warm enough. The cold air is almost 10% more dense so it is plausible that the motor would drop in RPM when the load gets higher and then compensate. It probably does that when it sucks debris as well, but then the noise from the debris masks the noise from the motor.

 

[mino]

The air density difference is about 10% (300K/270K) which should not be very noticeable.

But the drop in temperature can affect the electronics/sensors measuring the fan/motor speed getting them "out of balance".

Probably a bit from each adding up. Will be interesting to test this.