Has anyone else had these problems with ZipFit liners?
Can anyone recommend any other liners for the boots?
Which liners might be less hot? (I seem to have the opposite temperature problem to most people!)
What is the material in the socks? That can make a big difference. I change into dry socks whenever it is I take my lunch break. I'm always amazed at how damp they are. Putting on a pair of nice dry socks at midday is a treat. Try it. It might solve your trouble and certainly won't hurt. If your feet are really sweating a lot it will also give your skin a chance to dry out.
Sounds like it might just be sweat rash - as in: the ZipFits are both closer-fitted and also simply don't absorb as much as your usual liners so the sweat stays on your skin.
I say 'just' but sweat rashes can be complicated by yeasts and bacteria, requiring antifungal/antibacterial creams. 'Daktacort' comes to mind here.
Zipfits are known to run warm (so much so that they're often recommended as a solution for cold boots!)
You're not the only person with this problem -- I always overheat on warm days, including my feet.
Definitely make sure you have wool or synthetic (usually polypropylene) socks, and change 'em at lunch if they are wet. Wet+friction will be no fun.
Some people also use spray-on antiperspirant on their feet. If you're sure it is sweating that is the problem, that's easy and cheap to try too.
If you feel like circulation is being cut off it's also possible the liner didn't form well to your foot/leg. You could ask the shop about having it reheated and molded again. One thing you can do is to wear thicker socks or two pairs of socks while they mold the liner, so it won't be as tight when you're just wearing one pair of thin socks.