I am actually actually on vacation now-- only ten days though. I just watered well, and put some e bowls of water around them. I will water the minute I get home.
Orchids are tough plants. They can stand a mini drought, even if it's vacation caused.
I quickly killed my first two Phalaenopsis by covering the pot surface with wet sphagnum moss.
I'd ask a family member, friend or neighbour to come, check the home and water the plants. Otherwise bring your plants to somebody who isn't completely clueless.
I don't have massively hot weather here most of the time. But for 10 day type trips I've just watered everything on the day of leaving, and put damp spanish moss over all the mounts (and clumped them together).
Everything did fine and I just watered again as soon as I got home.
Other times I've done similar but put the mounts in the bath with a tiny bit of water (not touching them) in the bottom of the bath. The sides of the bath keep in the humidity caused by the water. That worked well as well.
I'm back from vacation today. I see a lot of new growth on my Catleyas. My oncidiums want a drink, but green tips on the roots, and the bud spike on one is larger. I think they got through it okay. In fact. I may start to water less.