Does anyone know if the Uponor manifolds can be installed upside down? I've installed 3 Tru-Flow manifolds in my house for radiant heat, and will be installing more radiant over the summer, but it would be easier based on the conifg of my boiler room to install these upside down. Uponor says they can't be installed this way, but I've seen them this way on This Old House. Any Thoughts?

Happy Holidays