Mixet is owned by "Alsons" they have a web-site...you have either installed the cartridge in-correctly or you have installed the wrong cartridge. Very common to have a "cross-connection" between the hot and cold in either of the instances. erik

I've installed several Mixet shower valves including the commercial variety with the builtin stop valves to allow cartridge change without turning off the water anywhere else. On all the Mixets I've seen you would have to move the cartridge to either cold or hot before shutting off the flow if you intend to prevent crossover. I have three of the Mixet showers at my home and crossover has not been a problem even though I have a hot recirculation loop from the master bath to the water heater in the garage. We leave the valves in a mixed position pretty consistently. Again, when you need to stop crossover just move the cartridge to cold or hot (90 degrees from center warm position).

Hot water return-line has no bearing in a cross connection/bypass if installed correctly...One should not have to turn the cartridge to either the hot completely or the cold completely to prevent bypass if the cartridge is in good working order and it is indeed the correct cartridge for the model valve. You have solved your own problem with the way you operate your own..perhaps it will help others. erik

btw......nice to see that some are reading "old threads". Most answers can be found if one is willing to spend a little time going back to review past issues. erik

I've got a Mixet shower fixture -- http://www.plumbersurplus.com/pdf/02336.pdf. I'm having a problem with little to no hot water coming out of the faucet or showerhead. Does the pressure balancing spool need to be adusted or set in a certain rotation (it's 2-pc, inner piece slides into the outer pc)? I turned off both the hot and cold water spring checks (see pdf doc) then I removed the Mixet stem. I turned the cold water back on and the flow was fine out of the pipe of the Mixet housing unit. I then turned the cold water off and turned the hot water back on but no hot water flowed. Next I turned the hot water off, removed the balance spool, reinstalled w/o it's inner piece and turned the hot water back on. The hot water flowed fine. The inner pc of the pressure balancing spool slides in/out and rotates easily within the outer pc of the pressure balancing spool -- appears to me to be self-adjusting. It doesn't appear to me that the stem physically interacts with the balancing spool -- other than via the water pressure. I'm reluctant to leave out the inner pc of the pressure balancing spool as a permanent fix -- not sure if it'll blow out seals of the stem. Any thoughts? I did a google search but wasn't able to find anything on it.