No hot water from mixing valve

Hello. I bought a 'shower tower' over a year ago and finally hooked it up after gutting the bathroom and put it back together. The cold works great and the flow slows to a stop as I adjust all the way to hot. I removed the tower and have no problems with flow from supply lines. I've never taken a mixing valve apart. There are no markings on the valve to identify it. What's involved and any suggestions?
Mike

What is the brand of the tower?

There are shutoff valves on the shower body. Make sure they are both open all the way.

valve

The pressure balancing spool is probably stuck from being stored for that long. How to unstick it, if it is possible without replacing it, depends on the make and model of the control valve.