As the engineering Vice President you're looking for an answer... a functional answer... something that solves your headaches... and eliminates service calls... a true answer that’s better than anything else on the market... more versatile... and has value... a control with features our competitors don’t have... that makes purchasing agents, the production guys, contractors, owners, and technicians all happy... one that the sales guys can understand... and sell... and one that’s easy to implement into your drawings... one that makes your life easier... and you probably want the answer yesterday!
You can’t do much more to improve your existing systems. The vendors you have talked to only have generic "one product fits all" answers. You need to seriously look at customized new controls:
We design and manufacture customized electrical HVAC controls: