Split-range control
One controller output divided between two valves that share the range between them.
What it means
Split-range control drives two valves from one controller output, with each valve covering part of the range. The classic arrangement is heating and cooling: the output drives the heat valve across the lower part of the range and the cooling valve across the upper part, so the loop never has to switch controllers.
The split point — where control passes from one valve to the other — is a configuration choice with real consequences. An overlap leaves both valves open a little across the split, softening the handoff but wasting energy; a deadband has neither valve moving across the split, which is comfortable until the loop has to sit there.
Valve sizing makes or breaks the scheme. Two valves sharing one range are two process gains meeting at the split, and if the installed characteristics do not match, the loop is stable on one valve and unstable on the other.
Related
Glossary
Where this comes up
Last reviewed 2026-09-18.