The ZR 011 houses two separate thermostats, allowing the independent control of heating and cooling or other equipment. These color‑coded devices are available in NC/NO or NO/NO configurations, with separate adjustable setting ranges. The NC thermostat provides a normally closed contact (red ‑ opens on temperature rise) for regulating heaters or for switching signal devices when temperature has fallen below the minimum value. The NO thermostat provides a normally open contact (blue ‑ closes on temperature rise) for regulating filter fans, heat exchangers, cooling devices or for switching signal devices when temperature limit has been exceeded.