What is ZC and ZR terminals?
When an aquastat has the ZC and ZR terminals, the ZC is connected to the low temperature switch of the aquastat and to the ZC terminal of the Taco control. The ZR is a 120 Volt supply to the burner circuit to fire the boiler, but this goes through the high limit switch to control the boiler water temperature.
How do I adjust my Honeywell Electronic aquastat?
To discourage unauthorized changing of Aquastat® settings, a procedure to enter the adjustment mode is required. To enter the adjustment mode, press the UP, DOWN, and I buttons simultaneously for three seconds. Press the I button until the feature requiring adjustment is displayed: HL – High Limit.
What temperature should aquastat be set at?
In most cases, the high-limit temperature setting on an aquastat should be between 180 and 200 degrees Fahrenheit. If the aquastat is set at 200 degrees Fahrenheit as the high-limit setting and the pressure valve begins to leak, set the temperature back to 195 degrees Fahrenheit.
What is the differential setting on an aquastat?
When boiler temperature is rising: on an aquastat control, the “DIFF” or differential control dial specifies the amount above the LO or “Low Limit” to which boiler temperature must rise before the burner will turn off and the circulator will be allowed to run.
What does cold start boiler mean?
Cold-start unit: This is any heating appliance that does not maintain temperature, but does produce domestic hot water. The concept allows the boiler to remain cleaner throughout the operating year and actually accelerates recovery during extended periods of domestic hot water draw.
How do I reset my Honeywell Aquastat?
When the temperature of the controlled medium drops to the high limit setting minus differential, push the manual reset button and the system should be operative again. Reset control to proper high limit setting.
How do I test my Honeywell Aquastat?
How to Conduct Basic Boiler Aquastat Controller Tests:
- Turn thermostat down – Turn the wall thermostat all the way down so it is not calling for heat.
- Check incoming voltage –
- Check the low voltage transformer output:
- Check thermostat switch terminals:
- Check burner power terminals:
- Check circulator terminals:
