Hi there, Please try this flow.
[{"id":"0338dda6747f35f6","type":"server-state-changed","z":"51045e07.bbf87","name":"binary_sensor.parasol","server":"d177950.2a5aa68","version":3,"exposeToHomeAssistant":false,"haConfig":[{"property":"name","value":""},{"property":"icon","value":""}],"entityidfilter":"binary_sensor.parasol","entityidfiltertype":"exact","outputinitially":false,"state_type":"str","haltifstate":"off","halt_if_type":"str","halt_if_compare":"is","outputs":2,"output_only_on_state_change":true,"for":"10","forType":"num","forUnits":"minutes","ignorePrevStateNull":false,"ignorePrevStateUnknown":false,"ignorePrevStateUnavailable":false,"ignoreCurrentStateUnknown":false,"ignoreCurrentStateUnavailable":false,"outputProperties":[{"property":"payload","propertyType":"msg","value":"","valueType":"entityState"},{"property":"data","propertyType":"msg","value":"","valueType":"eventData"},{"property":"topic","propertyType":"msg","value":"","valueType":"triggerId"}],"x":310,"y":2220,"wires":[["402dd20372f41777"],[]]},{"id":"402dd20372f41777","type":"api-call-service","z":"51045e07.bbf87","name":"group.heaters","server":"d177950.2a5aa68","version":3,"debugenabled":false,"service_domain":"homeassistant","service":"turn_off","entityId":"group.heaters","data":"","dataType":"jsonata","mergecontext":"","mustacheAltTags":false,"outputProperties":[],"queue":"none","x":550,"y":2220,"wires":[[]]},{"id":"d177950.2a5aa68","type":"server","name":"Home Assistant","version":1,"legacy":false,"addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true,"cacheJson":true}]
It looks like this
![image](https://community-assets.home-assistant.io/original/3X/b/7/b7b15210256c7489c5f01a88cc6919c7b5f2c475.png)
If this doesnot work you will have to share the state of the binary sensor and your flow in nodered to have a better look