Alert if thermostat 'bounces'

Configuration
1

Facing a somewhat exotic automation case. Would like to automate alerts if/when this odd scenario happens.
The thermostat (a Nest ‘e’) has been logged as calling for heat, then about 30 seconds later (and only sometimes) dropping the call and immediately reinitiating it, then holding the call on for the usual heating duration. (This has the effect of triggering an alert in the furnace’s internal module, since a heat-off-heat in rapid succession isn’t normal.)
I have an ESPHome device at the furnace which monitors the heat/fan/cool lines (using 24VAC relays driven by the thermostat, in parallel to the furnace), reporting the states of each to HA - as binary_sensors - at all times.
Yes, this problem is probably due to a defect in the thermostat firmware, but I’d like HA to help me catch it in the act :wink:

So, the goal is to compose a simple automation that triggers: If heat is called-for, but has been off for less than 1 minute, alert.

Is there a simple way to create such an automation/trigger?

2

Set a date time helper to now() when the heat is turned off and check it when heat is attempted to be turned on.

1 Like
3

A fantastic idea. Thanks @WallyR
My initial, crude implementation of it looks like 2 automations. One sets the helper whenever heat turns ‘off’. The other looks like this:

alias: Alert if heat-call hiccups
description: ""
trigger:
  - platform: state
    entity_id:
      - binary_sensor.hvac_heat
    to: "on"
condition:
  - condition: template
    value_template: >-
      {{ as_timestamp(now()) -
      as_timestamp(states('input_datetime.heat_last_off')) < 500 }}
action:
  - service: notify.persistent_notification
    data:
      message: heat wasnt off long enough
mode: single