Real Agent Cases

Get a furnace running until the repair visit with Gemini and a video

Posted
by andrewthornton (Hacker News)
Last checked
Method:
How we verify

Evidence: Described by posterThe person describes what happened in words, without screenshots or video.

Context: The prompt is quoted from the commenter's follow-up reply on the same Hacker News thread.

Outcome

With no repair appointment available for 2 days over the 2025 holidays, a Hacker News commenter filmed the furnace trying to start and gave the videos to Gemini. The commenter says it diagnosed the issue immediately and had them spin a small exhaust fan while the furnace tried to fire; it came on, and repeating that kept it working until the HVAC service arrived.

Agent

Gemini

Prompt Original prompt

Exact prompt as published in the source.

I have a furnace that will not heat when I reset the power to this unit. It makes some noise within its fan system for about three or four minutes and then I get an error light. Can you help me figure out what may be wrong here?
Optional stronger version

Our rewrite with extra checks. The poster didn't test it.

Let's work this out together. I'll tell you what I know, you suggest options and ask what you need, and we'll narrow it down step by step. Nothing gets booked, bought or sent until I say so.

Goal: Understand why my heating won't come on and what's safe for me to check while I wait for a technician.

What I'll share as we go:
- Furnace make/model and age (photo of the label)
- What happens at start-up: sounds, how long, error lights or codes
- A short video of the start-up attempt
- When my repair appointment is

Safety first: don't have me open or touch the gas valve, burner or flame area, or the electrical panel. If I smell gas or burning, tell me to leave the house and call the gas utility or a licensed technician.

Rules:
- Read the error code or light pattern from the label or manual first and tell me what it means.
- Only suggest checks a homeowner can do safely: thermostat settings, filter, power switch, condensate drain, vent blockages.
- For anything inside the burner or gas section, tell me to wait for the technician.
- Write down what to tell the technician so the visit is quicker.
- Check facts that can change (prices, opening hours, dates, availability, rules) against the official source, and tell me anything you couldn't verify.
- If you smell gas, see scorching, or the error points to the flame sensor, gas valve or heat exchanger, stop and tell me to call the gas utility or a technician now.

Output: Likely causes in order, the safe checks with results, and a short note for the technician.

You'll know it worked when: I know what's probably wrong, I've done only safe checks, and the technician gets a clear summary.

Before you finish: re-read my goal and constraints, check your answer against each one, and list anything you assumed or couldn't confirm.

Source

https://news.ycombinator.com/item?id=48417845

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