Track HVAC maintenance agreements and automate reminders with Google Sheets, Gmail, and OpenAI
Ready for 3.0Ready for 3.0. This template uses no nodes that n8n 3.0 removes. No removed nodes, versions or helpers found. Static check, last run 2026-10-19.
What this workflow does
This AI workflow has 25 nodes and runs when an HTTP POST request hits its webhook URL (plus 2 other triggers). Along the way it connects Gmail, OpenAI Chat Model and Google Sheets.
How it runs
Trigger: When an HTTP POST request hits its webhook URL (plus 2 other triggers).
- Normalize New Agreement (Edit Fields (Set)): sets 14 fields: agreement_id, customer_name, customer_email…
- Read Agreements (Google Sheets): uses Google Sheets
- Read Agreements for Review (Google Sheets): uses Google Sheets
- Validate Agreement (If): checks a condition and branches into true / false
- Flag Due Agreements (Code): runs custom JavaScript code
- Collate Agreement Stats (Code): runs custom JavaScript code
- Draft Welcome Email (AI Agent): runs an AI agent, with model: Welcome Draft Model
- Alert Office on Invalid Entry (Gmail): uses Gmail
- Draft Reminder Email (AI Agent): runs an AI agent, with model: Reminder Draft Model
- Draft Weekly Review (AI Agent): runs an AI agent, with model: Weekly Review Model
…plus 9 more steps. See the full node list below.
Services it uses
Before you upgrade to n8n 3.0
Nothing in this workflow is removed in n8n 3.0, so it should import and run after the upgrade.
Nodes used (9)
- Webhook
n8n-nodes-base.webhook - Edit Fields (Set)
n8n-nodes-base.set - If
n8n-nodes-base.if - Gmail
n8n-nodes-base.gmail - AI Agent
@n8n/n8n-nodes-langchain.agent - OpenAI Chat Model
@n8n/n8n-nodes-langchain.lmChatOpenAi - Code
n8n-nodes-base.code - Google Sheets
n8n-nodes-base.googleSheets - Schedule Trigger
n8n-nodes-base.scheduleTrigger
From the author
Maintenance agreements only pay off when someone remembers the next service date. This n8n workflow takes a new agreement from a webhook, has gpt-6-luna write the welcome email, logs it to Google Sheets, then handles the follow-up: a daily check for services…