If you’ve just installed an Espar or Eberspacher heater and are seeing a “No Heater” error on the EasyStart Pro, you’re not alone. Whether you’re troubleshooting an Espar no heater code or unsure how to fix an Eberspacher no heater error, this guide will walk you through the most likely cause and the simplest fix.

If you’ve just installed an Espar or Eberspacher heater and are seeing a “No Heater” error on the EasyStart Pro, you’re not alone. Whether you’re troubleshooting an Espar no heater code or unsure how to fix an Eberspacher no heater error, this guide will walk you through the most likely cause and the simplest fix.

Here’s how one customer solved the issue in just a few minutes.

A van owner completed their install of an Espar AS3 D2L heater. When they powered up the EasyStart Pro controller, the screen showed “No Heater”, and nothing happened. The system looked fine, but something was off.

Newer Eberspacher heaters include two power connections:

• A thick red wire that powers the heater
• A thin red wire that powers the controller

If the controller wire is connected before the main heater wire, the controller powers up and tries to communicate to the heater - but it can’t find the heater’s ECU, so it shows “No Heater”.

We asked the customer to do the following:

1. Remove both fuses
2. Reinsert the 20A fuse (thick red wire), wait a few seconds and then insert the 5A fuse (thin red wire)

Once reconnected properly, the controller detected the heater, and everything worked as expected.

This issue isn’t limited to the AS3 D2L. It applies to any second or third generation Espar / Eberspacher heater using the EasyStart Pro, including Airtronic and Hydronic heating systems.

If you’ve installed one of these and see a “No Heater” message, start by checking the wiring sequence.

If your system was working and suddenly shows “No Heater”, the wiring order is likely not the cause. In that case, check for:

• Weak or unstable power supply
• Loose, corroded, or damaged connectors
• Wiring damage
• A fault in the heater’s ECU

Always follow the installation manual, and when in doubt, ask. Heatso support is here to help you get it right the first time.

If your EasyStart Pro shows “No Heater” error code, double-check your installation sequence. Make sure your heater’s power supply is connected directly to the main battery, then power up the heater first, then the controller. In most cases, that’s all it takes to get your Espar heater up and running.