---
title: "Resetting the C04 for a smart modular unit"
slug: "resetting-the-c04-for-a-smart-modular-unit"
updated: 2025-08-22T15:35:40Z
published: 2025-08-22T15:35:40Z
canonical: "docs.calculus.group/resetting-the-c04-for-a-smart-modular-unit"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.calculus.group/llms.txt
> Use this file to discover all available pages before exploring further.

# Resetting the C04 for a smart modular unit

In exceptional cases, it may be necessary to reset the C04. To do this, perform the following actions.

## Instructions

Remove the front plate from the C04 by inserting a flat 2.5mm screwdriver into the recess and lifting the plate.

![](https://cdn.document360.io/94d0a983-5058-4b02-8d06-1228a999a7a1/Images/Documentation/image(12).png?sv=2026-02-06&spr=https&st=2026-11-11T13%3A40%3A38Z&se=2026-11-11T14%3A40%3A38Z&sr=c&sp=r&sig=et1ic0df75gV0kUp%2BPeN1E5M82dex1Bux7lbc5%2F1a3w%3D)

Press the **Reset** button.

![](https://cdn.document360.io/94d0a983-5058-4b02-8d06-1228a999a7a1/Images/Documentation/image(13).png?sv=2026-02-06&spr=https&st=2026-11-11T13%3A40%3A38Z&se=2026-11-11T14%3A40%3A38Z&sr=c&sp=r&sig=et1ic0df75gV0kUp%2BPeN1E5M82dex1Bux7lbc5%2F1a3w%3D)

## Hard reset

In some cases, it may be that the reset button, after you have used it, has not solved the problem. In this case, you can disconnect the connector from the small internal battery. This is stuck to the green connectors at the bottom. The battery is connected to a connector on the circuit board with red and yellow cables. This connector is located near the reset button.

![](https://cdn.document360.io/94d0a983-5058-4b02-8d06-1228a999a7a1/Images/Documentation/image(14).png?sv=2026-02-06&spr=https&st=2026-11-11T13%3A40%3A38Z&se=2026-11-11T14%3A40%3A38Z&sr=c&sp=r&sig=et1ic0df75gV0kUp%2BPeN1E5M82dex1Bux7lbc5%2F1a3w%3D)

Disconnect the battery and disconnect the power supply for at least 5 seconds. The power plug is located on the top of the C04, at the back.

![](https://cdn.document360.io/94d0a983-5058-4b02-8d06-1228a999a7a1/Images/Documentation/image(15).png?sv=2026-02-06&spr=https&st=2026-11-11T13%3A40%3A38Z&se=2026-11-11T14%3A40%3A38Z&sr=c&sp=r&sig=et1ic0df75gV0kUp%2BPeN1E5M82dex1Bux7lbc5%2F1a3w%3D)

After this period you reconnect the battery and the power supply.