---
title: "Setting up a CCR plan"
description: "Choose the breathing mode when the plan is created, then add the diluent and bailout gases the closed-circuit planner needs before it will run."
---

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

# Setting up a CCR plan

import { NewPlanDialog } from "@/components/react/ModalScreens";

Breathing mode is a property of the plan, set when the plan is created. In the
**New dive plan** dialog, the **Breathing Mode** control offers **Open Circuit**
and **Rebreather (CCR)**. Choosing Rebreather (CCR) puts the whole plan on the
closed-circuit path; there is no per-dive toggle further in.

## What changes in CCR mode

- The Plan step's section rail gains a **CCR** entry, between Environment and
  ICD Safety, holding **Setpoint Settings**, **Bailout SAC Rates** and
  **Scrubber**.
- The gas wizard offers four closed-circuit roles in place of bottom, travel and
  deco gas: **Onboard Diluent**, **Offboard Diluent**, **Bailout** and
  **Diluent + Bailout**. See [Diluents](/ccr/diluents).
- Every step of the dive is planned on the loop mix implied by the active
  setpoint rather than on a cylinder gas. Gradient factors, algorithm, stop
  increment and ascent rates are unchanged; see
  [Decompression settings](/planning/decompression).
- If [air breaks](/planning/air-breaks) are enabled, a **Break Setpoint** field
  appears. Set it and the planner holds the loop there for the break instead of
  switching to the break gas.
- The Review step gains a **Bailout** control above the profile chart in the
  Overview, Schedule, Gas and Tissues views. See
  [Bailout scenarios](/ccr/bailout).

## The smallest plan that runs

Two gases, in two roles.

- **One Onboard Diluent**, mandatory. Without it the planner refuses to run and
  reports `CCR mode requires an Onboard Diluent gas to be configured.`
- **At least one open-circuit-capable gas**, in the **Bailout** or **Diluent +
  Bailout** role. The loop schedule computes without one; bailout planning does
  not, and returns `Add an OC bailout or diluent bailout gas to plan bailout
  scenarios.` in place of the scenario picker.

> **Caution**
>
> The planner does not verify that a bailout gas exists before producing a loop
> schedule. A CCR plan can therefore look complete, with profile, stops, runtime
> and TTS all present, while carrying nothing to bail out onto. The bailout
> picker's error state on the Review step is the only place this shows.

The dive the rest of this section uses is 55 m for 30 minutes on a 21/35
diluent, with 21/35 as diluent bailout and 50 % as an open-circuit bailout gas,
setpoints 0.7 on descent and 1.3 from 30 m.

## Next

- [Setpoints](/ccr/setpoints) covers the three you always have and the ones you
  add.
- [Diluents](/ccr/diluents) deals with onboard, offboard and diluent bailout.

Source: https://docs.divelogic.ai/ccr/setup/index.mdx