---
title: "Reheater"
description: "A reheater is a tube bank in a boiler's convective pass that re-superheats steam returning from the high-pressure (HP) turbine before it enters the intermediate-pressure (IP) turbine. Reheat improves overall plant efficiency and reduces steam moisture content in the LP turbine stages."
canonical_url: "https://sylio.co/glossary/reheater"
last_updated: "2026-06-28T02:29:26.301Z"
---

A **reheater** is a tube bank in a boiler's [convective pass](/glossary/convective-pass-backpass) that re-superheats steam returning from the high-pressure (HP) turbine before it enters the intermediate-pressure (IP) turbine. Reheat improves overall plant efficiency and reduces steam moisture content in the LP turbine stages.

## Where it sits

In a typical utility-boiler convective pass, the reheater sits between the secondary [superheater](/glossary/superheater) and the primary superheater, in a temperature range that recovers heat efficiently without exceeding tube-metal limits. Some boilers have two reheat stages.

## Fouling

Reheater fouling follows the same pattern as the convective superheater: bonded ash on tube surfaces, occasional slag bridging in extreme cases. Outlet steam-temperature deviation is a leading symptom — falling reheat outlet temperature signals fouling reducing heat absorption.

## Cleaning

[Sonic horns](/glossary/sonic-horn) are well suited to reheater cleaning because the deposits are predominantly dry. Combined with periodic steam [sootblowing](/glossary/sonic-sootblower), they maintain reheater outlet temperature and protect the unit's [heat rate](/glossary/heat-rate).

## Related terms

- [Boiler](/glossary/boiler)
- [Superheater](/glossary/superheater)
- [Convective pass / backpass](/glossary/convective-pass-backpass)
- [Sonic horn](/glossary/sonic-horn)