Main Heating E20 Fault Code (Eco Elite System)

Safety disclaimer

Fault code summary

Manufacturer

Main Heating

Fault code

E20

Fault type

Temperature sensor, Central heating

Severity

Not specified

Reset

Not specified

Applicable models

Main Eco Elite 24 System ErP, Main Eco Elite 28 System ErP

Quick answer

Central-heating NTC fault.

What does this fault code mean?

Central-heating NTC fault.

Common causes

• Central-heating NTC fault.

Symptoms

• The facia displays E20.

What can the homeowner safely check?

• Record the displayed code and consult the user instructions.

Boiler reset information

Reset information was not provided in the verified manufacturer source. Do not repeatedly reset an unresolved fault.

When should I call an engineer?

Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.

Engineer diagnosis

• Investigate the central-heating NTC sensor and wiring.

Applicable boiler models

• Main Eco Elite 24 System ErP
• Main Eco Elite 28 System ErP

Related fault codes

• E110 — Eco Elite System

  Safety thermostat operated.

  Read fault code
• E119 — Eco Elite System

  Water-pressure switch not operated; the manual states this is shown below 0.5 bar primary-water pressure.

  Read fault code
• E125 — Eco Elite System

  Circulation fault in the primary circuit.

  Read fault code
• E131 — Eco Elite System

  Interruption of power supply while in fault mode.

  Read fault code
• E133 — Eco Elite System

  Interruption of gas supply or flame failure.

  Read fault code
• E160 — Eco Elite System

  Fan or fan-wiring fault.

  Read fault code
• E28 — Eco Elite System

  Incorrect PCB fitted.

  Read fault code
• E50 — Eco Elite System

  Hot-water NTC fault.

  Read fault code

Manufacturer documentation

Table Of Error Codes: E20 — Central Heating NTC Fault.

Last verified

2026-09-12

Frequently asked questions