Verified boiler fault code

Keston 50 Fault Code (Heat 2)

Blocking due to no central-heating water flow.

Safety disclaimer

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Fault code summary

Manufacturer
Keston
Fault code
50
Fault type
Circulation, Central heating
Severity
blocking
Reset
The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.
Applicable models
Keston Heat 2 45, Keston Heat 2 55, Keston Heat 2 45P, Keston Heat 2 55P

Quick answer

Blocking due to no central-heating water flow.

What does this fault code mean?

Blocking due to no central-heating water flow.

Common causes

  • No CH water flow.

Symptoms

  • The boiler fault screen shows code 50 and a blocking condition.

What can the homeowner safely check?

  • Record the code and contact a qualified engineer.

Boiler reset information

The Heat 2 fault screen shows a Press Reset prompt; 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 pump operation, system valves, air and primary circulation.

Applicable boiler models

Related fault codes

Manufacturer documentation

Keston Heat 2 Installation & Servicing Manual

FAULT FINDING MENU: Blocking due to no CH water flow — code 50.

Last verified

2026-09-12

Frequently asked questions

What does Keston 50 mean?

Blocking due to no central-heating water flow.

Can I reset a Keston 50 fault?

The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.