Baxi Short Cycling / Oversized Boiler or Control Issue

Boiler cycles on and off rapidly, never runs for long, rooms take a long time to heat

Possible Causes

Boiler output too high for system, Flow temperature set too high, Poor system balancing, Faulty room thermostat placement (e.g. above radiator)

How to Fix / Troubleshooting

Safety first: Short cycling mainly affects efficiency and component life, not immediate safety.

User checks:

Reduce the CH flow temperature setting on the boiler to a moderate level (e.g. 65–70°C) if currently set to maximum.
Ensure the room thermostat is not located near a heat source or in direct sunlight.
Open more radiators to increase the load on the boiler.

Professional actions:

An engineer can rebalance the system, adjust boiler output settings (if available), and review control strategy.

Repair Difficulty

Easy 2/5