D.8 Low
Your boiler is working correctly and is simply indicating that your external thermostat or programmer is asking it to provide heat.
Technical description: External controls heat demand
Typical repair cost: £0 (including labour)
DIY fix possible
Check if your room thermostat is set to a high temperatureEnsure your central heating programmer or timer is switched to 'On'Check if your hot water cylinder thermostat is calling for heat
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.8 — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.