UK trade guideBoiler Spares 4 min readUpdated 10 July 2026

How to Fix Ferroli F37 Fault Code (UK)

Ferroli showing F37 — Low pressure. UK diagnosis, likely spare (filling loop) and step-by-step reset.

Ferroli

What the code means

F37 on a Ferroli indicates low pressure. The boiler locks out to protect the heat exchanger and, on gas faults, to comply with the Gas Safety (Installation and Use) Regulations. Always reset to confirm the code is live, not historical.

Likely spare

The most common fix is the filling loop. Check the exploded diagram against the GC number on the data plate before ordering — Ferroli revised parts on Ferroli units mid-production.

Fix procedure

Top up.

Log the fault and reset. If the code returns within 24 hours, escalate to full electrical diagnosis with a manometer and multimeter.

Frequently asked questions

Can I reset F37 myself?
You can press the reset button up to 3 times. If F37 returns, the boiler needs a Gas Safe engineer — it is illegal to repair gas components without registration.
Is the part covered under warranty?
Ferroli standard warranty is 2–10 years depending on model. Registered installations get the full term. Check the sticker inside the case.
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