A boiler breakdown is the last thing anyone wants—especially when it’s due to overheating or poor water circulation. One of the most common causes of this issue in Vaillant EcoTEC boilers is either a blocked canoe filter, a faulty pump, or a pressure sensor problem.

In this guide, we explain:

• Common signs of a circulation fault

• What to check yourself before calling for boiler repair

• When to call a Gas Safe engineer

 Symptoms of Poor Circulation or Overheating

If your boiler is:

• Cutting out

• Showing fault code F75

• Overheating or gurgling

• Running the pump but not heating properly…

…then circulation is likely restricted, and it’s time to inspect the pump and the canoe filter.

 Step-by-Step: Diagnosing a Circulation Issue in a Vaillant Boiler

 1. Check the Pump First

Before opening the boiler:

• Listen for a humming sound to confirm the pump is spinning

• If silent or inconsistent, the pump may have failed

In many cases, just the pump head needs replacing. It’s held by 4 screws and is a quick 15–20 min job for an engineer.

 2. Inspect the Pressure

Still not sure if it’s the pump? Try this:

• Check the pressure gauge on the front of the boiler (1.0–1.5 bar is ideal)

• If pressure looks good, press the reset button

• If it still doesn’t fire up, try adding a small amount of water through the filling loop

If it starts working after this, the issue is likely a faulty pressure sensor.

If not, the pump is likely the issue—no diagnostics needed, just replace it.

 3. Clean the Canoe Filter (Basket Filter)

If the pump is working, but you’re still seeing fault F75, the issue may be a blocked canoe filter (aka basket filter). This tiny mesh piece sits inside the brass block of the boiler and can easily clog over time.

Steps:

1. Drain the system and remove the boiler side panel

2. Remove the flow pipe to access the brass manifold

3. Take out the canoe filter, clean it thoroughly, or replace it if damaged

 A blocked canoe filter can stop water from circulating and trigger the F75 error.

 When to Call a Gas Safe Engineer

While some checks (like pressure and resetting) can be done by homeowners, opening the boiler and replacing internal components must be done by a Gas Safe registered engineer.

At Certificates4UK Ltd, we specialize in:

• Boiler repair and servicing

• Diagnosing circulation problems

• Replacing pumps, sensors, and filters

• Fixing Vaillant F75 and related errors

 Fast call-outs

 Fully qualified engineers

 Transparent pricing with digital certificate delivery

 Summary:

Problem Likely Cause Fix

Boiler cutting out / F75 error. Poor circulation. Clean canoe filter/check pump

Pressure okay, but still fails Pressure sensor fault.y Replace sensor

No sound from pump. Pump failure. Replace pump head

 Need Help With a Boiler Breakdown?

Don’t wait for the next cold morning. Whether it’s your Vaillant EcoTEC, Ideal Logic, or any other combi boiler, we’re ready to help with fast and professional boiler repair.

 Visit www.certificates4uk.co.uk

 Book a Gas Safe engineer today!