Error E193

Safety precautions:

1. If you smell gas, leave the property immediately and call the gas emergency number. Do not touch the boiler. 2. For all other checks, turn off the boiler before touching pipework or valves if you will be working where electrical or hot surfaces are exposed. Never remove the boiler casing or attempt electrical repairs unless you are Gas Safe registered. 3. Use gloves when touching radiators or pipework—parts can be hot. 4. If you are unsure or uncomfortable at any stage, stop and call a Gas Safe engineer.

Initial homeowner checks (safe and simple):

1. Note the error code and press the boiler reset button once (hold 3–5 seconds) and see if the boiler restarts. If it resets but the error returns, proceed to the checks below. 2. Check the boiler pressure gauge. If pressure is low (typically below 1.0–1.2 bar), repressurise the system using the filling loop until pressure is around 1–1.5 bar, following the boiler handbook. 3. Check the time/room thermostat and programmer to make sure they are calling for heat. 4. Check that any visible manual isolation valves on the pump, boiler flow/return pipes or on radiator TRVs are open. 5. Feel the flow and return pipes near the boiler when it is calling for heat (careful—may be hot). If the flow pipe is hot and the return is only slightly warm, circulation is probable; if both are similar and cool, the pump may not be moving water.

Further diagnostic steps you can try (still do not open the boiler casing):

1. Bleed radiators around the house to remove trapped air—start with the highest radiators first. After bleeding, recheck and adjust system pressure as required. 2. Check for cold spots on radiators which may indicate sludge or poor circulation to individual radiators. 3. Listen at the boiler while the heating is calling: a working pump normally makes a faint whirr. A loud grinding, clunking or total silence (when you expect a sound) can indicate a failing or jammed pump—note this and do not attempt to dismantle it. 4. If you have a magnetic filter on the system, inspect the external filter drain/cap for signs of sludge when drained (only do this if the filter has an accessible drain and you are comfortable with isolating that part of the system). If unsure, stop and call an engineer. 5. If you have thermostatic zone valves, check that their indicator shafts show open when heat is requested; stuck zone valves are a common circulation cause.

When to call a professional and what they will do:

1. Call a Gas Safe registered heating engineer if the error persists after the basic checks (reset, repressurise, bleed radiators, confirm valves). 2. A professional will safely isolate and open the boiler, test and, if necessary, remove/replace or free a seized pump, clean or replace system filters, check and clear blockages, check wiring and flow sensors, test zone valves and the PCB, and perform a full system flush if heavy sludge is present. 3. If your boiler repeatedly locks out on E193, arrange a service—continuing to reset repeatedly can mask an issue and risk component damage.

Final notes:

Do not attempt gas or electrical repairs yourself. E193 is primarily a circulation issue but can lead to overheating and repeated lockouts; prompt professional diagnosis is the safest course if simple homeowner checks do not clear it.