Tundish dripping: what the discharge means

Identify the visible fitting without touching it

A tundish commonly looks like a small open funnel or visible air break between discharge pipes. Its purpose includes making discharge visible. Nearby pipework can be confusing, and not every drip in a cupboard comes through a tundish, so describe the whole arrangement rather than assuming the name identifies the fault.

Take a photograph from a safe distance if the cupboard is dry and accessible. Include the cylinder label if you can read it without removing anything. Do not reach into the fitting, touch flowing water to assess temperature or remove covers to trace where pipes go.

Why the dripping needs assessment

Discharge can involve the pressure, expansion or temperature-control arrangements and their valves. Different faults can produce superficially similar drips. The professional needs to identify the source of discharge and the installed model, then assess the relevant components and operating conditions.

A slow drip is not a reason to wedge a valve shut or ignore it indefinitely. Equally, it is not proof that a completely new cylinder is required. The job is to find why water is passing through the discharge route and restore the appropriate operation without disabling its protective purpose.

When to treat it as urgent

Steam, unusually hot discharge, violent flow or signs of overheating need urgent professional advice. Keep people clear of the area. If the normal heat-source controls are safely reachable from a dry place, turn the heat source off and seek assistance. Do not close the water supply as a generic response to suspected cylinder overheating.

If water is escaping onto electrical equipment, do not touch wet switches or technical covers. Leave the area clear and explain the electrical involvement when seeking help. Do not wait for a routine service appointment where the situation presents an active hazard.

Timing is useful evidence, not a diagnosis

Note whether discharge is continuous, appears while water is being heated or follows a large hot water draw. Tell the professional if its frequency has changed. Use observations you already have; do not deliberately reheat a suspect installation to reproduce discharge.

Also report any loss of hot water, temperature changes or recent service work. A pause in dripping after using water does not demonstrate that the cause is fixed. An intermittent condition can return during the next cycle, and the professional should assess the pattern rather than only the moment of arrival.

Megaflo air gaps are not a universal explanation

Some Megaflo models have an internal air-gap expansion arrangement, while other cylinder designs use different provisions. That difference is why the equipment label and correct manufacturer instructions matter. Advice suitable for one model cannot simply be transferred to a tank that looks similar.

This guide does not give a valve-operating or recharge procedure. For unexplained or repeated discharge, request competent assessment. Restoring one aspect of an expansion arrangement without checking the cause can leave another fault unresolved, and manipulating an overheated or unfamiliar system is unsafe.

What the professional should establish

The assessment should identify which protective or control arrangement is discharging and why. Ask for the finding and proposed remedy to be explained, including any further tests or parts required. Replacing a valve solely because water passes through it can miss the condition making it operate.

Access to relevant components and the discharge route may be needed, not simply the front of the cylinder. Tell us about fixed shelves, boxing or a locked plant room. Do not remove fixed covers yourself in preparation; agree how the installation can be assessed and serviced safely.

Repair and routine servicing are different next steps

A current discharge problem is a fault enquiry. Once it is resolved, the cylinder’s routine maintenance schedule remains important. A service booking should explicitly mention the dripping so the required diagnosis is not mistaken for ordinary planned maintenance.

If replacement is recommended, ask whether the vessel has failed or whether another installation issue makes replacement appropriate. The proposal should connect the recommended work to the actual findings. Unvented cylinder competence is relevant; Gas Safe registration alone does not establish every qualification required for this work.

Report the problem and retain the outcome

Loyal Plumbers provides cylinder assessment and servicing throughout London and inside the M25, with 10 active vans and 24/7 operation. Send your postcode, cylinder make if known, what you can see and whether there is steam, unusual heat or electrical involvement. Those details help distinguish an urgent response from planned investigation.

After the visit, keep the explanation and repair record with the cylinder documents. Ask what normal operation looks like and what recurrence to report. Do not restart equipment that a professional has left isolated or restricted until the identified problem is resolved.

Use the form for written details first. It does not accept image uploads; the team can request useful photographs by email after your enquiry. Take photographs only where access is safe.