HIU Service, Repairs & Maintenance in London

Most HIU repair costs depend on the fault, whether parts are required, and how long diagnostics take. We provide an upfront quote once we understand the symptom and the HIU make/model. For common HIU faults, fixed-price options may be available, and any parts costs are confirmed in writing before fitting.

This is common on HIUs because heating and hot water are controlled separately. Causes can include control or valve faults, blocked filters, incorrect settings, thermostat/programmer issues, or flow/temperature problems from the heat network. A proper diagnosis checks the HIU’s components and confirms whether the primary supply is correct.

Yes. Annual HIU servicing helps prevent breakdowns, improves performance, and reduces the risk of blockages and component wear. Many manufacturers also expect regular servicing to maintain best performance and, where applicable, warranty conditions. A service is usually far cheaper than an emergency repair.

A HIU service typically includes inspection, cleaning filters/strainers, checking pressures and temperatures, testing valves and sensors, verifying hot water and heating performance, and identifying early signs of wear or restrictions. You should also receive a written summary of findings and recommendations, especially for managing agents and landlords.

Yes. Availability depends on location, access, and the nature of the issue, but we prioritise loss of heating or hot water where possible. When you contact us, sharing the HIU brand, any fault code, and a short symptom description helps speed up diagnosis and attendance planning.

If safe to do so, stop using the unit, protect electrics, and contact an engineer. Leaks can come from valves, fittings, pressure relief discharge, or internal components, and pressure drops often indicate a leak or expansion/pressure control issue. Avoid repeatedly topping up without diagnosis, as it can worsen damage over time.

Take a photo of the fault code and note when it appears (on hot water, heating, or both). You can try one reset if your manufacturer guidance allows it, but do not keep resetting repeatedly. Fault codes are useful for faster diagnosis, but the underlying cause still needs testing on-site.

We work on a wide range of Heat Interface Units used across London, including common manufacturers found in apartment blocks and communal heating schemes. If you share a photo of the HIU label or the model name (for example Danfoss, Evinox Modusat, Intatec, Altecnic, Meibes, Caleffi), we can confirm compatibility and likely parts availability.

Repair is usually best when the fault is isolated and parts are available. Replacement may be recommended if the HIU is repeatedly failing, parts are obsolete, performance is poor due to internal wear, or repair costs approach replacement value. We will advise the most cost-effective option based on diagnosis and provide a clear quote for either route.

Yes. Planned maintenance (PPM) helps reduce breakdowns, improves resident satisfaction, and creates predictable budgeting. A maintenance plan can include scheduled servicing, reporting, priority response options, and clear records by flat or plot number, which is particularly useful for managing agents, housing associations, and developers.