Mechanical Engineer

Job Title: Mechanical Heating & HIU Engineer

Location: Field Based – London & Greater London

Job Type: Full-time, Permanent

Hours: 07:30 – 16:30 (excluding 30-minute lunch break)

Why Join Us

Join a highly respected engineering team working within one of the most technically challenging and rewarding environments. Your work will directly support critical healthcare infrastructure, ensuring safe and reliable services for patients and staff.

We offer excellent earning potential through regular overtime, structured training programmes to expand your technical expertise, and genuine opportunities for career progression. Whether you are looking to deepen your steam and heating knowledge, gain specialist certifications, or move into leadership, we will support your development every step of the way.

Role Overview

We are seeking a skilled and motivated Mechanical Heating & HIU Engineer to join our engineering team. The works are primarily based across sites in South & West London. This role is ideally suited to an engineer with experience working on commercial heating and HIU systems who is confident carrying out planned maintenance, reactive repairs, fault diagnosis, component replacements, and system upgrade works.

You will play a key role in maintaining, repairing, and improving essential heating and HIU infrastructure. The position offers a varied workload across multiple sites, plant rooms, and communal heating systems, including planned maintenance, reactive breakdown response, remedial works, and infrastructure improvement projects, with strong operational support from our wider engineering and management team.

We are committed to investing in our engineers through ongoing accredited training, overtime opportunities, and clear career progression pathways, including the potential to progress into Lead Engineer or Supervisory roles.

Working Pattern & Coverage

• Field-based role covering Northwest, West and South London.
• Travel between sites will be required depending on operational priorities and workload.
• Core working hours: 07:30 – 16:30 (excluding a 30-minute lunch break).
• Regular overtime opportunities available, including evenings and weekends.
• Participation in a 24-hour call-out rota is required. Call-outs are typically low volume, with a competitive standby allowance and enhanced rates for attended callouts.

Key Responsibilities

• Carry out planned preventative maintenance (PPM), servicing, fault finding, and reactive repairs on commercial heating, domestic hot water, and HIU systems.
• Respond to emergency breakdowns and service interruptions, restoring heating and hot water services through effective diagnosis and repair of HIU, plant room, and distribution system faults.
• Maintain, repair, install, and modify LTHW, MTHW, domestic hot water, and steam systems.
• Service and maintain plant equipment including plate heat exchangers, pumps, motorised valves, safety valves, gauges, controls, and associated mechanical equipment.
• Remove, inspect, clean, descale, and refit calorifier bundles, plate heat exchangers, and associated components.
• Carry out replacement and upgrade works on HIUs, pumps, valves, actuators, controls, plate packs, gauges, pipework, and other mechanical system components.
• Locate, diagnose, and repair leaks on heating, hot water, and associated pipework systems, implementing both temporary and permanent repairs as required.
• Undertake mechanical installation, modification, and re-pipe works using steel, stainless steel, galvanised steel, copper, and ABS pipework systems, including threaded, crimped, and welded fittings where applicable.
• Diagnose system faults and performance issues, identifying remedial works and providing recommendations for repairs, upgrades, and lifecycle replacement projects.
• Support planned refurbishment, upgrade, and infrastructure improvement projects
• Attend occupied residential, commercial, and healthcare premises to investigate and resolve heating and hot water issues whilst maintaining high standards of customer service and professionalism.
• Ensure all work is completed safely and in accordance with health & safety legislation, RAMS, permits to work, site procedures, and client compliance requirements.
• Maintain accurate service reports, maintenance records, and documentation using company digital systems.
• Communicate effectively with supervisors, management, clients, and end users regarding system status, risks, recommendations, and completed works.
• Work independently or as part of a wider engineering team to deliver maintenance, reactive, and project works efficiently and to a high standard.

Skills, Knowledge & Experience

Essential

Proven experience servicing, fault finding, repairing, and replacing Heat Interface Units (HIUs), including controls, actuators, plate heat exchangers, strainers, heat meters, and associated components.

Proven experience as a Mechanical Heating Engineer within commercial, industrial, or communal heating environments.

Strong experience working within commercial plant rooms and heating systems.

Knowledge and practical experience of LTHW, MTHW, and domestic hot water systems, including operation, maintenance, and fault diagnosis.

Experience maintaining and repairing pumps, valves, calorifiers, plate heat exchangers, and associated mechanical plant.

Ability to diagnose faults, undertake reactive repairs, and carry out mechanical installations and system modifications.

Experience diagnosing and repairing heating and hot water system leaks and associated distribution pipework.

Strong understanding of health & safety legislation, safe systems of work, permits to work, and RAMS.

Good communication, customer service, and reporting skills.

Relevant mechanical qualification (NVQ Level 2/3 in Mechanical Engineering, Plumbing & Heating, or equivalent).

Full UK driving licence.

Desirable

Experience working on communal heating networks serving residential developments.

Steam system maintenance and fault-finding experience.

PSSR Competent Person (CP) or Authorised Person (AP) certification.

Experience delivering plant room refurbishments, system upgrades, and infrastructure improvement projects.

Experience producing remedial recommendations and supporting quotation or lifecycle replacement activities.

Benefits

Overtime paid at enhanced rates.

Training & Development opportunities

Standby allowance and additional overtime opportunities.

Phone, tablet, fuel card and parking apps.

Full induction and mentoring programme.

Ongoing accredited training and development opportunities.

Company pension scheme