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Developers · Main Contractors · Managing Agents

HIU Commissioning & Servicing Contracts

Block-wide Heat Interface Unit commissioning and annual servicing across Greater London — delivered to programme, recorded per unit, and handed over with documentation that stands up to scrutiny.

Request a Proposal 020 3951 5133
WRAS Certified£5m Public Liability5.0 Stars · 43 ReviewsGreater London

Quick answer

Collide Group carries out HIU commissioning for new-build and retrofit blocks across London, and annual HIU servicing contracts for buildings already in occupation. Every unit is commissioned or serviced to a documented checklist, recorded individually, and collated into a block-level register or compliance pack. We are a WRAS-certified Heat Interface Unit specialist based in Northolt, covering all of Greater London, with £5,000,000 public liability insurance and coverage of all major HIU brands.

Who We Work With

Contract HIU work for the people responsible for getting a block signed off — and for keeping it compliant afterwards.

Developers & Project Directors

Units commissioned, recorded and signed off in time for practical completion and handover.

Main Contractors & M&E

A specialist subcontractor for the HIU package, working to your programme and commissioning specification.

Managing Agents & Block Managers

One annual contract covering every flat in the block, with resident access handled for you.

Housing Associations & Councils

Programmed servicing across estates, with reporting that stands up to audit.

Heat Network Operators & ESCOs

Return temperature and heat meter verification that protects network efficiency and billing accuracy.

Facilities Managers

Planned maintenance cycles and priority callout cover under a single point of contact.

HIU Commissioning for New-Build & Retrofit Blocks

An HIU that has been installed but never properly commissioned will pass a visual inspection and still deliver poor hot water performance, high return temperatures and resident complaints within weeks of occupation. Commissioning is what proves each unit actually performs — and what gives you the records to demonstrate it.

Pre-commissioning checks — system cleanliness, strainer and filter condition
Pressure testing and isolation valve verification
Differential pressure control valve (DPCV) setting
Primary flow and return temperature verification
Domestic hot water setpoint, temperature rise and stabilisation timing
Flow rate measurement at outlets in litres per minute
Return temperature checks that protect heat network efficiency
Keep-warm and standby mode configuration
Heating circuit balancing, PICV setting and actuator checks
Heat meter commissioning, serial recording and comms verification
Per-unit commissioning record sheets and a block-level register
Snagging list, re-visits and formal close-out
DanfossSAVCaleffiSwitch2Alfa LavalHeatwebThermal IntegrationRedan

Annual HIU Servicing Contracts for Occupied Blocks

Once a block is occupied the job changes: the engineering is routine, and the hard part is access, consistency and paperwork. We run the whole cycle — booking residents, attending, reporting per unit and handing you a compliance record at the end.

Annual service to a 30-point checklist on every unit
Strainer clean and plate heat exchanger inspection or descale
Valve, actuator and control verification
Temperature, flow and return performance testing
Written service report per unit after every visit
Resident appointment booking, reminders and rescheduling
No-access tracking and re-attendance reporting
Block-level compliance pack at the end of each cycle
Priority callout rates for units under contract
Mixed-brand estates covered under one agreement

Running an occupied block? See our bulk HIU servicing contracts page for the full contract scope, or read what is covered in a single annual HIU service.

What You Get at Handover

Documentation is usually what holds up a handover — not the engineering. We issue it as a single pack.

Per-Unit Commissioning Records

A completed record sheet for every flat, showing the settings and readings achieved at commissioning.

Block Commissioning Register

A single register covering the whole building, so nothing is missing when the file is reviewed.

Heat Meter Schedule

Meter serial numbers and opening readings recorded per unit, ready for the billing provider.

Photographic Record

Photographs of installed units and meter readings, filed against each flat.

Snag List & Close-Out

Outstanding items logged, re-visited and signed off rather than left open at handover.

RAMS Before Mobilisation

Task-specific risk assessments and method statements issued to your team before we start on site.

Why Project Teams Choose Collide

HIU and MVHR specialists — this is what our engineers do every day, not a sideline to general plumbing
WRAS certified, with £5,000,000 public liability insurance and certificates available on request
Documented Health & Safety policy and task-specific RAMS issued before mobilisation
All major HIU brands covered, so mixed-brand estates stay under one contract
5.0 stars from 43 Google reviews across residents and property professionals
London only — our engineers are local, so snagging visits and returns happen quickly
Years of specialist HIU experience across social housing, new-build and private blocks
One point of contact from survey through to handover or contract renewal

How We Mobilise a Block Contract

01

Enquiry & Scope

Send us the unit schedule, drawings or a simple flat count with HIU brands. We will tell you quickly whether it is a job we can take on and when.

02

Site Survey

We attend site, confirm unit types and access arrangements, and check the network is ready for commissioning.

03

Fixed Proposal

A written proposal with scope, per-unit rate, programme and deliverables. No open-ended day rates.

04

Mobilisation

RAMS issued, access plan agreed, phasing confirmed with your site team or resident liaison.

05

Delivery & Reporting

Works carried out with progress reported as we go, so you always know the completed unit count.

06

Handover

Records, register and snag close-out issued as one pack for your O&M file or compliance record.

Pricing & Proposals

HIU Commissioning

Quoted per project

Priced after a site survey, based on unit count, unit type, access and the commissioning specification you need us to work to. A fixed per-unit rate in the proposal — not an open-ended day rate.

Block Servicing Contract

Quoted per block

Annual planned servicing across the whole block, with the per-unit rate improving as the unit count rises. Includes resident access coordination and full reporting.

Send us a unit schedule or a flat count and we will come back with a written proposal, a programme and a realistic completion date.

Frequently Asked Questions

What does HIU commissioning involve?
HIU commissioning is the process of bringing each Heat Interface Unit into correct working order and proving it. It covers pre-commissioning checks such as system cleanliness and strainer condition, setting the differential pressure control valve, verifying primary flow and return temperatures, confirming domestic hot water setpoint, temperature rise and flow rate at the outlets, checking keep-warm and control settings, commissioning the heat meter and its communications, and recording the results on a per-unit commissioning sheet.
Do you commission HIUs in occupied blocks as well as new builds?
Yes. We commission new-build and retrofit installations before handover, and we also re-commission units in occupied blocks — for example after a network alteration, a plant room upgrade, a heat meter replacement programme or where original commissioning records are missing or units were never balanced correctly.
How many units can you commission or service in a day?
It depends on the unit type, the level of access available and whether the network is fully up to temperature and flushed. Rather than quote a figure that will not hold on site, we confirm a realistic daily rate during the survey and build the programme around it, so the dates in your proposal are dates we can actually hit.
Which commissioning standard do you work to?
We commission to the manufacturer procedure for the unit installed and to your project commissioning specification. Where that specification references heat network guidance such as CIBSE CP1 or the BESA UK HIU Test Regime, we work to the requirements set out in it and record the results in the format your commissioning manager or M&E consultant needs.
Can you take over an annual servicing contract from another contractor?
Yes. We regularly pick up blocks from an outgoing contractor. We start with an asset check to confirm unit brands, models and locations against your schedule, flag any units in poor condition or missing from the records, and then run the block on a programmed annual cycle from that point.
Do you coordinate resident access?
Yes. We book appointments directly with residents, issue reminders, manage rescheduling at no extra charge and report no-access units back to you so they can be chased or re-attended. This is usually the single biggest factor in completion rates on an occupied block.
Which HIU brands do you cover?
All major brands found in London blocks, including Danfoss, SAV, Caleffi, Switch2, Alfa Laval, Heatweb, Thermal Integration and Redan. Mixed-brand estates are handled under one contract, so you do not need a separate contractor per unit type.

Got a Block That Needs Commissioning or Servicing?

Send us the unit count and the HIU brand and we will come back with a proposal, a programme and a completion date you can put in front of your client.

Request a Proposal 020 3951 5133