Boiler replacement RAMS

HSE 5-STEP · CDM 2015

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Remove an existing domestic gas combi boiler and install a new wall-hung combi boiler in an occupied house, including draining and refilling the system, flue installation and termination, and the electrical connection, carried out by a Gas Safe registered engineer.

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Removal of an existing domestic gas combi boiler and installation of a new wall-hung gas combi boiler at 8 Beechcroft Close, Sheffield S11 7D**, for Mrs J. Okafor. Works include gas isolation and purge, draining and refilling of the heating and hot water system, flue installation and correct termination, the fused electrical connection, commissioning and a tightness test. All gas work is carried out by a Gas Safe registered engineer in accordance with the Gas Safety (Installation and Use) Regulations 1998 and BS 6798, and the household is occupied throughout.

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Document details
Contractor	Halewood Heating Services Ltd
Author	R. Naylor, Gas Safe Registered Engineer (reg. no. held on card)
Client / Principal Contractor	Mrs J. Okafor
Site	8 Beechcroft Close, 8 Beechcroft Close, Sheffield S11 7D**
Project reference	HHS-3164
Start / duration	Tue 23 Jun 2026 / 1 day

1. Scope of works

2. Sequence of works

Method statement, safe system of work

Operatives arrive, confirm the scope with the householder, explain the expected duration and the periods when gas, water, heating and electricity will be off, and confirm welfare arrangements.
Verify Gas Safe registration is current and appropriate to the appliance category, and confirm the engineer holds the relevant competencies (CCN1, CENWAT).
Protect access routes and the immediate work area with dust sheets; establish a clear, tidy working space around the existing boiler and keep occupants and pets away from it.
Inspect the existing installation, flue route and termination, gas supply and electrical supply; check for any signs of spillage, staining or previous unsafe work before starting.
Isolate the electrical supply to the boiler at the fused spur, lock or cap off, and prove dead with a voltage indicator and proving unit before disconnecting.
Turn off the gas supply at the appliance isolation valve, and where required at the meter, and confirm the appliance is isolated before any disconnection.
Isolate the mains water and turn off the heating and hot water; allow the system to cool to avoid contact with hot water and hot surfaces.
Connect a hose to the drain-off point and drain the heating system and hot water to a safe foul drain, managing the discharge to avoid scalding and slips.
Disconnect the old boiler from the gas, water, condense and electrical connections, cap the open gas connection immediately, and remove the flue.
Remove the old boiler using a two-person lift and safe manual handling, and set it aside for controlled removal from site.
Prepare the wall, mount the new boiler bracket and hang the new boiler securely, checking fixings are suitable for the wall construction.
Install and connect the flue, ensuring correct fall, seals, support and a compliant termination position with the required clearances to windows, doors and boundaries.
Make the gas, water, condensate and heating connections, fit isolation valves, and pressure/soundness check the wet connections.
Reconnect the electrical supply at the fused spur, verify polarity and earth continuity, and confirm correct fusing before energising.
Carry out a gas tightness (soundness) test on the installation pipework to GSIUR requirements, and purge the supply safely; do not proceed if the test fails.
Fill and vent the system, add inhibitor, bring the system up to pressure and check all joints for leaks.
Commission the boiler to the manufacturer's instructions, carry out a flue gas analysis with a calibrated analyser, and record combustion readings.
Check for correct operation, complete the Benchmark commissioning checklist and the Gas Safe notification/Building Regulations compliance, and register the appliance.
Demonstrate the boiler and controls to the householder, hand over manuals and certificates, and advise on the fitted carbon monoxide alarm.
Remove all waste and the old boiler for controlled disposal, clean the area, account for all tools and leave the property secure.

3. Risk assessment

HSE 5-STEP · MHSWR 1999 REG 3 · HIERARCHY OF CONTROL

Risk assessment: hazards, who may be harmed, controls and residual risk
Hazard	Who / how	Existing controls	L×S	Additional controls	Residual
Uncontrolled release of natural gas during disconnection, connection or purging (fire, explosion, asphyxiation).	Operatives, householder, occupants, property. Explosion or fire can cause serious injury or fatality.	Gas Safe registered engineer with current CCN1/CENWAT. Appliance isolation before disconnection. Open ends capped immediately. No ignition sources near gas work.	2×5=10	Isolate the gas supply at the appliance and, where needed, at the meter before any disconnection. Cap open connections immediately. Carry out a full tightness (soundness) test to Gas Safety (Installation and Use) Regulations 1998 requirements and purge safely before commissioning; do not commission if the test fails. Ventilate the area, prohibit smoking and naked flames, and keep a gas leak detector to hand. Report any escape to the National Gas Emergency line (0800 111 999).	Low
Carbon monoxide exposure or flue gas spillage from incorrect flue installation, termination or combustion.	Householder, occupants, operatives. CO poisoning can cause serious injury or fatality.	Gas Safe registered engineer. Manufacturer's flue kit and instructions. Awareness of CO symptoms.	2×5=10	Install the flue to the manufacturer's instructions with correct fall, seals and support, and terminate at the required clearances from windows, doors, openings and boundaries. Carry out a flue gas analysis with a calibrated analyser and record combustion readings within the manufacturer's limits. Complete the Benchmark checklist. Fit or confirm a working audible CO alarm to BS EN 50291 and brief the householder on CO symptoms and what to do. Classify any unsafe situation under the Gas Industry Unsafe Situations Procedure.	Low
Electric shock during isolation, disconnection or reconnection of the boiler electrical supply.	Operatives, occupants. Electric shock can cause serious injury or fatality.	Engineer competent to 18th Edition for the electrical connection. Insulated tools. Awareness of the fused spur supply.	2×4=8	Follow safe isolation: isolate at the fused spur, lock or cap off, prove dead with a voltage indicator and proving unit before touching conductors. Verify polarity, earth continuity and correct fuse rating before re-energising. Do not work on the electrical connection while the gas or water connections are being made live. Use RCD protection where appropriate.	Low
Contact with hot water, hot surfaces or steam when draining and working on the system (scalds and burns).	Operatives, occupants. Scalds and burns.	Allow the system to cool before draining. Controlled draining to a foul drain. Awareness of hot surfaces.	2×3=6	Turn off heating and hot water and allow the system to cool before disconnection. Drain via a hose to a safe foul point, directing discharge away from operatives and occupants. Wear gloves when handling hot components. Keep occupants clear of the discharge route. Manage spillage to prevent slips.	Low
Manual handling of the old and new boilers and materials.	Operatives. Musculoskeletal injuries to back, shoulders and hands.	Two operatives on site for team lifting. Manual handling awareness. Clear access routes.	3×2=6	Assess the weight before lifting; use a two-person lift for the boiler in line with the Manual Handling Operations Regulations 1992. Drain the old boiler as far as practicable before removal to reduce weight. Keep access routes clear, use good lifting technique and avoid twisting. Use a step ladder rather than overreaching when hanging the boiler.	Low
Working in an occupied home: disruption to a vulnerable occupant, trip hazards, dust, and loss of heating/hot water.	Occupants (distress, cold, injury from hazards), operatives (slips, trips), property (damage).	Pre-start discussion with the householder. Dust sheets and tidy working. Consideration of occupant needs.	3×2=6	Agree the plan and off-supply periods with the householder in advance and keep the outage as short as practicable. Protect floors and furnishings with dust sheets, keep escape routes clear, and clean as work progresses. Keep tools and materials away from children and pets. Restore heating and hot water the same day or agree temporary arrangements if a fault is found. Leave the property secure and warm on completion.	Low
Work at height at the external flue termination or when hanging the boiler (falls from a step ladder).	Operatives. Falls can cause fractures or head injury.	Boiler sited at low level internally. Inspected step ladder for internal work. Most flue work reachable from ground or a step ladder.	2×3=6	Use an inspected, suitable step ladder or a secured ladder on firm, level ground for the external flue termination, maintaining three points of contact and not overreaching. Where the termination cannot be reached safely from a ladder, use a tower or other suitable access. Do not work at height in adverse weather. Keep the base of any ladder clear and the area below controlled.	Low

4. Plant & equipment

Gas engineer's hand tools (spanners, adjustables, pipe cutters)
Flue gas analyser (calibrated, in date)
Gas tightness test gauge / manometer
Voltage indicator and proving unit
Cordless drill and bits
Draining hose and pump
Step ladder (EN 131 compliant, inspected)
System flushing and inhibitor equipment
Carbon monoxide alarm (BS EN 50291)

5. Materials / COSHH

System inhibitor, cleanser and, where soldering is used, flux and solder are handled in accordance with their Safety Data Sheets: avoid skin and eye contact, wear nitrile gloves, and ensure ventilation. Any leaded solder is avoided on potable water lines. No soldering is carried out as hot works under this method unless separately assessed and permitted. The old boiler and any packaging are removed for controlled disposal; no asbestos is anticipated but work stops and is reassessed if any suspected asbestos-containing material is disturbed.

6. PPE

Safety footwear (steel toe caps)
Safety glasses/goggles
Work gloves (and heat-resistant gloves for hot components)
Nitrile gloves (when handling inhibitor/flux)
Kneeling protection for low-level work
Dust mask (P2 or higher, when drilling)

7. Competence & training

The engineer is Gas Safe registered with current CCN1 (core gas safety) and CENWAT (central heating and water heaters) competencies appropriate to the appliance, and is competent to 18th Edition IET Wiring Regulations for the electrical connection. R. Naylor (Author) holds current Gas Safe registration and is responsible for commissioning, notification and handover. All operatives hold manual handling awareness training. Gas Safe registration is verified as current before works begin.

8. Permits

Gas isolation controlled by the Gas Safe registered engineer prior to disconnection.
Electrical isolation of the boiler supply (safe isolation at the fused spur) before electrical work.
Building Regulations compliance notified via Gas Safe (competent person self-certification) on completion.

9. Access & egress

Access is via the front door to the room where the boiler is sited, with the route kept clear of tools, hoses and materials at all times. The householder's normal means of escape from the dwelling is maintained throughout. Where the external flue termination is worked on, safe access is arranged from a step ladder, secured ladder or tower on firm ground.

10. Welfare

Toilet and hand-washing facilities are used by arrangement with the householder where offered and suitable; otherwise the nearest agreed facility is used. Operatives carry drinking water and take breaks away from the immediate work area to minimise disruption to the household.

11. First aid

A stocked first aid kit is carried in the company vehicle and its location is known to all operatives. In the event of serious injury, gas escape or suspected carbon monoxide exposure, evacuate affected persons to fresh air and call 999 immediately. Suspected CO exposure is treated as a medical emergency. The site address is available for the emergency services.

12. Emergency procedures

On any smell of gas or suspected gas escape, do not operate electrical switches or ignition sources, isolate the supply at the meter, ventilate the area, evacuate occupants and call the National Gas Emergency line on 0800 111 999. On suspected carbon monoxide exposure (alarm sounding or symptoms), evacuate to fresh air, isolate the appliance and seek medical help via 999. In the event of fire, evacuate, call 999 and do not re-enter. Any dangerous gas situation is classified under the Gas Industry Unsafe Situations Procedure, and reportable incidents are notified under RIDDOR.

13. Environmental

The old boiler and any scrap metal, pipe offcuts and packaging are segregated and removed from site for recycling or controlled disposal. System water drained during the works is discharged to a foul drain in a controlled manner, avoiding surface water drains and watercourses; inhibitor-dosed water is not released to the ground. Noise and dust are minimised in the occupied dwelling. No hazardous waste is anticipated beyond general trade waste.

This document was AI-generated as a drafting aid. It is not a substitute for professional health & safety advice. It must be reviewed, verified and made site-specific by a competent person before use, briefed to all operatives, and updated when site conditions or the method change. The provider accepts no liability for use of this document on site.

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