O&M manual for plumbing and heating: the handover pack

An O&M manual, in full an operation and maintenance manual, is the document a plumbing and heating installer hands over when the job is finished. It tells the people who will live with the system what was installed, how it works, where everything is, how to look after it and who to call. Main contractors ask for one at practical completion. Homeowners rarely ask for one, and are the people who need it most, usually at two in the morning with water coming through a ceiling.

This guide sets out what a domestic plumbing and heating O&M manual should contain, section by section, with the wording we use and the photographs each section needs. There is a free template and a complete sample manual at the end.

What an O&M manual is, and who asks for one

On a commercial or new-build contract, the O&M manual is a contractual deliverable: the main contractor cannot close out the job without it, and the client's facilities team will use it for years. The mechanical section covers the heating, hot water and plumbing installation and is often produced by the subcontractor who installed it.

On a domestic job, a boiler swap, a system refit, a new bathroom, nobody writes one into the contract. It is still worth producing, for three reasons. It stops the phone calls about the stopcock and the thermostat. It keeps the warranties alive, because the manufacturer's servicing conditions are written down where the customer will find them. And it is the clearest evidence, if anything is disputed later, of what was installed and in what condition it was left.

An O&M manual is not the same as the health and safety file required under the CDM Regulations on notifiable projects, though on a large job the mechanical O&M is often appended to it. It is also not a certificate: the gas safety record, the Benchmark checklist and the unvented cylinder certificate are produced separately and go in the manual as attachments.

The structure

A domestic plumbing and heating manual that an occupier can actually use has a fixed shape. Keep it the same on every job so nothing is forgotten.

Part	What it contains
Cover	Operation and Maintenance Manual, the property, the client, the practical completion date, your details
Contents	Every section and every attached certificate, with page numbers
1. Scope of works	What was installed, removed and left in place
2. System description	How the system fits together
3. Heating and hot water controls	What each control does and how to set it
4. Isolation valves and locations	Where every valve is and what it isolates
5. Bathroom and cloakroom	Each room's fittings, valves and care
6. Maintenance	Servicing intervals, what keeps the warranty valid, what the occupier does
Useful contacts	A table of numbers
Certificates and manuals	Attached in order and listed on the contents page

The cover and contents page

The cover carries your logo, the words Operation and Maintenance Manual, the property address, the client's name and the date of practical completion. The contents page lists every section and every attached document with the page it starts on. On a thirty-page manual with six attachments the contents page is the difference between a document and a pile of paper, and it is the part most hand-made manuals leave out because numbering pages by hand after merging PDFs is tedious.

1. Scope of works

A short plain statement of what the job was. What was installed (make and model of boiler, cylinder, controls, radiators, sanitaryware), what was removed, what was left in place and not part of the works, and any limitations: existing pipework retained, a radiator the customer asked to keep. Two paragraphs are usually enough. The point is to fix the boundary of what you are handing over.

The works comprised removal of the existing open-vented boiler and hot water cylinder and installation of a new system boiler, an unvented hot water cylinder in the airing cupboard, a two-zone heating control system, and replacement of the two bathrooms. Existing radiators and pipework on the ground floor were retained and flushed.

2. System description

How the system works, for a reader who has never thought about it. Boiler type and where it is, how heating and hot water are produced and zoned, the cylinder and how it is fed, the pump, the expansion vessel, the filter, the condensate route, the pressure the system runs at and where to read it. Photographs of the boiler, the cylinder and the pipework around them, with the main components labelled, do more than any diagram.

Write for the occupier, and for the next engineer. "The system is sealed and should sit at between 1 and 1.5 bar when cold; the gauge is on the underside of the boiler" is the sentence that stops the first call-out.

3. Heating and hot water controls

Each control gets its own entry: what it is, where it is, what it does and how to use it day to day. Programmer or smart thermostat, room thermostats, zone valves, cylinder thermostat, thermostatic radiator valves, frost protection. Include the settings you left it on. If the controls are app-based, say which app, which account it was set up under, and how to hand the account to the owner.

A photograph of the programmer's screen and of each thermostat, with the room named, belongs here. The manufacturer's instructions go in the attachments; this section is the two-minute version an occupier will actually read.

4. Isolation valves and locations

The most used section of any manual, and the one most often written badly. Every valve the occupier or the next engineer might need, with a photograph and a location they can follow:

• the mains water stopcock, inside and the external one if known;
• the gas emergency control valve at the meter;
• the boiler service valves;
• cold feed and hot outlet isolation to the cylinder, and the cylinder's tundish and discharge route;
• zone valves and the isolation either side of the pump and filter;
• local isolation under every basin, sink, WC and behind each bath and shower panel;
• outside taps and any appliance valves.

Word each entry as a route, not a label: "under the kitchen sink, at the back on the left, blue quarter-turn lever" rather than "kitchen". There is a whole guide to writing the isolation valves section, with the wording and photographs for each kind of valve.

5. Bathroom and cloakroom

One entry per room: the fittings installed with makes and models, the shower or bath valve and how to set its temperature, the location of that room's isolation valves, the extract fan and how it is controlled, and care instructions for the finishes: what to clean sealant and brassware with, what not to use, where the access panel is. Photographs of the valves behind the panel, taken before it was closed, are the single most useful thing in this section.

6. Maintenance

What needs doing, how often, by whom. Annual boiler service by a Gas Safe registered engineer, and that the manufacturer's warranty depends on it. Annual inspection of the unvented cylinder by a competent person, with the safety valves tested. Inhibitor level checked at each service and the filter cleaned. The occupier's own jobs: checking the pressure gauge, bleeding radiators, keeping the condensate pipe from freezing, clearing extract fan grilles, running a shower that is rarely used. Include the dates the first services fall due.

The boiler carries a ten-year manufacturer's warranty. To keep it valid, have it serviced every twelve months by a Gas Safe registered engineer, have the inhibitor level checked at each service, and record each service in the Benchmark checklist at the back of this manual.

Useful contacts

A table, not a paragraph: your office and out-of-hours number, the boiler manufacturer's technical and warranty lines, the cylinder manufacturer, the controls manufacturer, the National Gas Emergency number, the water supplier, the electrician if the wiring was done by someone else. The occupier will photograph this page and stick it inside a cupboard door, so it has to be legible on its own.

Certificates and manufacturers' manuals

The attachments are what the main contractor checks first and what the homeowner will need when the house is sold. For a typical domestic heating and bathroom job:

• the gas safety record for the installation;
• the Benchmark commissioning checklist, completed and signed, which the manufacturer's warranty depends on;
• the unvented hot water cylinder installation and commissioning record, where a G3 cylinder was fitted;
• the Building Regulations compliance certificate that follows from notifying the installation (in England and Wales, through Gas Safe Register for gas work);
• warranty registration confirmations;
• electrical certification for any wiring to the boiler and controls, where it was carried out;
• the manufacturers' installation and user manuals for the boiler, cylinder, controls and showers.

Attach them in that order, give each a divider page, and list each on the contents page with its page number. A photograph of a paper certificate is acceptable if it is legible; a PDF from the certificate app is better. Which certificates belong to whom, and what the installer keeps, is covered in certificates in a handover pack.

Handing it over

Give the client the PDF, and walk them through the controls and the stopcock in person if you can; five minutes at the kitchen table saves an hour on the phone. On a contract job, send the manual to the main contractor with the practical completion paperwork and keep a copy against your own job record. Date it, and reissue it with a new date if anything changes.

A finished sample and a template

The structure is easier to see than to describe. Our sample O&M manual is a manual for a fictional flat refit, a system boiler, an unvented cylinder and two bathrooms, with every section above, a contacts table and the certificates merged in behind a numbered contents page. If you are writing by hand, the free O&M manual template in Word and PDF has the sections with prompts, a contacts table and a certificates checklist.

Frequently asked questions

Is an O&M manual a legal requirement for a boiler installation?

No. The legal requirements are the gas safety and Building Regulations obligations, met by the certificates and notifications. The manual is good practice, a contractual requirement on most commercial and new-build jobs, and the thing that keeps warranties and servicing on track in a home.

What is the difference between an O&M manual and a handover pack?

In the trade the two words mean the same document. "Handover pack" is the term customers and main contractors tend to use; "O&M manual" is what the contract calls it. Both are the sections above with the certificates attached.

Does the manual have to include the manufacturers' instructions?

It should. The user manual for the boiler, the cylinder and the controls belong in the attachments so that the occupier has one place to look. Your own sections give the short version; the manufacturers' manuals give the detail.

Who writes the O&M manual on a job with several trades?

Each trade writes its own section and the main contractor assembles them. On a plumbing and heating subcontract, you are responsible for the mechanical section: the structure in this guide. Send it as a single PDF with its own contents page so it can be dropped into the wider manual.

How long does a domestic O&M manual take to write?

Done after the job from memory and a folder of photographs, an evening. Done section by section as the job finishes, while the valve locations are still in your head, well under an hour, most of which is photographs. Writing it on site is the only reliable way to get the isolation valves section right.

What to do next

On the next job, photograph every valve before the panels go on and fill in the sections above before you leave. Docutrades is O&M manual software that does this on a phone: the fixed sections with photographs, a contacts table, the certificates uploaded and merged in, and a numbered contents page produced for you. The free trial includes five documents and needs no card.