Thermostatic Mixing Valve (TMV) Maintenance Checklist
Keep blended water safe from scalding without compromising legionella control — temperature checks, the fail-safe shut-off test, and servicing under TMV2/TMV3 schemes.
What is a tmv maintenance checklist?
A thermostatic mixing valve (tmv) maintenance checklist is a structured list of the 10 preventive maintenance tasks — covering visual, functional, cleaning and record-keeping checks — that keep a thermostatic mixing valve (tmv) running safely and reliably. It groups routine checks by frequency, from daily inspections to annual servicing, so FM teams and building engineers can plan and evidence preventive maintenance.
Core tmv checks
- Inspect the valve, strainers, and check valves for scale or debris
- Measure the blended outlet temperature against the set safe value
- Clean or replace inlet strainers and service the cartridge as scheduled
- Record temperatures, the fail-safe result, and servicing in the log
What is a thermostatic mixing valve (tmv)?
A thermostatic mixing valve blends hot and cold water to deliver a safe, stable temperature at outlets — protecting users from scalding while allowing hot water to be stored and distributed hot enough to control legionella. TMVs are common on showers, baths, and basins in healthcare, care, education, and public buildings. Healthcare TMV3 valves follow NHS guidance (D08), and others follow the TMV2 scheme. Maintenance balances two competing risks: scald protection and legionella, so it focuses on outlet temperatures, the fail-safe cold shut-off test, and periodic servicing and descaling.
This checklist is one of 25 in our plumbing and water system maintenance checklists, covering pressurisation units, booster sets, storage tanks, TMVs and water treatment — pressure, hygiene and legionella control.
Typical TMV maintenance checklist
A practical starting point for planned preventive maintenance. Always refer to the manufacturer's O&M manual and site-specific requirements.
Visual Checks
- Inspect the valve, strainers, and check valves for scale or debris
- Confirm the valve is sited to minimise the dead leg to the outlet
- Check identification and that the valve type suits the application (TMV2/TMV3)
Functional Checks
- Measure the blended outlet temperature against the set safe value
- Carry out the fail-safe test — shut off cold and confirm the valve stops flow
- Check hot and cold supply temperatures feeding the valve are correct
- Verify the outlet temperature stabilises quickly and holds steady
Cleaning & Housekeeping
- Clean or replace inlet strainers and service the cartridge as scheduled
- Descale the valve and outlet where hard-water scaling is present
Record Keeping
- Record temperatures, the fail-safe result, and servicing in the log
Download the free TMV maintenance checklist PDF
Get all 10 tasks as a printable PDF — free, no signup needed. Keep a copy in the plant room, attach it to work orders, or share it with your maintenance contractor.
Typical maintenance frequency
Suggested intervals for thermostatic mixing valve (tmv) maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.
Every 6 Months
- •Outlet temperature check and fail-safe test
- •Clean strainers
- •Inspect for scale (healthcare: more frequent initial checks)
Annually
- •Full service per TMV2/TMV3 scheme
- •Cartridge service or replacement
- •Descale valve and outlet
- •Reverify set temperature
Common faults and issues
Issues to be aware of when maintaining thermostatic mixing valve (tmv) equipment.
Safety and compliance notes
Key safety considerations for thermostatic mixing valve (tmv) maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.
Reference standards and frameworks
- United Kingdom
- HSE ACoP L8 and HSG274 for water hygiene
- North America
- ASHRAE Standard 188 (legionellosis risk management)
Frameworks commonly referenced when planning tmv maintenance programmes. Always confirm the requirements that apply to your site and jurisdiction.
Managing TMV documentation with PM Assist
PM Assist helps FM and building operations teams search their O&M manuals and building drawings in seconds. Upload your thermostatic mixing valve (tmv) documentation and ask questions like “What temperature is each TMV set to?” or “Which outlets are served by TMVs?” — and get source-cited answers instantly.
See PM Assist answer questions about a real tmv manual — try the live demo, no signup needed.
Take this checklist with you
Download the branded PDF, generate a custom version for your asset, or run AI search across all your building documentation.
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Further reading on tmv maintenance
Frequently asked questions
How often should a TMV be serviced?
What is the TMV fail-safe test?
Why do TMVs need careful legionella management?
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