TMV testing and servicing requirements
The short answer
Thermostatic mixing valves delivering warm water in aged care, hospitals, schools, childcare and disability accommodation must be tested and serviced every 12 months under AS 4032.3, with a major service every 5 years. There is no regulator to lodge with, so the record you keep is the compliance.
Why the record matters more here than anywhere else
There is no authority to submit a TMV test to. That sounds easier, but it means the test record is the entire evidence trail. Facility managers, aged care operators and health departments ask for it at accreditation and audit time, and if the record is not there the test may as well not have happened. One report per valve, and sites often have dozens.
The temperatures you are working to
The mixed warm water at the outlet should sit between 40.5 and 43.5°C after about five minutes of stabilised flow, and it must not exceed 45°C. AS/NZS 3500.4 sets the maximum delivery temperatures that sit behind this: 50°C at sanitary fixtures generally, and 45°C in early childhood centres, schools, and nursing homes and aged care.
The fail-safe test is the important one
Anyone can measure an outlet temperature. The test that matters is the thermal shut-off. Isolate the cold supply and the valve must shut off or drop to a trickle, and it should do it within about 4 seconds, with the outlet not exceeding 46°C while it happens. Then restore the cold and confirm the valve recovers and delivers stable warm water back in range. That is the test that proves the valve will not scald someone when the cold supply drops.
Annual test versus major service
The 12 month visit is a test and service: strainers cleaned, non-return valves checked, temperatures verified, valve tagged. The 5 year major service replaces the thermostat or cartridge and the o-rings and seals, and in practice many just replace the cartridge or the whole valve. Worth tracking both dates separately, because they fall due independently.
Who is responsible for what
The facility owner or operator is responsible for having its TMVs tested and maintained. The work must be done by a plumber holding the TMV endorsement. The servicing plumber keeps the AS 4032.3 test record and the facility keeps a copy, because those are what auditors ask to see.
What the report should record
- Site or facility name and address, and the facility manager contact
- Valve ID or asset number and its location, room by room
- Valve make, model, serial number and size in mm
- Date installed where known, and the date of last service
- Hot and cold inlet temperatures in °C
- Mixed outlet temperature in °C after stabilised flow, and after any adjustment
- Outlet flow rate in L/min against the valve's rated minimum
- Thermal shut-off result, reaction time in seconds, and maximum temperature reached during shut-off
- Test instrument ID and its calibration date
- Service work performed, technician name, licence number and TMV endorsement
What commonly goes wrong
- Outlet temperature in range but the thermal shut-off never actually tested
- Valves with no ID tag, so the record cannot be tied to a specific valve on a site with dozens
- Temperature locking device adjusted or missing, which allows unauthorised changes
- Strainers blocked, which drops flow below the valve's rated minimum and makes it unstable
- The 5 year major service quietly never happening because only the annual date was tracked
Do the check on your phone, hand over the report before you leave
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Common questions
How often do TMVs need to be tested?
Every 12 months for the full test and service, with a major service every 5 years to replace the thermostat, o-rings and seals.
What temperature should a TMV deliver?
Between 40.5 and 43.5°C at the outlet after stabilised flow, and never above 45°C. AS/NZS 3500.4 caps delivery at 45°C in early childhood centres, schools, nursing homes and aged care.
Do TMV test results have to be lodged anywhere?
No. There is no regulator lodgement. The AS 4032.3 record is kept by the servicing plumber and the facility, and produced at audit.
Who can service a TMV?
A plumber holding the TMV endorsement. The test instrument also needs a current calibration date recorded.
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Last reviewed: September 2026. General information for tradespeople, not legal advice. Standards and regulations change. Governing references for this page: AS 4032.3:2022; AS/NZS 3500.4; NSW Health warm water approval specification for health facilities. Confirm the current position with the facility's own accreditation body or state health department before you rely on it.