Two valves that both "temper" hot water, but aren't interchangeable
The RBM T08 Tempering Valve with Isolation Elbows (Series T08.B) and the RBM T55 Health Series Thermal Flush TMV both sit on the hot water line and deliver a safe, controlled outlet temperature. Past that, they're built for different jobs, and picking the wrong one on a health or aged-care job is a compliance problem, not just an oversized spec.
T08.B: a single-point tempering valve, ready to fit
The T08.B is the RBM T08 High Performance Tempering Valve supplied with isolation elbows already fitted — a thermostatic valve for quick, accurate regulation of hot water outlet temperature at one point of use. It's WaterMark certified, rated to a maximum static pressure of 1,400 kPa and dynamic pressure of 500 kPa, accepts hot water inlet from 55–99°C and cold from 5–25°C, and holds a controlled range of 30–50°C to an accuracy of ±2°C. Minimum flow is 4 L/min, with a maximum inlet pressure ratio of 2:1 between hot and cold supply. It's supplied without insulation and comes in two variants — 20mm valve with 15mm elbows, or 20mm valve with 20mm elbows — so you match the elbow size to the pipework either side rather than the valve body.
T55: built around a thermal disinfection flush, not just tempering
The T55 Health Series does everything the T08.B does — thermostatic control, WaterMark certified, Low-Lead WaterMark licence WMK26384 — and adds a patented, tamperproof, adjustable thermal flush disinfection process, feeding up to 6 outlets from one valve. That flush is the entire point of the product: health and critical-care facilities are required to periodically run hot water lines hot enough to control Legionella growth, then return the outlet to a safe tempered temperature before anyone uses it. A standard tempering valve can't do that cycle; the T55 is built specifically to.
Specs reflect the heavier-duty brief: maximum static pressure 1,600 kPa and dynamic 600 kPa (above the T08.B's 1,400/500 kPa), it'll run on low-pressure systems from just 20 kPa supply, hot inlet up to 90°C, controlled range 35–50°C with a 43°C factory preset, and a minimum 10°C differential between hot and cold inlet temperatures. Minimum flow is the same 4 L/min as the T08.B.
Picking between them
If the job is a single bathroom, a laundry tap or any standard domestic or light commercial point of use, the T08.B is the right tool — it's cheaper, simpler, and does exactly what a tempering valve needs to do. Reach for the T55 only when the install genuinely needs the thermal flush: hospitals, aged care, health and critical-care buildings, or any multi-outlet system (up to 6 points from one valve) where the relevant code requires periodic hot-water disinfection. Specifying a T55 where a T08.B would do adds unnecessary cost; specifying a T08.B where a T55 is required is a compliance gap on a health-sensitive building.
Frequently Asked Questions
What's the actual difference between the T08.B and the T55?
The T08.B is a standard single-point thermostatic tempering valve with isolation elbows fitted. The T55 adds a patented thermal flush disinfection cycle and serves up to 6 outlets from one valve, built for health and critical-care applications where periodic hot-water disinfection is required.
Can I use a T55 instead of a T08.B for a standard bathroom?
You can, but there's no need to — the T08.B is cheaper and does the job. The T55's thermal flush function and 6-outlet capacity are built for health and critical-care compliance, not a typical domestic or light commercial point of use.
What temperature range do these valves control to?
The T08.B holds 30–50°C to ±2°C accuracy. The T55 holds a slightly narrower 35–50°C to the same ±2°C accuracy, with a 43°C factory preset.
Are both valves WaterMark certified?
Yes. The T08.B is WaterMark certified, and the T55 carries a Low-Lead WaterMark licence (WMK26384) specifically.