Waimana Flow-Activated UV Unit - 33W & 48W, 25mm BSP, Whole House UV Treatment NZ

UV treatment for homes that already have pre-filtration in place — or new installs being built alongside a filter system. The Waimana UV unit adds flow-activated ultraviolet treatment to your existing setup, treating water against bacteria, viruses, and microbes without chemicals.

The integrated flow switch is the key feature. The UV lamp only activates when water is moving. When flow stops, the lamp shuts off automatically. No water warming in a lit chamber between uses, no unnecessary power draw, no lamp running idle overnight.

Available in 33W (30 LPM) for smaller homes and baches, and 48W (45 LPM) for medium to large homes with higher flow demand.

UV unit only — no filter housings or cartridges included. For effective UV treatment, pre-filtration must be installed upstream.

Key specs at a glance

	33W	48W
UV lamp	33W	48W
UV dose	30 mJ/cm²	30 mJ/cm²
Max flow rate	30 L/min	45 L/min
Connection	25mm BSP	25mm BSP
Max pressure	116 PSI / 8 bar	116 PSI / 8 bar
Operating temp	2–40°C	2–40°C
Power supply	240V	240V
UV lamp life	Varies with usage
Warranty	3 years

Why choose the Waimana UV unit

• Flow-activated UV — lamp only runs when water is moving, saving power and extending lamp life
• Prevents water warming in the chamber during no-flow periods — no stagnant heated water between uses
• Chemical-free treatment — no dosing, no additives, no ongoing consumable cost beyond the lamp
• Two wattage options — 33W for smaller homes and baches, 48W for larger homes and higher flow demands
• Standard 25mm BSP connection — suits most existing NZ plumbing setups
• Compact and wall-mounted — easy to integrate into an existing filter system
• Everything included — UV lamp, quartz sleeve, ballast, flow switch, spring, and O-rings
• 3-year warranty

How it works

The UV chamber sits downstream of your pre-filtration. Water flows through the chamber where the UV lamp treats it against bacteria, viruses, and microbes. The lamp delivers a UV dose of 30 mJ/cm² — the level recognised for effective microbiological treatment.

The integrated flow switch controls the lamp automatically. When a tap opens and water moves, the lamp activates. When flow stops, it shuts off. This prevents the water in the chamber from warming up during idle periods, which would otherwise create a small volume of warm, potentially stale water at the head of the UV chamber each time a tap opens.

For UV to work effectively, the water entering the chamber must be clear. Pre-filtration is essential — sediment and turbidity block UV light from reaching micro-organisms in the water. If you're pairing this unit with a new filter system, get in touch and we'll help you choose the right pre-filtration configuration to work upstream of this unit.

Choosing between 33W and 48W

33W — suits smaller homes, baches, and holiday homes with lower flow demand. Maximum flow rate of 30 L/min delivers a UV dose of 30 mJ/cm².

48W — suits medium to large homes and higher-demand rural properties. Maximum flow rate of 45 L/min at 30 mJ/cm². The higher wattage lamp delivers the same UV dose at a higher flow rate, making it the right choice where multiple taps or appliances may be drawing water simultaneously.

If you're not sure which suits your household, get in touch and we'll help you choose.

Important — pre-filtration required

UV treatment is only effective when water entering the chamber is clear. This unit does not include filter housings or cartridges. Pre-filtration must be installed upstream before the UV chamber. At minimum, a 1 micron final sediment stage is recommended before the UV unit. For new installs, get in touch and we'll help you select the right pre-filtration configuration to pair with this unit.

Technical specifications

UV lamp	33W or 48W (select from dropdown)
UV dose	30 mJ/cm² at rated flow
Max flow rate	30 L/min (33W) / 45 L/min (48W)
Connection	25mm BSP
Max pressure	116 PSI / 8 bar
Operating temperature	2–40°C
Power supply	240V
Activation	Flow switch (auto-on when water flows, auto-off when flow stops)
UV lamp life	Varies with usage
Warranty	3 years
Includes	UV lamp, quartz sleeve, ballast, flow switch, spring, O-rings
Does not include	Filter housings or cartridges

What's in the box

• Waimana UV chamber (stainless steel)
• UV lamp
• Quartz sleeve
• Ballast with power lead and 3-pin plug
• Flow switch
• Spring
• O-rings

Frequently asked questions

Do I need pre-filtration before this unit?

Yes — UV treatment is only effective when water entering the chamber is clear. Sediment and turbidity block UV light from reaching micro-organisms. Pre-filtration is essential. At minimum, a 1 micron sediment stage upstream is recommended. If you're building a new system, get in touch and we'll help you configure the right pre-filtration to pair with this unit.

What's the difference between 33W and 48W?

Both deliver a UV dose of 30 mJ/cm² — the difference is flow rate. The 33W handles up to 30 L/min; the 48W handles up to 45 L/min. Choose based on your household size and peak water demand. Smaller homes and baches suit the 33W; medium to large homes with higher simultaneous demand suit the 48W.

What does flow-activated mean?

The integrated flow switch detects when water is moving through the system and turns the UV lamp on. When flow stops — all taps off, no demand — the lamp shuts off automatically. This prevents water sitting in a lit, warming chamber between uses, and means the lamp isn't running unnecessarily.

How long does the UV lamp last?

UV lamp life varies with usage — specifically, the volume of water that flows through the system. The more water used daily, the sooner the lamp reaches the end of its effective UV output. UV output degrades before the lamp visibly fails, so don't wait for it to stop glowing. Replace on schedule and clean the quartz sleeve at each lamp change.

What is the quartz sleeve?

The quartz sleeve surrounds the UV lamp inside the chamber, keeping the lamp dry while allowing UV light to pass through to the water. Scale or deposits on the sleeve reduce UV transmission and treatment effectiveness. Clean it at each lamp change and replace if it becomes scratched or cloudy.

Do I need bypass valves?

They're not included but worth adding. Bypass valves let you isolate the UV unit during lamp and sleeve changes without shutting off water to the rest of the house. Ask us about adding a set when you order.

Do I need a plumber to install it?

For most customers, yes — a licensed plumber is the safest path. The unit uses standard 25mm BSP fittings and plugs into a standard 240V outlet. If you're confident with household plumbing, the installation is straightforward. Get in touch if you're unsure.

What warranty does it come with?

3 years, covering the UV chamber and workmanship. The UV lamp is a consumable and is not covered by the product warranty.