Regal Twin 3672
Two 36 x 72 inch softening vessels working in alternation on a single 2 inch twin connector, each with its own 570 litre brine tank. One softens while the other regenerates or stands by, so 18.2 m3 per hour of soft water is available without interruption, twenty-four hours a day.
About the Regal Twin 3672
The Regal Twin 3672 is a twin alternating water softener. Two 36 x 72 inch vessels work in turn on a single 2 inch twin connector, each with its own 570 litre brine tank. One vessel softens while the other regenerates or stands by, so the full rated flow stays available through every regeneration.
It gives 18.2 m3 an hour of service flow at a 1 bar pressure drop. The vessels are supplied without media, which is quoted separately to match your water analysis: Ecomix or cation exchange resin.
At a glance
- What it is
- A twin alternating water softener
- Service flow
- 18.2 m3/h at a 1 bar drop
- Vessels
- Two 36 × 72 inch, 1011 L each
- Brine tanks
- Two 570 L, overflow-protected
- Valve
- WS2CE 2.0 inch, metered
- Media
- Ecomix or cation exchange resin, quoted separately
- Dry weight
- 280 kg (2 × 140 kg)
- Model code
- RF3672CE2-TW
What it does.
- 18.2 m3/h of soft water, uninterrupted: alternating twin duty
- Full rated flow stays available through every regeneration
- Metered 2 inch control: regeneration by measured volume
- Two 1011 L vessels with 570 L overflow-protected brine tanks each
- Media-ready for Ecomix or cation exchange resin, quoted to your water analysis
- Expandable: 2 to 6 units on one system controller
Typical applications
Who the Regal Twin 3672 is for
- Sites that cannot lose soft water while a vessel regenerates.
- Operations that need soft water twenty-four hours a day.
- Sites that need high flow: up to 18.2 m3 an hour.
- Sites that need double flow at peak rather than uninterrupted supply: the same two vessels can be built as a duplex set.
- Operators who may add units later: 2 to 6 can run on one system controller.
How the Regal Twin 3672 works
In general, a water softener swaps the calcium and magnesium that cause hard water for sodium, using a bed of ion exchange resin. When the resin is used up, the softener regenerates with salt brine and rinses the hardness away to drain.
In the Regal Twin 3672, the two vessels alternate. While one is in service, the other regenerates or stands by. The metered WS2CE 2 inch valves regenerate by measured volume rather than by a clock, so each vessel is regenerated when it needs it.
The datasheet gives a service flow of 18.2 m3 an hour at a 1 bar drop and a backwash flow of 26.1 m3 an hour at 1.7 bar. Optional extras on the datasheet include a service and fill switch (V3017), a motorised alternating valve (V3076BSPT) and a meter assembly (V3094BSPT).
Which one should you choose?
The Regal range runs from under-sink cabinets to twin alternating vessels. The right one depends on how much soft water you need, and how fast.
Regal 100
You have limited space under the kitchen sink and want a cabinet softener: 10 L of resin, 1.0 to 1.2 m3/h.
Regal 150
You want a little more capacity under the sink: 15 L of resin, 1.3 to 1.5 m3/h and 3 m3 between regenerations.
Regal 200
You want the most capacity in the cabinet range: 20 L of resin, 1.6 to 1.8 m3/h and 5 m3 between regenerations.
Regal 500
You need a floor-standing softener with a separate brine tank and up to 6.12 m3/h of service flow, with the media you choose.
Regal 750
You want a ready-loaded commercial softener: 75 L of resin, 3.5 m3/h continuous and 15 m3 between regenerations.
Commercial Softener RF1465SO1
You want a 14 × 65 inch tank with a CE 1 inch valve and a large 146 L brine tank, with your choice of resin or Ecomix.
Regal Twin 3672
You need soft water that never stops: two 36 × 72 inch vessels working in turn, with 18.2 m3/h of service flow.
Installation and servicing
The Regal Twin 3672 connects with G 2 inch inlet and outlet, a G 1.5 inch drain and G 3/8 inch brine lines. The connection height is 2395 ± 30 mm and the dry weight is 280 kg (2 × 140 kg), before media and water, so we plan the floor loading and the room at survey.
The datasheet lists a 230 V, 50/60 Hz supply (2 × 30 W), an inlet pressure of 2 to 6 bar and a feed temperature of +4 to +30 °C. Media per vessel is Ecomix A/C/P at 600 L or cation resin at 700 to 725 L, quoted separately. 2 to 6 units can run on a WSSYSTCON2 controller, and a duplex arrangement on a DUPLECO2 connector is listed as an alternative.
The survey is chargeable and is credited back if you go ahead.
Regal Twin 3672 questions answered
What flow does the Regal Twin 3672 give?
18.2 m3 an hour at a 1 bar pressure drop. Backwash flow is 26.1 m3 an hour at 1.7 bar.
Will I lose soft water during a regeneration?
No. The vessels alternate, so one softens while the other regenerates or stands by.
How big are the vessels?
Two 36 x 72 inch vessels of 1011 L each, with 570 L brine tanks.
Does it come with media?
No. The media is quoted separately: Ecomix A/C/P at 600 L per vessel, or cation resin at 700 to 725 L per vessel.
How does it regenerate?
By measured volume, using metered WS2CE 2 inch valves.
How heavy is it?
The dry weight is 280 kg (2 × 140 kg), before media and water.
What power does it need?
230 V, 50/60 Hz, 2 × 30 W.
Can I add more units?
Yes. 2 to 6 units can run on a WSSYSTCON2 controller, in progressive flow, alternator, series or random modes.
What connections does it have?
G 2 inch inlet and outlet, G 1.5 inch drain and G 3/8 inch brine.
Is there a smaller version?
For lower flow, the Regal 750 gives 3.5 m3 an hour continuous. The Regal 500 gives up to 6.12 m3 an hour.
Do you supply and install it?
Yes. We supply and install it. The survey is chargeable and is credited back if you go ahead.
Related products
Figures come from the manufacturer datasheet (PDF). Reviewed November 2026.
Supplied, installed and serviced across the UK
Across most of southern and eastern England, mains water is very hard. Rain filtering through chalk and limestone dissolves calcium and magnesium, and that scale coats heating elements, so we size every system to your supply and your equipment.
Tell us about your site and what you need the water for. We specify the system, fit it and keep it running under Comprehensive Maintenance.
Source: Drinking Water Inspectorate, Drinking Water Quality in England triennial report (2020–2022).
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