How to use a bypass valve — External Bypass Valve instructions

How to use a bypass valve. Save your resin for the final rinse.

To use a bypass valve on a spot free rinse tank, click the valve into the tank, run bypass mode (plain tap water) for the main wash, then switch to DI mode for the final rinse. You only spend purified water on the rinse that matters — the simplest way to make resin last longer. Here's the setup for the External Bypass Valve.

⏱ ~2 minutes 🔧 No tools needed 🇦🇺 Aussie support
External Bypass Valve clicked into a Spot Free Rinse deionised water tank
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Check before you buy or install This valve is for tanks with the standard black DI head. If your tank already has the Tank Head With Bypass fitted, you don't need this valve — the bypass is built in. Colours vary with stock: you may receive a blue or an orange/grey valve. They work identically.
Setup

Connecting the valve

Click it in, connect your hoses, and you're ready.

1

Click the valve into the tank

Either end works

2

Connect your hoses

Tap in, rinse out

  • Connect the hose from your tap to the valve.
  • Connect your outgoing hose (to your nozzle or pressure washer) on the other side.
  • Turn the tap on and check the connections for leaks.
3

Switch between modes

Bypass or DI

  • Bypass mode: water flows straight through without touching the resin — use this for the main wash with your detergent.
  • DI mode: water flows through the tank and comes out purified — switch over for the final rinse.
Important After switching from bypass to DI, flush out the tap water sitting in your hose before you start the final rinse — otherwise you'll be rinsing with unpurified water for the first few seconds.
Good to know

Tips for longer resin life

The whole point of the valve is to make your resin last — here's how to get the most from it.

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Helpful tips

Best practice

  • Use DI water only when you need it — tap water for the wash, purified water for the final rinse.
  • Leave the valve in bypass between washes so water stays in the tank and air stays out. Air exposure slowly degrades resin.
  • Check your output with the TDS meter now and then — 0 ppm means fresh resin; above 10 ppm means it's time to replace the resin.
FAQ

Bypass valve questions

The questions we hear most about DI tank bypass setups.

When should I use bypass mode?

For everything except the final rinse. Do the main wash — detergent, scrubbing, first rinse — in bypass mode with plain tap water, then switch to DI mode for the last rinse so the surface dries spot-free. Between washes, leave the valve in bypass so water stays sealed in the tank and air stays out.

Does bypass mode extend resin life?

Dramatically. Resin is only consumed while water flows through it, and the final rinse is a small fraction of the water a full wash uses. Running only that final rinse through the tank makes the resin last many times longer than putting the whole wash through it — which is exactly what an external bypass valve makes easy.

Do I need this valve if my tank has the bypass head?

No. The Tank Head With Bypass has the same switching built into the tank head itself, so an external valve would be doubling up. The External Bypass Valve is for tanks with the standard black DI head.

Your bypass valve is ready to go. Questions about your setup? Call or message us — we're happy to help.