Hardware setup

Guardian’s hardware is all off-the-shelf LinkTap and Shelly gear — nothing proprietary, nothing you can’t replace at a hardware store or online. This page covers each device in turn. For models, kits, and purchase links, see Supported Devices; for the first-time end-to-end flow, start with the Quick start.

LinkTap gateway & smart valve

The water system is two parts: the LinkTap Gateway (GW-01/02), a Zigbee-to-Wi-Fi bridge that lives inside your rig or dock box, and the LinkTap G2S smart valve that physically opens and closes the water. Newer G1S/G4S valves also work. Use a model with the built-in flow meter — it’s what enables metering and volume-based shutoffs.

Pairing

1. Power the gateway somewhere dry, within range of both your Wi-Fi and the spigot, and join it to the same network your phone or laptop uses at the rig.
2. Pair the valve to the gateway. Zigbee has good reach, but masonry pedestals and metal hulls eat signal — if the link is flaky, move the gateway closer to the spigot.
3. Add the gateway in Guardian. The app talks to it over its local HTTP API, so valve control works with no internet at all.

Put the valve at the source spigot

Install the valve directly on the campground or marina spigot, then run your hose from the valve to the rig:

1. Source spigot — the campsite or marina water source
2. LinkTap valve — threaded straight onto the spigot
3. Water hose — from the valve to your rig
4. City-water inlet on the boat or RV

Many owners hang regulators, filters, and shutoffs on the inlet at the side of the rig. That leaves the hose itself completely unprotected — and hoses are the part that fails. They sit in the sun, get stepped on, and see every pressure swing. If a hose bursts while you’re away and the valve is downstream of the burst, the valve can’t do anything about it. At the spigot, the valve guards the hose and everything after it, and the heavy hardware hangs on a sturdy metal spigot instead of your rig’s plastic fittings. If you stack on Y-splitters or filters, use a hose stand to take the weight.

Flow metering

The G2S meters water as it passes, which gives Guardian two things: usage tracking (how much water you actually ran) and volume-based limits — every valve open carries a volume/duration limit, so a burst line ends with a bounded amount of water rather than an open tap. How those limits fit into the overall protection model is covered in Water control & safety.

Shelly Flood Gen4 — flood & high water

The Flood Gen4 is a small battery-powered Wi-Fi sensor with exposed probes on its underside. Water bridging the probes fires an alarm immediately.

Battery life and deep sleep — read this before you worry

The sensor spends almost all of its life in deep sleep to stretch its battery. It wakes to push an event the instant its probes get wet, and briefly on periodic wake cycles to report in. Between those moments it is unreachable — by design.

Placement

Water finds the lowest point; so should your sensors. One sensor per trouble spot, probes down, on a surface where the first inch of water will pool:

• Bilge — the essential one on a boat; place it above the normal residual-water line so it signals abnormal water, not the usual dampness.
• Under sinks — galley and head, where supply-line drips start.
• Water heater bay — tank and relief-valve failures show up here first.
• Low points — under the fresh-water pump, near the shower sump, wet bays, any spot where a leak would collect.

At ~$30 each, a second or third sensor is the cheapest protection upgrade you can buy.

Shelly Plus Uni — battery voltage

The Plus Uni is a compact interface module with a 0–30 V voltmeter input, which covers both 12 V and 24 V banks. Wired to your house or starter bank, it gives Guardian continuous voltage readings — the earliest warning you get that a charger has failed or something is quietly draining the bank that runs your bilge pump.

Wiring

• Wire the Uni to the battery through fused leads — an inline fused ring-terminal harness is cheap and protects the circuit if anything chafes. See the battery kit for the recommended harness and enclosure.
• In damp or exposed locations (engine bays, battery boxes), mount it inside a small waterproof junction box.

Configuration in the app

• Enable the voltmeter: the Uni’s voltmeter input is a peripheral that must be switched on — Guardian can enable it for you from the app, so you don’t need to dig through Shelly’s own interface.
• Calibration offset: long wire runs and connector drops can skew readings by a tenth of a volt or two, which matters when state-of-charge lives in a narrow band. Compare against a multimeter at the terminals and set the offset so the app matches reality.
• Chemistry presets: pick your bank’s chemistry — Flooded, AGM, Gel, or LiFePO₄ — at 12 V or 24 V. Each chemistry maps voltage to charge differently (a “full” LiFePO₄ and a “full” flooded bank sit at very different voltages), so the preset is what makes the readings meaningful.

Shelly PM Mini Gen3 — shore power

The PM Mini Gen3 is a compact AC power meter. Wired into your shore-power feed, it does two jobs:

• Shore-power loss detection: the moment the pedestal drops out — tripped dock breaker, campground outage, someone unplugging the wrong cord — Guardian knows, instead of you finding out from a warm fridge two days later.
• AC consumption: it tracks how much power you’re drawing, useful for spotting loads you forgot were on and for slips or sites with metered power.

Once wired and on the network, add it in Guardian and it appears under your vehicle’s Power system alongside the battery monitor.

Buying hardware

All models, current price estimates, ready-made kits (water, battery), and purchase links live on the Supported Devices page. Prices vary by region, but a typical full build — water valve and gateway, a flood sensor, battery monitoring, and shore-power metering — runs about $265–290, one-time. No hardware subscription, ever.