Jobe Topaz Differential Float Valve – Water Tank Float Valve for Pump-Filled Storage Tanks

Ships directly from the manufacturer.

The Jobe Topaz Differential Float Valve is a high-flow water tank float valve made for storage tanks filled by a pressure-system-controlled pump. Instead of opening a little every time the level drops, it holds shut across an adjustable level difference from 2" up to 8.2 ft (50mm–2.5m) — so your pump starts and stops far less often.

Here's how it works: as the tank empties, a weighted float travels down its cord until it hits the bottom stop, and the valve opens immediately to full flow. The valve stays open while the tank fills and the float rises to the upper stop, which lifts the arm and shuts the valve down. You set both the start and stop levels.

The Differential mounts at the top of the tank — it fits easily through a thin-walled tank or screws into a threaded tank inlet — and Jobe rates it for all makes and models of tanks. It's available in 1/2", 3/4", 1" and 1-1/4" inlets, all supplied with a Detach long tail, backnut and seal washer.

Jobe's patented Detach Valve Seal Access System gives quick access to the valve seal, and the valve is built from glass-filled nylon with 304 stainless steel hardware for water storage tanks, cisterns and irrigation systems.

Features

Adjustable Level Differential
Set start and stop levels anywhere from 2" to 8.2 ft (50mm–2.5m).

Keeps Pump Operation to a Minimum
Fewer pump starts and stops on pressure-switch controlled systems.

Opens to Full Flow
When the float reaches the bottom stop, the valve opens immediately to full flow.

Top-of-Tank Mounting
Fits through a thin-walled tank or screws into a threaded tank inlet.

Detach Valve Seal Access
Jobe's patented Detach system gives quick access to the valve seal.

Which Size Is Right for You?

1/2" Long Tail
3-15/16" thread length, with backnut and seal washer.

3/4" Long Tail
1-13/16" thread length, with backnut and seal washer.

1" Long Tail
2-7/16" thread length, with backnut and seal washer. More flow than the 3/4" at the same pressure.

1-1/4" Long Tail
2-21/32" thread length, with backnut and seal washer. The largest inlet, with more flow than the 3/4" at the same pressure.

Specifications

Inlet Sizes: 1/2", 3/4", 1", 1-1/4" (Detach long tail)
Long Tail Thread Length: 1/2" – 3-15/16" | 3/4" – 1-13/16" | 1" – 2-7/16" | 1-1/4" – 2-21/32" (backnut & seal washer included)
Operating Pressure: 15–150 psi (1–10 bar)
Max Temperature: 140°F (60°C)
Level Differential: Adjustable, 2" to 8.2 ft (50mm–2.5m)
Mounting: Top of tank
Materials: Glass-filled nylon body, EPDM diaphragm, TPU seal, HDPE float, 304 stainless steel hardware

Jobe Topaz Differential Spec Sheet (PDF)

Frequently Asked Questions

What is a differential float valve?
It lets the tank drop a set amount before refilling, then fills all the way back up — instead of topping up constantly. That keeps a pressure-switch pump from starting and stopping over and over.

How should I set my pump's pressure switch?
Jobe recommends watching the pressure your pump runs at while the tank fills, then setting the pressure switch to turn the pump off at least 1 bar (about 15 psi) above that running pressure.

Will it work on a low-pressure gravity system?
The Differential is rated from 15 psi (1 bar) to 150 psi (10 bar) and is designed for pump-filled tanks. For low-pressure troughs, see the Jobe Topaz Float Valve.

Where does it mount?
At the top of the tank — through a thin-walled tank or into a threaded tank inlet.

Fewer pump starts, full refills every cycle — the Jobe Topaz Differential keeps your storage tank and your pump working smarter.