Sight Gauges – The Low Down

Knowing how much fuel is in your tank is essential for monitoring oil usage, ordering when needed and making sure fuel isn’t lost due to leaks or theft. Atlantis Tanks supplies gauges that quickly and accurately provide this information. One type of gauge we supply, although not commonly used on modern tanks, is the sight gauge.

What is a Sight Gauge?

A sight gauge is a clear plastic tube running up the side of a tank that is open to the atmosphere and shows the level of liquid inside. When the gauge is activated, a valve opens and fuel fills the tube to the same level that’s in the tank. It’s not a float gauge, which sits on the top of the tank and has a float attached via a string that rests on the top of the liquid. Float gauges are also often referred to as clock gauges.

When are Sight Gauges Used?

Sight gauges are a traditional type of gauge and are not often used on modern tanks. However, they still are compatible with single skin tanks and can be used if required. It’s worth remembering that traditional tanks have different sized outlets, whereas modern tanks all have 1″ outlets. This means that sight gauges do not always fit modern tanks, unless some additional parts have been ordered.

REMEMBER: It’s important that sight gauges are used on single skin oil tanks only, or any area protected by a bund. This is quite simply because they are a significant potential leak source. If the plastic tube is bent over, and a push button pressed – if there is one – the oil will flow out.

If the tank is bunded, use one of these gauges instead.

If a sight gauge is required, choosing the right one is vital. You’ll find the information you need to choose the right sight gauge for your tank in the following post:

Type of Sight Gauge

Atlantis supply three different types of sight gauge:

  1. GA.SIGHT.TM4 (& TM6) – TANKMASTER 4 in 1 Sight Gauge Kit
  2. GA.SIGHT4G (& 6G) – Gem Oil Tank Sight Gauge Kit
  3. GA.SIGHT4.1/2 (& 6.1/2) – Sight Gauge Push Button

1 & 2 Tankmaster and Gem Requirements

The TANKMASTER and Gem gauges include a filter and isolation valve as a kit package. Therefore, these two gauge kits don’t require a filter kit supplied as extra. They do, however, need an extension piece depending on the tank they are to be fitted to.

The product code for these extension parts is GA.SIGHT.EXT3 and GA.SIGHT.EXT6. These are 3.5″ & 6.25″ long respectively. All SIS. tanks and SIP. tanks will use the EXT3 extension at all times apart from SIP.H1300 & SIP.H2450 which will use the EXT6 extension. This is because the outlet position is recessed into the tank.

The sight gauges only have a 1/2″ BSP male thread connection whereas the extension piece has a 1″ BSP male thread to fit to the tank and a 1/2″ BSP female thread into which the sight gauge fits.

3 The simple push button gauge

The simple push button gauge is more complicated! If the customer wants this product with a tank we supply, there is a list of parts that must accompany the gauge. The code for this gauge with the parts required is GA.SIGHT4.1/2.ASS & GA.SIGHT6.1/2.ASS (4ft & 6ft respectively).


Our Sight Gauges – Product Details

1 Atkinson Tankmaster Valve

Supplied With:

  • Control Valve to turn on/off oil supply;
  • Pull to Read Valve/Sight Tube allows inspection of tank contents level;
  • Integral Filter to ensure only clean oil is allowed to pass from the tank;
  • Self-Closing Hand Wheel isolates oil supply in case of fire near the tank.


  • PVC Sight Gauge
  • Pull-To-Read valve to isolate flow into tube during rest
  • On/Off Hand wheel
  • Eutectic Solder Fire valve built into hand wheel
  • 10mm Brass Compression Fitting Outlet
  • 52 Micron Nylon Filter (Replaceable)
  • Reversible body for left or right hand exit of compression fitting
  • Stand-off Clip for mounting top of tube to top of tank
  • 1/2″ BSP Male Tank / Extension Fitting

Further Details:

Tankmaster Sight Tubes are supplied with a white UPVC support shield on models up to 5ft and Aluminium support shield on 6ft+ models. Available sizes: 4ft 6″, 5ft, 6ft, 8ft, 9ft, 10ft.


Gem Oil Tank Sight Level Gauge


  • Bottom Outlet Oil Tank Gauge
  • Removable Alloy Bowl Paper Filter
  • 1/2″ M BSP inlet
  • C/w Gauge Level Marking Kit & Calibration Labels
  • Corrosion-resistant Zinc Coated Brass Body
  • Isolation Valve for easy servicing
  • Available in 4’6” size

Further Details:

The Gem Oil Tank Sight Gauge is a traditional, cost effective type of heating oil tank gauge generally used in domestic properties. It is a simple pull to read oil tank level indicator that gives an instant measurement of the tank’s contents, that benefits from an integrated paper filter with alloy bowl for easy removing and cleaning. This oil tank level gauge has an incorporated isolation valve to that it can be serviced or replaced without having the drain the entire tank of fuel.

Designed to fit the bottom outlet of both steel and plastic tanks, and complete with a multi-directional outlet so that it can feed up to two boilers, the Gem fuel tank gauge is suitable for a range of applications.


Push Button Oil Tank Sight Level Gauge


  • Bottom Outlet Oil Tank Gauge
  • 1/2″ M BSP Inlet
  • C/w Gauge Level Marking Kit & Calibration Labels
  • Corrosion-resistant Zinc Coated Brass Body
  • Available in 4′ and 6′ sizes

Further Details:

The Push Button Oil Tank Sight Gauge is a traditional, economical model of heating oil tank gauge, primarily installed on domestic tanks. It works via a simple push to read button, which when pressed, the oil tank level indicator provides the user with an immediate visual indication of the tank’s contents. This oil tank level gauge is constructed of a quality, corrosion resistant zinc plated brass and is suitable for use on both steel and plastic bottom outlet fuel tanks. A user friendly benefit of this fuel tank gauge is that it remains isolated when the button is released.


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