Advice and Troubleshooting

Expansion Tanks

Expansion Tanks are an essential feature on any hot water system. They need to be installed on the hot water supply after the hot water heater. Anywhere on the hot side of the system, but preferably as near to the hot water heater as is reasonably possible. It can be fitted in any orientation.

The tanks are pre set at our factory for most systems, however the pressure is worth checking as some installations are set up with different pump pressures. In general the required pressure setting for an expansion bottle is 5psi above your pump pressure. If you do not know your pump pressure then set the expansion tank to 30 psi.

Surejust accumulator and expansion tanks are supplied complete with mounting bracket and plumbing fitting, ready to connect into your system.

Expansion/Accumulator Tank Size Chart 

 Calorifier Size Recommended Expansion Tank Size
 0-22 Litres 2 Litres
 22-55 Litres 5 Litres
 55-80 Litres 8 Litres
 80-120 Litres 12 Litres
 120-200 Litres 24 Litres
 Expansion/Accumultor Tank Size Physical Size of Expansion / Accumulator Tank
 Width Height Depth
 2 Litres 120mm 300mm 150mm
 5 Litres 180mm 380mm 190mm
 8 Litres 220mm 410mm 230mm
 12 Litres 270mm 400mm 280mm
 24 Litres 260mm 600mm 280mm

Connections to the tank

The engine coil is ready for 15mm I.D heater hose. Fit 2 x jubilee clips on each heater hose to secure to the barbed fittings.

The hot out, cold in and PRV are made for plastic plumbing Hep 2 or speed fit. Use a straight connector or elbow to snap on to the brass fitting. Hot out must be at 12 o’clock (ie at the highest point) and cold in at 6 o’clock (the lowest point).



 What Pressure is the P.R.V (Pressure Release Valve) set at?

Normally the P.R.V will be factory set at 3 or 4 bar, this can be checked by looking at the pressure rating indicator on the face of the red knob.

 Do the dimensions of the cylinders include all fittings and insulation?

Yes, insulation and all fittings suppled as standard with our calorifiers are included within the dimensions stated.

 Is an accumulator tank necessary?

An accumulator tank is usually necessary, we would advise the installation of an accumulator tank as it will help look after the pressure pump and provides a small volume of water to use before your pump kicks in.

 How long does water take to heat up to a usable temperature?

Lots of factors will determine the actual heat up time of the water in your calorifier, however as a rule of thumb a 1 KW immersion will take 30 minutes to heat up 10 liters of water to a usable temperature. When using the engine or diesel heaters the entire tank will generally heat up in approximatley 30 minutes.

 Can an expansion bottle be fitted upside down and where should it be fitted?

An expansion bottle can be fitted in any orientation, the bottle should be installed after the mixer valve.

 The immersion heater isn’t working!

Make sure the manual safety reset button hasn’t popped out. If so identify why this has happened and then reset.

 How do you adjust the output water temeperature?

This can be altered by turning the thermostatic mixing valve to a comfortable temperature fully closed (clockwise is 30 °C or fully open (anticlockwise) 65 °C.

 Do I need a twin or single coil calorifier?

If you only have one heat source (i.e. one or two engines) then a single coil should be used. If you have more than one heat source (i.e. an engine and a diesel heater) then you would use a twin coil.

 My P.R.V keeps dripping or releasing water?

You need an expansion tank fitted or, if you already have an expansion tank, the tank pressure needs altering. When altering the pressure in an expansion or accumulator tank, first switch your pump off and open your taps (cold taps for an accumulator, hot for an expansion tank).