The Bobil Expansion tank complements the SureCal calorifier hot water system and provides a safer and smother water system. It comes pre-assembled and pressure set for easy installation.  Use 15mm push fit plastic plumbing fittings to install.
 
PLEASE NOTE - THIS IS NOT NEEDED WHEN USING IN CONJUNCTION WITH A BOBIL WATER HEATER. THE SILICONE HOSE IN THE BOBIL KIT ALLOWS FOR EXPANSION.
 
What is an expansion tank and why should I fit one?
 
An expansion tank is a safety device used in closed water heating systems such as a when a calorifier is used on a boat. It will absorb excess water pressure, which can be caused by thermal expansion as water is heated, or by water hammer
 
What size should I fit?
 
The expansion tank should measure 10% of the calorifier capacity. I.e. the 2 litre expansion tank would work with the 10 - 22 litre calorifier.
 
Where should I fit one?
 
It should be fitted after the thermostatic mixer valve on the calorifier but before the first outlet. It comes pre assembled with a connection ready to push straight into a plastic plumbing tee piece.
 
What does it come with?
 
You get the 2L tank, a bracket for mounting, a steel strap, a 15mm to 1/2" compression fitting and a 1/2” bsp to 10mm barbed fitting, four clips and a brass tee piece to attach to the hybrid kit (if you needed to do this).
 
What pressure should it is set to?
 
The expansion tanks come pre pressurised to go with the SureCal calorifier. If you need to change this then it should be set to a pressure above your pump pressure but below the pressure release valve cut out pressure. This is very important or the expansion tank wont work properly.