Altecnic Reflex Heating Expansion Vessel 35 Litre HV35C

The Reflex 35 litre Heating Expansion Vessel is a diaphragm expansion vessel manufactured by Altecnic and part of the Reflex range. It is fitted to sealed heating systems to absorb the increase in water volume as the system heats up, limiting pressure fluctuations and protecting components from sustained over-pressure. The vessel sits on the heating side of the system and works alongside the filling loop, pressure relief valve and system gauge.

• Water discharging from the air valve when the valve is depressed, indicating a split or perforated diaphragm.
• System pressure rising sharply as the boiler heats up, then dropping again as it cools.
• The pressure relief valve discharging during normal operation, with the vessel failing to absorb expansion.
• Frequent topping up of system pressure, or the pressure gauge reading high when cold.
• Audible water sloshing or knocking from the vessel body, suggesting the diaphragm has failed and the vessel has filled with water.

• Confirm a 35 litre vessel matches the system volume and expansion requirements for the installation.
• Check the connection size and thread on the existing vessel against the replacement before committing to the job.
• Verify the available space, mounting arrangement and access to the vessel connection point, particularly on wall-mounted or back-boiler installations.
• Check the system's operating pressure and static head to confirm the vessel is suitable for the application.