What safety components come with an unvented cylinder?
The inlet control group, expansion vessel, T&P valve and tundish, and what each one does.
Exact kit contents may vary slightly. This depends on the cylinder size and specific application. However, a typical World Heat Cylinders unvented kit generally includes essential unvented cylinder components for G3 Building Regulation compliance. These usually are:
- Cold Water Inlet Control Group: This vital assembly often includes:
- Pressure Reducing Valve (PRV): This valve limits incoming mains water pressure to a safe level for the cylinder.
- Strainer/Filter: It protects downstream components from debris in the water supply.
- Check Valve (Non-Return Valve): This component prevents the backflow of heated water into the cold mains.
- Balanced Cold Water Take-Off (Optional): This can provide a balanced cold water supply to mixers if needed.
- Expansion Vessel: The system requires a correctly sized vessel. It accommodates water expansion during heating, thus preventing over-pressurisation. (Note: For some very large commercial systems, we might supply the expansion vessel separately based on system volume).
- Temperature & Pressure Relief Valve (T&P Valve): This critical safety device discharges water if the cylinder's temperature or pressure exceeds pre-set safety limits.
- Tundish: It provides a visible air gap. This indicates discharge from any safety valve, allowing for early issue detection.
- Motorised Zone Valve (for indirect models): Manufacturers often include this with indirect unvented cylinders. It controls primary heating water flow from the boiler to the cylinder's coil.