A boiler filling loop connects the mains water supply to a sealed central-heating system so its pressure can be restored when it becomes too low. Traditional filling loops normally use a flexible braided hose and manually operated valves. The Jepp Valve push-button combi boiler filling loop provides a permanent, simple alternative designed to help prevent accidental over-pressurisation and unnecessary water discharge.

What is a boiler filling loop?

A sealed heating system needs sufficient water pressure to circulate correctly. When the pressure drops, the boiler may stop operating or show a low-pressure warning. A filling loop temporarily allows mains water to enter the heating circuit until the correct pressure is restored.

Many conventional boiler filling loops consist of a removable silver braided hose with a valve at each end. Some boilers use an integral key or lever. Whichever arrangement is fitted, filling must be controlled carefully and stopped at the pressure recommended by the boiler manufacturer.

Why does boiler pressure fall?

Pressure can fall after radiators have been bled, following work on the heating system or because of a small water loss. If the pressure repeatedly drops over a short period, simply topping it up is not a cure. A qualified heating engineer should inspect the system for a leak, a problem with the expansion vessel or another fault.

Problems associated with traditional filling loops

• A flexible hose may need to be connected and disconnected correctly.
• Isolation valves can become stiff, seized or difficult to operate.
• A valve left open can continue feeding mains water into the heating system.
• Watching the gauge while filling requires care to avoid excessive pressure.
• An incorrectly managed connection can waste water or cause the pressure-relief valve to discharge.

How the Jepp Valve filling loop works

The Jepp Valve is a permanent push-button filling loop for 15 mm pipework. It combines the filling function with a preset maximum outlet pressure of 1.4 bar. Pressing and holding the button allows water to enter the heating system; releasing it stops the filling operation.

Because the pressure is preset, the Jepp Valve is designed to help prevent the boiler from being over-pressurised during normal topping up. It is suitable for convenient installation where it can be reached by the homeowner, occupier or heating engineer.

How do you use a Jepp Valve?

1. Check the boiler pressure gauge and the pressure recommended by its manufacturer.
2. Press and hold the Jepp Valve button.
3. Watch the gauge as the system refills.
4. Release the button when the required pressure is reached.
5. Check that the pressure remains stable and that there is no sign of leakage.

If the system needs frequent refilling, arrange an inspection by a qualified heating engineer rather than continuing to top it up.

Is the Jepp Valve WRAS approved?

Yes. The domestic Jepp Valve is WRAS Approved under approval number 251215711. WRAS approval confirms that the product has been assessed against the relevant water-supply requirements for its approved use. The Jepp Valve is also patented under patent number GB2527621.

Who is the Jepp Valve suitable for?

The Jepp Valve can be used in homes and managed properties where a sealed heating system requires a filling loop. Its straightforward operation is particularly useful for landlords and housing associations because an occupier can be shown how to restore pressure without handling a loose hose or several isolation valves. Installation should be carried out by a suitably qualified plumber or heating engineer in accordance with the product instructions and applicable regulations.