Alde Rubber Seal for Expansion Tank Cap – Caravan Heating Seal

Alde Rubber Seal for Expansion Tank Cap – Caravan Heating Seal

The Alde Rubber Seal for Expansion Tank Cap is a small but essential spare part for caravan and motorhome hydronic heating systems. It fits inside the expansion tank cap (often Alde part no. 3000-416 / 1040305) and provides a reliable rubber sealing ring to maintain a watertight, pressure-tight seal on the expansion tank. This helps prevent moisture leakage and pressure loss in the heating loop, ensuring efficient circulation and system performance.

Designed for use with Alde expansion tanks in hydronic central heating circuits, this seal is ideal to replace a worn, hardened or damaged sealing ring whenever the expansion tank cap is opened or serviced.

Why Choose This Expansion Tank Seal?

• 🔧 Essential OEM Replacement – Genuine Alde rubber seal designed specifically for expansion tank caps.

• 🔒 Maintains Tight Seal – Prevents leaks and pressure loss in the hydronic heating expansion tank.

• 💪 Durable EPDM Rubber – Withstands heat, pressure and vibration common in caravan heating circuits.

• 🛠 Low-Cost, High-Value Spare – Inexpensive part that protects your heating system performance.

• 🔄 Simple to Replace – Fits inside the expansion tank cap; replace whenever cap is removed.

Key Features & Specifications

What’s Included

• 1 × Alde rubber seal for expansion tank cap – replacement sealing ring for expansion tank cap assemblies.

How It Works

1. Remove the expansion tank cap on your Alde hydronic heating system.

2. Inspect the old seal for cracks, hardening or deformation.

3. Fit the new rubber seal into the groove of the expansion tank cap.

4. Replace the cap and tighten the fresh seal helps maintain a watertight, pressure-tight connection.

Replacing this seal can prevent leakage around the expansion tank and improve the system’s reliability, especially after cap removal for servicing or refilling.

Who It’s For

• Caravan and motorhome owners with Alde hydronic heating systems

• Technicians performing heating system servicing

• Anyone replacing a worn or leaking expansion tank seal

Why Buy This Replacement Seal?

Even though it’s a tiny part, the expansion tank cap seal plays an important role in maintaining the integrity of your Alde central heating circuit. A worn or hardened seal can lead to leaks, air ingress, and reduced heating performance — small issues that can quickly become bigger problems if left unaddressed. This genuine Alde seal ensures you retain a reliable, long-lasting seal every time the expansion tank cap is opened or replaced.