Ideal Logic Combi 30 Expansion Vessel 175551 Replacement Part

This ideal logic combi 30 expansion vessel absorbs heating-system expansion to keep boiler pressure stable. Over time, the diaphragm can fail or the charge can drop, so pressure rises when heating and then falls when cool, and the PRV may start discharging outside. Common symptoms include frequent re-pressurising, pressure swings, and low-pressure lockouts. Replacing the correct vessel restores proper pressure control and helps prevent repeat shutdowns.

Compatibility :

• I Mini: 24, 30
• +C: 24, 30, 35
• Independent: C24, C30, C35
• Code Combi ES: 26, 33, 38
• Combi E: 24, 30, 35
• Combi ES: 24, 30, 35
• Combi ESP: 24, 30, 35
• Logic + Combi: 24, 30, 35
• Logic Code Combi: 26, 33, 38
• Logic Combi: 24, 30, 35
• Ultra Combi: 30, 35

Important fitting advice

We recommend that all parts are fitted by a fully qualified Gas Safe registered engineer. If you need help confirming the right part, contact us our team has 10+ years of boiler spares knowledge and friendly chat support to help you quickly.

Delivery

At Boiler Spares Hub, we dispatch orders within 1 working day (Monday-Friday). Orders placed outside working days will be dispatched on the next working day. For delivery options available for this product, please add it to your basket or check our delivery options page.

Returns

We accept 30-day returns. Returns must be in an unopened, sealed box. If we find the item has been used or installation was attempted, we may refuse the return.

Frequently Asked Questions (FAQs)

1. What does the expansion vessel do on an Ideal Logic Combi 30?
It cushions pressure changes as water heats up, so the boiler stays within safe pressure limits.

2. How do I know if my Ideal expansion vessel has failed?
Fast pressure rise when heating, pressure dropping when cold, PRV discharge pipe dripping, and repeated topping up.

3. Can a bad expansion vessel cause the boiler to lose pressure?
Yes, because it can force the PRV to release water, and the system pressure then keeps falling.

4. Is 175551 correct for Ideal Logic Combi 30?
Yes, manufacturer code 175551 covers Ideal Logic Combi 30 and several related Ideal combi ranges.

5. Should a Gas Safe engineer fit this part?
Yes, use a qualified engineer for safe installation and correct repressurising/commissioning.