SPECIAL OFFERS
Onyx 50L Red Heating Vessel ONYX50LHEAT
Onyx 50-litre red heating expansion vessel with a 3/4 inch connection and 1.5 bar pre-charge.
At a glance
£67.03
£55.86 ex. VAT · VAT at 20%
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Onyx 50L red heating vessel is an expansion vessel for sealed heating systems. It uses a 1.5 bar pre-charge to absorb the expansion of water as it heats, helping to keep system pressure stable. The vessel has a 3/4 inch connection.
Signs this part needs replacing
- System pressure rises quickly when the heating is on and drops when cold
- Water weeping or discharging from the pressure relief valve
- Visible corrosion, rust or water staining on the vessel body
- Pressure gauge reads low even after topping up the system
- Boiler shows a low pressure fault or locks out
Before you order
- Confirm the connection size is 3/4 inch and matches the existing pipework
- Check the 1.5 bar pre-charge is suitable for the system's design pressure
- Verify there is enough space for a 50 litre vessel
- Check the vessel's mounting arrangement and orientation
No specification data held for this part.
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| SPECIAL OFFERS Pressure Vessels & Accessories | — | — | — |
Documents & drawings
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No documents held for this part. The technical team will source them from the manufacturer — usually the same working day.
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