Commercial & Plant Room Expansion Vessel Servicing
Servicing, pressure testing and replacement of commercial heating expansion vessels in plant rooms, boiler houses and rooftop plant across London. Single large vessels and multi-vessel banks, planned maintenance contracts and out-of-hours attendance to avoid disrupting the building.
What this service covers
Commercial expansion vessel servicing
Commercial vessels carry far higher static heads than domestic systems, so the pre-charge has to be calculated from the plant room’s position in the building, not guessed. We service vessel banks on LTHW heating circuits, chilled water systems and calorifier installations, recording each vessel’s pre-charge, shell condition and valve operation against its asset tag.
- LTHW heating, chilled water and calorifier vessels
- Pre-charge calculated from building static head
- Vessel bank servicing with per-asset records
- Isolation valves and drain points exercised
Plant room expansion vessel servicing & replacement
Plant room expansion vessel work is planned around the building. We attend out of hours where the system cannot be taken offline in the day, isolate vessel by vessel so the circuit keeps running, and replace failed units with matched-capacity vessels. Rigging and access for large vessels in basement plant rooms is arranged as part of the quote.
- Out-of-hours and weekend attendance
- Vessel-by-vessel isolation to keep plant running
- Access, rigging and disposal included in the quote
- Matched-capacity replacements on failure
Large expansion vessel servicing
Large expansion vessel servicing on 200-1000 litre units follows the same principles as domestic work but with proper drain-down management, nitrogen charging and a documented hold test. We also check the pressurisation unit, make-up tank and its pump set, since a failing pressurisation unit is often mistaken for a failed vessel.
- 200-1000 litre vessel servicing
- Nitrogen charging with documented hold test
- Pressurisation unit and make-up tank checks
- Pump set and low-pressure alarm verification
Commercial maintenance contracts
Expansion vessel maintenance contracts fold vessel servicing into your wider plant PPM so nothing is missed at renewal. You get scheduled visits, an asset register with pre-charge history for every vessel, priority breakdown response and a single annual price across all your sites.
- Scheduled annual or bi-annual PPM visits
- Asset register with per-vessel pre-charge history
- Priority breakdown response for contract sites
- Single annual price across multiple properties
Related expansion vessel services
Pressure, heating and control faults often overlap — these pages cover the rest of the system.
Expansion Vessel Servicing, Inspection & Testing
Annual expansion vessel servicing for heating systems, boilers, unvented cylinders and plant rooms across London and inside the M2…
Expansion Vessel Recharge & Repressurisation
Expansion vessel recharging service for heating, boiler and potable systems across London. We drain the water side, reset the air-…
Expansion Vessel Replacement & Repair
Replacement and repair of failed, waterlogged and leaking expansion vessels on heating systems, boilers and unvented cylinders acr…
Potable & Hot Water Expansion Vessel Servicing
Servicing, recharge and replacement of potable (WRAS-approved) expansion vessels on unvented hot water cylinders across London — i…
Also see our underfloor heating repair London and heating pump repair pages.
Plant room vessel service or replacement?
Tell us what the pressure gauge is doing and we will send an engineer with the right vessel and charging kit.
Call 07427 826446Frequently Asked Questions
Engineer labour from £120 + VAT per hour, with a 1-hour minimum. Parts and materials are quoted separately before work begins.
What's included in Commercial Expansion Vessel Servicing
- Condition inspection of each listed asset
- Cleaning tasks agreed for the equipment type
- Functional checks of controls and safety devices
- Readings recorded against the previous visit
- Written findings, with any repairs quoted separately
How Commercial Expansion Vessel Servicing works
- 1
Agree the asset list
Tell us which units are included and how they are used.
- 2
Set the interval
Visit frequency is based on manufacturer guidance and operating conditions.
- 3
Planned visit
The engineer inspects, cleans and tests each listed asset.
- 4
Findings
Readings and defects are recorded; repairs are quoted separately.
- 5
Follow-up
Agreed remedial work is booked, and the next visit is scheduled.
Commercial Expansion Vessel Servicing prices
| Item | Price |
|---|---|
| Engineer labour | £120 + VAT per hour |
| Minimum charge | One hour |
| Parts and materials | Written quote before work starts |
| Planned maintenance contract | Quoted per asset list |
See all rates on our prices page or read why customers choose us.
Commercial Expansion Vessel Servicing: scope, checks and next steps
An expansion vessel accommodates changes in water volume. Rising pressure while heating and discharge from a relief valve can have several causes; they do not prove the vessel needs replacement.
Separate the possible causes
Pre-charge measurement requires the water-side pressure to be relieved correctly. Compare the specified charge, vessel condition, valve leakage and available expansion capacity; measuring against a pressurised water side can mislead.
Repair or replacement?
A vessel that holds its charge may need adjustment rather than replacement. A failed diaphragm, corroded shell or inadequate capacity requires a different scope. Do not adjust a safety valve to mask pressure rise.
Maintenance is not a breakdown repair
A planned visit should establish condition and identify deterioration. An existing fault may need separate diagnosis and parts. Agree which assets, cleaning tasks, functional checks and records are included, and base the interval on manufacturer guidance and operating conditions.
Details to include with your job request
Provide the vessel label, system type, cold and hot pressure readings and where any discharge appears. Do not isolate safety devices or attempt a pressure test yourself.