ATAG Boiler Repairs
& Installation London
Expert ATAG engineers. Same-day emergency repairs, full installations & annual servicing. Gas Safe registered, available 24/7, 365 days a year.
Book This Service
Available 24/7. Gas Safe registered engineers.
2–4 hr Response
Emergency call-out across London
Gas Safe Registered
Every engineer fully certified
ATAG Specialists
Parts stocked on every van
Transparent Pricing
Fixed quotes before work starts
ATAG boiler repairs in London are charged at £150/hr + VAT with no separate call-out fee, and most ATAG faults — pressure faults, circulation issues, error code lockouts or fan failures — are fixed on the first visit by Gas Safe registered engineers who carry ATAG parts on every van. Emergency response is available 24/7 with a 2–4 hour attendance window across Central London.
Quick Facts
- Suitable for
- All ATAG models — One, One Plus, Q Series, X Series, iC Series
- Typical duration
- 1–2 hours for most repairs, same visit
- Cost
- £150/hr + VAT standard, £195/hr out-of-hours, £275/hr bank holidays
- Emergency response
- 2–4 hours across Central London, 24/7
- Parts availability
- ATAG parts stocked on every van
- Warranty
- 12-month parts warranty, 5-year workmanship guarantee
London's trusted ATAG boiler repair & installation specialists
ATAG boilers are among the most premium and efficient heating systems available — and when they go wrong, you need engineers who understand them deeply. At RARE Plumbing & Heating, we have extensive experience servicing, repairing and installing the full ATAG range across London's finest homes. We carry common ATAG parts on every van, enabling same-day fixes in most cases.
ATAG's reputation for near-silent operation and exceptional efficiency makes them the choice for discerning London homeowners in Knightsbridge, Mayfair, Chelsea and Holland Park. However, their sophisticated electronics and high-efficiency heat exchangers require engineers who are genuinely familiar with the brand — not generalists attempting a diagnosis from the manual. Our engineers have worked on ATAG systems for over a decade and understand the nuances of each series.
Common ATAG fault codes — including 78 (water pressure), 103 (circulation fault) and 501 (fan fault) — are misdiagnosed by inexperienced engineers, leading to unnecessary parts replacements and repeat visits. RARE's approach is systematic: we test the root cause before recommending any repair, giving you an honest assessment and a fixed price before work begins.
Our ATAG services
ATAG fault codes explained
Common ATAG error codes and what they indicate:
Outside sensor error
Fault with the outdoor temperature sensor — check wiring and sensor connections
Flow sensor error
Flow temperature sensor fault — check sensor wiring or replace NTC thermistor
Return sensor error
Return temperature sensor fault — sensor may be damaged or wiring disconnected
DHW sensor error
Domestic hot water temperature sensor fault (iC range only) — sensor or wiring issue
Bus communication error
Communication failure between boiler PCB and controller — check wiring and connections
Water pressure out of range
System pressure too low or too high — repressurise to 1–1.5 bar or check for leaks
Circulation fault
Insufficient water flow — airlock, pump failure or blocked heat exchanger
Flow/return temperature differential too high
Temperature difference between flow and return exceeded — check pump and water flow rate
Boiler overheating
Boiler exceeded maximum temperature — pump failure, scale build-up or blocked heat exchanger
Fan fault
Fan not reaching correct speed or not running — faulty fan motor or flue obstruction
If your ATAG is showing an error code, call us immediately rather than repeatedly resetting — some faults need proper diagnosis.
Common ATAG faults we fix
ATAG models we work on
We have specialist knowledge across the full ATAG range.
New ATAG boiler installation
Supply, installation & full commissioning.
ATAG boilers are renowned for their efficiency, quiet operation and build quality — making them the preferred choice for high-specification London homes. We supply and install the full ATAG range, including removal of your old system, magnetic filter fitting, smart thermostat setup, system flush and full warranty registration.
- Removal of old boiler & system flush
- Supply & installation of ATAG boiler
- Magnetic filter installation
- Smart thermostat & controls setup
- Gas Safe certification
- Warranty registration & aftercare
24/7 emergency ATAG repairs
Around-the-clock support, whenever you need us.
An ATAG breakdown is rarely convenient, so we don't make you wait for standard office hours. Our vans are stocked with the parts we replace most often on this range, meaning many faults are resolved in a single visit. Every job comes from a Gas Safe–registered engineer, with pricing agreed before we start — never a surprise on the invoice.
Book an ATAG Engineer
Available 24/7 — Gas Safe registered ATAG specialists across London.
020 7458 4949Book Online"Our ATAG One developed a fault code overnight. RARE had an engineer with us by 8am, diagnosed it immediately and had parts on the van. Back up and running before lunch."
Oliver T. · Knightsbridge
"We specifically chose RARE because of their ATAG expertise. The engineer knew our Q Series inside out — incredibly professional and tidy."
Camilla R. · Mayfair
"Annual servicing and an emergency repair — both handled flawlessly. RARE are the only people I trust with our ATAG system."
Henry B. · Chelsea
Clear rates — no call-out fee, no surprises
We charge a straightforward hourly rate with no separate charge for attending. The clock starts when the engineer arrives — not before. Any parts needed are quoted transparently before work begins, so you'll always know the cost upfront.
No call-out fee · Minimum 1 hour
ATAG repairs — complete topic guide
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System Boiler Installation
For larger homes
Hot Water Cylinder Installation
Megaflo & unvented cylinders
Boiler Installation Costs
Full London pricing guide
Vaillant vs Viessmann
Brand comparison
Boiler Replacement Guide
Repair vs replace explained
Boiler Servicing
Annual Gas Safe service
Boiler Error Codes
140+ codes across 20 brands
ATAG boiler questions answered
Everything you need to know before you call.
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Combi Boiler Installation
New ATAG boiler supply and fit from £3,200.
System Boiler Installation
For larger homes with multiple bathrooms.
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Megaflo & unvented cylinder specialists.
Boiler Installation Costs
Full London pricing guide.
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Brand comparison guide.
Power Flushing
Protect your new ATAG with a system flush.
PPM Membership
Annual ATAG service included in care plans.
Authoritative Sources & References
- SourceATAG Heating Technology UK — Boilers
ATAG Heating UK — The official UK site for ATAG, a premium Dutch boiler manufacturer known for high-efficiency combination and system boilers with industry-leading warranties.
- SourceGas Safe Register — Official UK Gas Engineer Registration Body
Gas Safe Register — The only official gas registration body for gas businesses and engineers in the United Kingdom. By law, all gas engineers must be Gas Safe registered.
- .gov.ukThe Gas Safety (Installation and Use) Regulations 1998
legislation.gov.uk — The statutory instrument that makes it a legal requirement for gas work to be carried out only by competent, Gas Safe registered engineers.
- .gov.ukHSE — Gas Safety (Installation and Use) Regulations 1998: Approved Code of Practice (L56)
Health & Safety Executive — The HSE Approved Code of Practice giving guidance on meeting the requirements of the Gas Safety (Installation and Use) Regulations.
Reviewed by RARE Plumbing London Engineering Team
Gas Safe Registered Heating Engineers · Reviewed 14 September 2026