St AlbansMon–Sat 8:00–17:30 · 24/7 Emergency · Gas Safe Registered info@heatrite.uk07455 74863507702 52346407584 076105 About Domestic Commercial Service Areas Our WorkContact07455 748635 Request Estimate Warm Air · Ducted Heating · Gas Safe # Warm Air Heater Service, Repair & Replacement Genuine specialist cover for ducted warm air systems, Johnson & Starley, Powrmatic, Benson and Reznor, with full service, repair, ductwork checks and like-for-like or modernised replacement when the unit is past it. Book warm air engineer 07455 74863507702 523464 J&S · Powrmatic · Benson · Reznor · Gas Safe specialist - Johnson & Starley trained - Commercial & domestic warm air - Ductwork inspection included - Honest repair-vs-replace advice - Genuine OEM parts where available Service overview ## What warm air heater service, repair & install actually involves. Plain-English breakdown, so you know exactly what you're paying for, and why it matters before we set foot on site. ### What it is Service, repair, fault diagnosis and replacement of gas-fired warm air heaters, domestic ducted units (Johnson & Starley Hi-Spec, Aquair, WarmCair) and commercial direct/indirect fired heaters (Powrmatic, Benson, Reznor, Ambirad), including ductwork and grille checks. ### Who it's for Owners of 1960s–1990s homes with original ducted warm air heating, light industrial and warehouse occupiers, churches and village halls with overhead warm air units, and facilities managers maintaining commercial heater banks. ### When you need it Annual service overdue, recurring lockouts, loss of flame, sooting or carbon monoxide concerns, weak airflow at grilles, noisy fans, slow warm-up, or a quote for like-for-like replacement when the unit is past economic repair. ### Why it matters Warm air heating is increasingly a specialist field, most domestic engineers haven't worked on a J&S Hi-Spec and most commercial gas engineers don't routinely touch ducted units. A specialist visit catches sooting, cracked heat exchangers and dangerous combustion drift early, and an honest repair-vs-replace conversation saves owners from sinking money into a unit at end of life. The cost of doing nothing ## What goes wrong when this is ignored. Warm air units fail in ways that domestic boiler engineers don't always recognise, and the consequences can be quietly serious before they become obvious. ### Risks of waiting - Cracked heat exchangers leak combustion gases into the airstream, the only system in your home that's designed to blow that air at you. - Sooting at the burner is a sign of incomplete combustion and a CO red flag, easily missed without a proper combustion analysis. - Failed flame supervision devices can let unburnt gas accumulate in the burner chamber, then ignite. - Blocked or collapsed ductwork chokes airflow and overheats the heat exchanger from the inside. ### Common mistakes - Letting a domestic boiler engineer 'have a look' at a J&S Hi-Spec, the fault patterns and parts catalogue are different worlds. - Skipping annual servicing because 'it still warms up', warm air units degrade silently between failures. - Patching up a unit at 30+ years old when a modern replacement would pay back in 4–5 winters. - Forgetting the ductwork, dirty filters, blocked grilles and disconnected runs make any warm air install perform poorly. Our process ## How the job actually runs. Same system every time. No improvising on your floor. - 01 ### On-site diagnosis We listen to symptoms, check fault history if available, inspect the unit, ductwork, return air path, grilles and any flue components. - 02 ### Combustion analysis Calibrated flue gas analyser reading at the burner, gas pressure check at the inlet, flame supervision test, heat exchanger inspection where accessible. - 03 ### Repair or replace recommendation If the fault is repairable on an economically viable unit, fixed-price repair quote. If the unit is end-of-life, an honest replace quote with options. - 04 ### Carry out the work Parts sourced from OEM or specialist refurb stockists. Replacements with like-for-like J&S Aquair / WarmCair, or upgrade to a modern condensing wet-system alternative. - 05 ### Commission & paperwork Combustion readings recorded, ductwork airflow tested at representative grilles, service report or commissioning certificate issued. What you get ## The outcomes that matter. ### Genuine warm air specialism Most engineers don't work on ducted units regularly, we do. Trained on Johnson & Starley, Powrmatic and the commercial direct/indirect fired range. ### Honest repair-vs-replace advice If a 30-year-old unit is at end of life, we'll say so. If the fault is a £180 fix on a unit with another decade in it, we'll do the fix. ### Ductwork looked at, not ignored Filters, grilles, return paths and run condition all checked, the part most engineers skip. ### Safety-first combustion checks Combustion analysis on every service, flame supervision tested, heat exchanger inspected. CO risk taken seriously. ### Genuine parts where possible OEM J&S, Powrmatic and Reznor parts via authorised stockists, refurb/specialist sources where OEM is discontinued. ### Domestic and commercial Same engineer covers a J&S Hi-Spec in a Hertfordshire family home and a Powrmatic bank in a warehouse. In depth ## Everything worth knowing before you book. The details a salesperson skips. Skim it, or read every word, both are useful. Questions on this? Talk to a Gas Safe engineer direct. 07455 748635 07702 523464 ### Why warm air is increasingly specialist Ducted warm air heating was common in UK homes built in the 1960s–1980s, then largely displaced by wet radiator systems. Many of those original units (Johnson & Starley Hi-Spec, Aquair and the later WarmCair range) are still running, but the engineers who know them are retiring. We've kept the specialism alive because warm air, when properly maintained, is a fast, responsive and surprisingly efficient way to heat a home. ### Common Johnson & Starley faults Failed fan motors, sticking gas valves on early Hi-Spec units, cracked heat exchangers (the unit-ending fault), failed flame supervision devices, blocked condensate drains on the modern WarmCair condensing range, and air filter neglect choking the return air path. Most are repairable on a unit under 20 years old, the heat exchanger crack is usually the end of the line. ### Commercial direct-fired vs indirect-fired Direct-fired commercial warm air heaters (Powrmatic NV/NVx, Benson) inject combustion products directly into the heated airstream, suitable only for well-ventilated industrial spaces with no occupancy proximity concerns. Indirect-fired units (Reznor, Powrmatic CPx) use a sealed heat exchanger and a separate flue, suitable for occupied workshops, warehouses and retail. We work on both, with the correct testing procedures for each. ### Repair vs replace, the honest call A Johnson & Starley unit from the 1990s with a healthy heat exchanger and a £180 fan fault is worth fixing. The same unit with a cracked heat exchanger isn't, the part alone (where still available) is £600–£900 plus a day's labour, on a 25+ year old chassis. A modern J&S WarmCair condensing replacement, or a conversion to a wet radiator system with a high-efficiency boiler, usually pays back inside 5 winters on gas savings alone. ### Ductwork is half the system Even a perfectly serviced unit can't push warm air through choked ductwork. We pull and clean return air filters (often unchanged for years), check the duct runs for collapsed insulation and disconnected joints, and verify airflow at representative grilles. On older installs, a duct clean and rebalance often delivers more felt improvement than the heater service itself. General work gallery ## Recent Heatrite jobs that show the standard of our work. A broader look at recent installs, hot water systems, testing work and finished jobs across domestic and commercial sites. Commercial heating Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Oil heating Installed and commissioned by Heatrite. Unvented cylinders Installed and commissioned by Heatrite. Hot water systems Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Gas testing Installed and commissioned by Heatrite. Bathroom installation Installed and commissioned by Heatrite. Unvented cylinders Installed and commissioned by Heatrite. Bathroom installation Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Hot water systems Installed and commissioned by Heatrite. Hot water systems Installed and commissioned by Heatrite. Oil heating Installed and commissioned by Heatrite. Unvented cylinders Installed and commissioned by Heatrite. Boiler installation Installed and commissioned by Heatrite. Unvented cylinders Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Hot water systems Installed and commissioned by Heatrite. Commercial heating Installed and commissioned by Heatrite. Previous slideNext slide Frequently asked ## Straight answers, no fluff. Can't see your question? Call 07455 748635 or 07702 523464. Do you service Johnson & Starley warm air units?Yes, J&S Hi-Spec, Aquair, WarmCair and modern condensing WarmCair are core specialisms. Servicing, repair and like-for-like replacements. Can you fix a unit that's locking out? My heat exchanger is cracked, can it be repaired? Should I replace warm air with radiators? Do you do commercial Powrmatic / Benson / Reznor? Do you check the ductwork too? Payment & finance ## Card, Klarna or Clearpay, pay the way that suits you. Boilers, bathrooms and larger installs can be spread over time with Klarna or Clearpay finance, just ask when you book. - ### Card payments on site We carry a card machine in the van, tap, chip & PIN or contactless on completion. ### Klarna Spread the cost of your boiler or bathroom install with flexible Klarna finance options. ### Clearpay Pay over time with Clearpay, ideal for boilers, cylinders and full bathroom fits. Ready when you are ## Book your warm air heater job today. Written fixed quote. Gas Safe engineer. No upsell, no pressure. Book warm air engineer 07455 748635 07702 523464 Gas Safe registered 24/7 cover 5-star rated locally Related services ## Other things we look after. ← Back to homepage ### Boilers Learn more ### Power Flushing Learn more ### Bathroom Installations Learn more ### Plumbing Learn more Gas Safe heating & plumbing specialists based in London Colney, St Albans, serving homes and commercial properties across Hertfordshire & the Home Counties. Mon–Sat 8:00–17:30, with 24/7 emergency response. ### Domestic Boiler Installation & Servicing - Plumbing - Emergency Call Outs - Bathrooms - Vented & Unvented Hot Water Systems - Heating & Hot Water Controls - LPG Heating & Boilers ### Commercial - Plant Room Installation & Purging - Tightness Testing & Purging - Power Flushing - Commercial Plumbing - Commercial Heating & Gas - 24/7 Call Out - Unvented Hot Water Systems - Warm Air Heaters - Maintenance Contracts ### Company - About - Service Areas - Our Work - Reviews - Contact ### Contact - 07455 748635 - 07702 523464 - 07584 076105 - info@heatrite.uk - 17 Manor Rd, London ColneySt Albans AL2 1PN © 2026 Heatrite Plumbing & Heating Ltd. All rights reserved. Privacy PolicyCookie PolicyTerms & Conditions·Company No. 15149175 · Gas Safe Call nowRequest Estimate