Commercial Water Heater Repair | Suffolk, Essex & Cambs

Q: How do I book or get a quote?

Call 0800 0996 007, WhatsApp 07947 578332, or email estimates@fastcommercialboiler.help with the site address, the fuel and what you need. Photos of the data plate and any fault code help. Rates can be negotiated.

What we work on

Direct gas-fired commercial storage water heaters
Indirect calorifiers heated from the boiler plant
Plate heat exchangers and gas water heat exchangers
Secondary hot water circulation pumps, blending and thermostatic controls
Leaking vessels, coils and heat exchangers

Typical faults

Burner lockout or ignition failure, thermostat or control faults, scaled heat exchangers in hard-water areas (common across East Anglia), failed secondary return pumps giving lukewarm water at the far end of the building, and leaking tanks or coils. Stored hot water should be kept at 60°C and distributed at 50°C or above for Legionella control, so we check temperatures as part of the repair.

Water heaters are central for hotels, pubs & restaurants, care homes and schools. For wider plant-room faults see plant room repair.

Why hot water plant is separate from space heating

Space-heating boilers warm radiators and air handlers; hot water plant — storage heaters, calorifiers and plate heat exchangers — serves kitchens, showers and washrooms. A building can have heating but no usable hot water, or the reverse. That is why we treat water heater faults on their own page. An annual commercial boiler service can cover both the boilers and the hot water plant on the same visit, so records stay together.

Types of commercial water heater we repair

Direct gas-fired storage water heaters: a burner heats a stored volume of water, typically from around 150 to several hundred litres. Common in hotels, sports centres, schools and kitchens, and often installed in pairs or banks so one can be repaired while the other keeps the building supplied.
Continuous-flow (instantaneous) gas water heaters: wall-hung units, often several linked together, that heat water only when an outlet is open. Faults are usually flow sensors, ignition, fans or scale in the heat exchanger.
Indirect calorifiers: storage vessels heated by a coil from the boiler plant. If the boiler side is working but the hot water is not, the cause is often the primary pump, a motorised valve, the cylinder thermostat or a scaled coil.
Plate heat exchangers: compact units that heat water on demand from boiler water. They are efficient but sensitive to hard water, so descaling or replacing the plate pack is a regular job.
Vented and unvented systems: older buildings often have a vented cylinder fed from a cold water storage tank; newer installations are usually unvented and run at mains pressure, with extra safety devices that need checking.

We also work on oil-fired water heaters (OFTEC trained engineers) and LPG units. Common commercial makes include Andrews, Lochinvar, A.O. Smith, Rinnai and Hamworthy; see our commercial boiler brands page, or send us a photo of the data plate.

What the symptom usually tells us

No hot water anywhere: burner lockout, ignition or flame-sensing failure, a tripped overheat stat, a gas supply problem, or on a calorifier no heat arriving from the boiler.
Hot near the plant room, cool at distant outlets: secondary return pump, non-return valve or circulation balance.
Runs out at peak times: reduced output from scale or a burner fault, or a heater that is now too small for the building.
Rumbling, banging or crackling: scale building up on the base of the vessel or in the heat exchanger, very common with hard water across Suffolk, Essex and Cambridgeshire.
Water at the tundish or a relief valve: an expansion or overheating problem on an unvented system, which should be looked at the same day.
Rusty or discoloured hot water: often a worn sacrificial anode or internal corrosion of the vessel.
Water too hot at the taps: a faulty thermostat or a failed thermostatic mixing valve, which is a scald risk in care homes and schools.

If you smell gas, turn off the gas supply at the emergency control valve if it is safe to do so, open doors and windows, and call the National Gas Emergency Service on 0800 111 999 before calling us.

How a water heater repair visit works

Phone triage. When you call 0800 0996 007 we ask what is happening, the make and model, any fault code and whether part of the building still has hot water. That helps the engineer bring the likely parts.
Safety checks first. The engineer checks the gas supply, the flue and ventilation, and the safety devices before running the heater.
Diagnosis. Burner and ignition checks, combustion analysis on gas units, thermostat and control tests, pump and valve checks, and stored and return water temperatures.
Repair or make safe. Most faults are fixed on the first visit where the part is available. If a part has to be ordered, we tell you how long it will take and whether a second heater or temporary measure can keep the site going.
Written record. You receive a note of what was found, what was done, the temperatures recorded and anything that needs planning, such as descaling or replacement.

Engineers come from our team of over 10 local engineers, based at CO10 8NN near Sudbury and covering commercial sites across Suffolk, Essex and Cambridgeshire.

Safety and compliance for commercial hot water

Gas safety: under the Gas Safety (Installation and Use) Regulations 1998, gas water heaters and their flues must be kept in a safe condition and worked on only by Gas Safe registered engineers. All our gas work is carried out under registration 985448, which you can check on the Gas Safe Register website.
Legionella control: HSE guidance (ACoP L8 and HSG274 Part 2) expects stored hot water to be kept at 60°C or above and hot water outlets to reach at least 50°C within one minute (55°C in healthcare premises). A heater that cannot hold temperature puts that at risk, so we record temperatures on every visit for your water safety records.
Unvented systems: unvented hot water storage over 15 litres comes under Part G3 of the Building Regulations and relies on a temperature and pressure relief valve, an expansion relief valve and an expansion vessel. These should be checked when the heater is serviced.
Scald protection: where vulnerable people use the water, such as care home residents and young children, thermostatic mixing valves are normally fitted at outlets. They need regular testing so the stored water can stay hot while the water at the tap stays safe.

Repair or replace?

Most water heater faults are worth repairing: burners, ignition parts, thermostats, pumps, valves and anodes are all replaceable. Replacement starts to make sense when the storage vessel itself is leaking, when the heater is old and parts are hard to get, or when the building's hot water demand has grown beyond what the heater can supply. In those cases we give you a clear, written comparison of repair and replacement costs. For new heaters and larger plant changes, see commercial boiler installation and replacement.

In hard water areas, an annual service with a check of the anode and heat exchanger, and descaling when needed, is the simplest way to avoid breakdowns. Water heaters can be added to a planned maintenance schedule.

Questions we get asked

Can you repair commercial gas water heaters out of hours?

Yes. Call 0800 0996 007 or WhatsApp 07947 578332 at any time, day or night. Tell us the make and model if you can see the data plate, and whether the building has any hot water at all, so we can bring the most likely parts.

Our hot water is only lukewarm at the far end of the building. Why?

The usual causes are a failed or air-locked secondary return pump, a stuck non-return valve, or circulation that was never balanced after alterations to the pipework. Heavy scale on the heat exchanger can also stop the heater recovering quickly enough at busy times. We test the pump, measure the flow and return temperatures and put right whichever is at fault.

Do you service commercial water heaters?

Yes. A water heater can be serviced on the same visit as the annual boiler service or added to a planned maintenance schedule, so the records sit together in one place.

Water is dripping from the tundish under our water heater. Is that serious?

It needs attention promptly. On an unvented system, discharge at the tundish usually means the expansion vessel has lost its charge, the expansion relief valve is letting by, or the temperature and pressure relief valve has opened because the water is overheating. If the water coming out is very hot or steaming, turn the heater off and call us straight away.

Can a leaking water heater tank be repaired?

It depends where the leak is. Fittings, valves, gaskets and pipe joints can normally be repaired. A leak from the body of a glass-lined storage vessel usually means the vessel has corroded through and the heater needs replacing, and we will tell you that honestly rather than attempt a repair that will not last.

Why does our hot water run out at busy times?

Either the heater is not reaching full output, for example because of scale, a burner fault or a failed thermostat, or it is too small for the demand the building now has. We check the heater first. If it is working as designed but cannot keep up, we can size a larger unit or an extra heater as part of a replacement.

Do you work on oil-fired and LPG water heaters?

Yes. Gas and LPG water heaters are worked on under our Gas Safe registration, number 985448, and oil-fired plant by our OFTEC trained engineers.

Do you repair hot water cylinders in homes?

No. Fast Commercial Boiler Help is commercial only: hotels, care homes, schools, offices, factories, churches and other business premises.

How do I book or get a quote?

Call 0800 0996 007, WhatsApp 07947 578332, or email [email protected] with the site address, the fuel and what you need. Photos of the data plate and any fault code help. Rates can be negotiated.

Commercial hot water plant repair: calorifiers & plate heat exchangers