Makes we repair
Which Netaheat do you have?
A Potterton Netaheat is a wall-hung gas boiler made in three versions: the first Netaheat of 1975, the Mk II F and the Netaheat Electronic. Each version came in two or three sizes. On a Netaheat Electronic, the data badge is in the base of the control cover.
Netaheat 10-16 and 16-22, the first
Made
Its data sheet is dated April 1975
What sets it apart
A pilot lit by a spark, burning while the boiler fires, and a mercury vapour flame safety device
Still made?
No longer made
Netaheat Mk II F 10-16 and 16-22
Made
Last made in 1984
What sets it apart
A printed circuit control panel, a pilot lit by a spark, and a mercury vapour flame safety device
Still made?
No longer made
Netaheat Electronic 6/10, 10/16 and 16/22
Made
Last made between 1983 and 1988, by model
What sets it apart
A spark electronic control, and a data badge in the base of the control cover
Still made?
No longer made
Every Netaheat is room-sealed, with a fan in the flue. Each has a cast iron heat exchanger and a thermostat knob as its one control, and each is made for natural gas. A Netaheat heats the radiators and a hot water cylinder. Its heat exchanger is sized so the hot water can circulate by gravity. No back boiler or floor-standing Netaheat appears in Potterton's papers or in the government's boiler database.
Not a Netaheat? See every Potterton boiler and how each shows a fault, or every make we repair, by type.
The later Potterton Profile, its faults and its reset.
Sources: Potterton's Netaheat papers, each read as a manuals library's copy, and the government's boiler database.
Potterton Netaheat faults, by what you see
A Potterton Netaheat has no fault codes and no warning lights. Its one control is the thermostat knob, and a small window in the front shows whether the burner is lit. A fault shows in what the boiler does, and each panel below starts from that.
The causes come from the Netaheat Electronic's fault-finding chart, the one Netaheat chart found. The 1975 and Mk II manuals describe the same lighting sequence, from the fan to the spark, the pilot and the burner.
The Netaheat gives no heat, and its fan doesn't start
What it means: No power or call for heat is reaching the boiler, or its fan has failed, so nothing starts.
Possible causes, as the Electronic's chart lists them:
- no power from the control to the fan, from the supply, the boiler's fuse or the controls
- the fan's motor
- the control box
What you can do: follow the nearest user advice, the later Netaheat Profile's card. The card says to see that:
- the gas, the electricity and the water are on at the mains
- the time control is in an on period
- no thermostat is set low
Then go through the lighting steps again. The steps are below.
If the boiler still doesn't light, ring us. Leave the case on. The card says a qualified service engineer removes it.
The Netaheat's fan runs, but it never lights
What it means: The fan runs, but the air pressure switch hasn't proved it, so the control won't open the gas. The fan runs for 10 to 15 seconds before the gas comes on, so a short wait is normal.
Possible causes, as the Electronic's chart lists them:
- no power to the switch's circuit at the control
- the air tubes to the switch off or the wrong way round
- the air pressure switch itself
What you can do: the checks in the first panel, and nothing inside the boiler.
If it keeps trying and failing, ring us.
No spark, or the Netaheat's pilot won't light
What it means: The fan is proved, but the spark is missing or the pilot gets no gas, so nothing lights.
Possible causes, as the Electronic's chart lists them:
- no good spark (the electrode or its lead, or the spark jumping somewhere else)
- no gas at the pilot, or a blocked pilot jet
- no power to the gas valve, its leads or its connections
What you can do: see that the gas is on at the meter and your other gas appliances work. The pilot and its electrode sit inside the sealed burner chamber, behind the casing and the chamber's cover, so they're an engineer's job.
If the gas is on and the pilot still won't light, ring us. If you smell gas, don't touch the boiler. Ring the National Gas Emergency Service on 0800 111 999.
The Netaheat's pilot lights, but the spark keeps going or the burner doesn't light
What it means: The flame isn't being sensed, so the spark keeps going, or the main gas valve isn't opening. On the 1975 and Mk II boilers, the burner waits while the pilot heats a mercury-filled phial. That takes about 30 seconds on the 1975 boiler and 40 on the Mk II. The vapour then opens the main gas valve.
Possible causes, as the Electronic's chart lists them:
- the pilot flame not covering the electrode
- a partly blocked pilot jet
- the live and neutral the wrong way round at the boiler's supply
- no power to the main gas valve, its leads or its connections
What you can do: nothing beyond the first panel's checks. A wait before the burner lights is normal, as the last panel shows.
If the burner still hasn't lit after that, ring us.
The Netaheat Electronic cuts out on overheating
What it means: The overheat thermostat has tripped. On a Netaheat Electronic it comes as a kit, fitted where the boiler runs on a sealed system.
Possible causes, as the Electronic's chart lists them: the chart starts with the reset button. If the boiler still has no power after that, the chart points to the overheat thermostat itself.
What you can do: let the boiler cool, then press the reset button once. That's how the nearest user advice, the Netaheat Profile's card, gives it. The card adds that a break in the electricity supply can trip the thermostat too.
The water gets too hot, or the Netaheat won't switch off
What it means: The boiler's thermostat isn't controlling the water's temperature. The thermostat runs from about 55 to about 82 degrees (85 on the 1975 boiler), set at the factory. The manuals say it isn't adjusted on site.
Possible causes, as the Electronic's chart lists them: the thermostat's contacts not switching on and off as the knob turns.
What you can do: turn the knob down. The Netaheat Profile's card warns about a cylinder with no separate control. At a high setting, its stored hot water can reach about 82 degrees and scald.
If it doesn't hold its temperature, ring us.
MoreWhat a working Netaheat shows you
A Potterton Netaheat shows you four things, with no codes or lights, as its manuals describe them. The first three are normal running.
- The burner, through the small window in the frontThe boiler has lit
- A wait before the burner lightsNormal: the fan runs for 10 to 15 seconds first. On the 1975 and Mk II boilers, the pilot then warms a mercury phial for about 30 or 40 seconds. Air in the gas pipe, or turning the knob off and on quickly, can make the wait longer
- It stops in a gas or power cutNormal: it shuts down at once and relights by itself when the supply comes back, the 1975 and Mk II manuals say
- The thermostat knob, from off to MaxOff stops it. The settings run from about 55 to about 82 degrees (85 on the 1975 boiler), set at the factory
The causes are listed in the order of the Electronic's chart, not by how often they happen.
Sources: Potterton's Netaheat manuals (the 1975 data sheet, the Mk II's and the Electronic's) and the later Netaheat Profile's user card, each read as a manuals library's copy, the card a retyped one, on 11 October 2026.
Can you reset or relight a Netaheat yourself?
A Potterton Netaheat has no pilot for you to light, as ignition is automatic. Turning the thermostat knob on starts the fan, a spark lights the pilot, and the pilot lights the burner. On the 1975 boiler, the pilot burns while the boiler fires and goes out when it stops.
The steps, from the nearest user advice. No user guide for these three Netaheats was found. The nearest is the user card for the later Netaheat Profile, a retyped copy, and its steps follow.
To light the boiler:
- Turn the knob to 0.
- Switch the electricity on.
- Set the programmer to an on period.
- Turn the room and cylinder thermostats up.
- Then turn the knob to the setting you want.
After a short wait, the burner shows in the window.
To turn it off: turn the knob to 0, or switch the programmer off. For a long time, switch off the electricity too.
If it doesn't light: see that the gas, the electricity and the water are on at the mains. See too that the time control is on and no thermostat is set low. Then go through the lighting steps once more.
The overheat reset: on a Netaheat Electronic with the kit, let the boiler cool, then press the reset button once.
If the boiler still won't light, or keeps stopping, ring us.
Pressure: no Netaheat paper gives you a pressure step. The 1975 and Mk II boilers were made for open-vented systems. On a sealed Netaheat Electronic, the gauge is on the system, not the boiler. If a gauge reads low, ring us.
Keep the case on. The boiler's safety depends on its casing seal. The manuals say the front cover must seal airtight, and the card says the boiler never runs without its casing fitted and sealed. If the boiler is in a cupboard, keep the cupboard clear and its vents open.
Signs to act on at once: HSE's warning signs of carbon monoxide include these:
- yellow or orange flames
- soot or staining
- a pilot light that often goes out
- more condensation on the windows
If you see any of them, turn the boiler off and ring us. If you smell gas, or a carbon monoxide alarm sounds, ring the National Gas Emergency Service on 0800 111 999. See what to do about a gas smell or a carbon monoxide alarm.
Sources: the later Netaheat Profile's user card, a retyped copy, Potterton's Netaheat manuals, read as a manuals library's copies, and HSE's guidance on carbon monoxide.
Does a Netaheat contain asbestos or mercury?
Asbestos and mercury both appear in Potterton's papers for the earliest Netaheats, each in its own models. No paper says what is in any one boiler today.
- Asbestos: the 1975 data sheet tells the installer to seal the Netaheat 10-16's flue ducts with asbestos rope. Its drawing shows an asbestos rope and an asbestos strip. The Mk II's manual uses glass fibre rope and a ceramic fibre strip in the same places. Whether a 1975 boiler still has its rope takes a survey or a test to show.
- Mercury: the 1975 and Mk II boilers were made with a mercury vapour flame safety device. The device is a phial the pilot heats until the vapour opens the main gas valve. The Electronic's manual, as read, names none.
Leave the flue, its seals and the inside of the case alone. HSE says asbestos was used widely until it was banned in 1999. Disturbing it, HSE adds, releases fibres that cause incurable disease. Anyone who comes across a material they think contains asbestos must stop work. Taking out a 1975 Netaheat 10-16's flue ducts may disturb its rope or strip. Ring us, and we'll ask which Netaheat you have.
Sources: Potterton's Netaheat data sheet and manuals, read as a manuals library's copies, and HSE's pages on asbestos.
Is a Netaheat worth repairing?
A Netaheat can still be worth repairing. Its age alone doesn't settle that. Weigh up three things:
- whether the part it needs can be had
- the repair's rate, set against a new boiler
- how often this boiler has failed
The choice is yours.
Age and parts. The youngest Netaheat was last made in 1988, so any still running is about 38 years old or more. Potterton is part of Baxi, and Baxi says a boiler should last 10 to 15 years with a service every year. In 2020, Potterton said Baxi Genuine Parts supplies parts for all Potterton boilers. Baxi aims to support its products with parts for at least 10 years after it stops making them.
The parts a Netaheat repair can need, by its manuals, include these:
- the electronic control
- the gas valve
- the air pressure switch
- the fan
- the thermostat
Before any repair is agreed, the engineer tells you whether the part yours needs can be had.
Safe to keep using? An older installation that falls short of today's standards isn't necessarily unsafe, Gas Safe Register says. The engineer decides whether yours is safe, on what they find. If it's dangerous, it's turned off with your permission. On a 1975 boiler, asbestos and mercury are set out above. We're an independent firm, not connected with Potterton or Baxi.
The other road is a new boiler. We fit new boilers too. Each is sized with a heat loss calculation, and quoted from photos of the old boiler or after a free survey visit. See what a new boiler includes, and how the day goes. Not sure which road to take? We'll ask what the Netaheat is doing when you ring.
Sources: the government's boiler database, Potterton's page on discontinued boilers, Baxi's Parts Arena and its guide to how long a boiler lasts, Potterton's Netaheat manuals, read as a manuals library's copies, and Gas Safe Register on unsafe situations.
15% off a new boiler, fitted
The 15% comes off the price of a new boiler installation. We quote from photos of your old boiler, or after a free survey visit. Now is the time to replace an old or discontinued boiler.
Terms: 15% off everything in the price we quote for a new boiler installation. That means the boiler, its flue and controls, and the fitting. The offer is for installations booked by 31 December 2026. One offer per home, and not with any other offer.
Do you cover my part of London?
Yes: we travel all over Greater London, day and night, to repair Potterton Netaheats in every borough, north and south of the Thames. We fit new boilers in their place too. Pick your side of the river to see the areas.
North of the river
Every borough north of the Thames: Barnet and Enfield at the top, Hillingdon in the west, Havering in the east, and central London in between.
South of the river
Every borough south of the Thames: Richmond and Kingston in the west, Bexley in the east, and down through Croydon to Sutton and Bromley.
Potterton Netaheat: your questions
Does a Potterton Netaheat have fault codes?
No, a Potterton Netaheat has no fault codes and no warning lights. Its one control is the thermostat knob, and a small window in the front shows whether the burner is lit. Its faults show in what it does, from a fan that won't start to a burner that won't light. Each one, by what you see, is above. If yours has stopped, ring us.
How do I relight a Potterton Netaheat?
A Potterton Netaheat isn't relit by hand, as ignition is automatic. Turning the thermostat knob on starts the fan, a spark lights the pilot and the pilot lights the burner. If the boiler doesn't light, see that the gas, the electricity and the water are on. See too that the time control is on and no thermostat is set low. Then turn the knob to 0 and back up. If the boiler still won't light, ring us.
Does my Netaheat contain asbestos?
Asbestos appears in the papers of one Netaheat, the first 10-16 of 1975. Its data sheet tells the installer to seal the flue ducts with asbestos rope, and shows an asbestos strip. The Mk II's manual uses glass fibre rope and a ceramic fibre strip instead. Whether any one boiler still has its rope takes a survey or a test to show. Leave the flue and its seals alone, and ring us.
Does a Netaheat have mercury in it?
Mercury was part of the first two Netaheats, the 1975 boiler and the Mk II. Each was made with a mercury vapour flame safety device, a phial the pilot heats. The Electronic's manual, as read, names none. Leave the inside of the boiler alone, and ring us if it won't light.
Can a Netaheat run on a sealed system?
A Netaheat Electronic can run on a sealed system when its overheat thermostat kit is fitted, its manual says. The 1975 and Mk II manuals describe open-vented systems, fed from a feed and expansion tank, and don't mention sealed ones. When you ring, we'll ask which Netaheat you have.
Is the Potterton Netaheat still made?
No, Potterton no longer makes the Netaheat. The government's boiler database gives 1984 as the Mk II's last year, and 1983 to 1988 for the Electronic's sizes. It lists no Netaheat as current. We repair Netaheats wherever the part can be had.
Can you still get Netaheat parts?
Whether a Netaheat part can be had depends on the part itself. In 2020, Potterton said Baxi Genuine Parts supplies parts for all Potterton boilers. Baxi aims to support its products for at least 10 years after it stops making them, and the last Netaheat was made in 1988. The engineer says which part has failed and whether it can be had. Before any repair starts, the rate is agreed in writing.
How much does a Netaheat repair cost?
What a Netaheat repair costs depends on the part, the time the job takes and when it's done. Evening, overnight and weekend rates are higher. The rate is agreed in writing, once the engineer has found the fault and before any work starts. See how our rates work.
Do I need to know which Netaheat I have?
You can ring without knowing which Netaheat you have. Say what the boiler is doing, and we'll ask the rest. The model on the boiler helps if you can read it, but finding the fault is the engineer's job.
Don't know what has failed? You don't have to.Ring and say what you can see or hear. Finding the fault is our job.
Calls answered 24 hours a day
A real person answers and gives you the rate on the call. No work starts until you say yes, and repairs are guaranteed for 12 months: parts, labour and any return visit.
