The Netaheat Profile, subsequently re-named Potterton Profile
The Netaheat Profile is different from all the preceding Netaheats. So
different that I don't really regard it as a Netaheat at all, but it
bears the name so I'll include it here! The Netaheat Profile was
short-lived model. Not because there was anything wrong with it, quite
the opposite, it is an excellent boiler! It was
shortlived because they changed its name to plain 'Potterton
Profile'.. The 'Netaheat' part of the name being
dropped and the boiler went on to sell in tens of thousands as the Potterton Profile. The Netaheat Profile is a complete redesign of
the Netaheat from the chassis up. The case is different, the heat
exchanger is different, as are the gas valve, control board and burner
assembly. A further important difference was the addition of an
overheat protection thermostat which makes this boiler suitable for
installation is sealed system format, unlike all previous Netaheats. The
Profile was never the runaway success that the Netaheat was however,
mainly because by now all Potterton's competitors had learned from the
Netaheat and developed similar and equally good boilers and the Netaheat
Profile was no longer the only candidate in the marketplace for high
efficiency wall mounted gas boilers.
Here are the common problems with the Netaheat Profile:
1) Thermostat failure.
The boiler overheat thermostat trips, requiring the user to press the
hard-to-find button back in. (It's deep in a hole in the underside of
the boiler in case you need to find yours...) When tripped, the boiler
simply appears dead. Nothing happens whatsoever. There can be three
reasons for it tripping: Failed primary thermostat leading to the boiler
genuinely overheating, failed overheat protection thermostat producing
false trippings, boiler heat exchanger overheating locally due to
accumulation of corrosion deposits. The easiest way to diagnose this is
to replace both thermostats together as a first step. If doesn't fix it,
I suggest replacing the boiler. The heat exchanger cannot be effectively
cleansed in my experience. Powerflushing has minimal effect so a new
heat exchanger would seem a good solution, but the heat exchanger is
not, and has never been, available as a spare part.
1) Flue Fan Failure
As with all Netaheats, and all fanned flue boilers of any make in
fact, failure of the fan is a common fault. Combustion air is drawn by
the fan through the combustion chamber so it is a
safety-critical component. If the fan fails to start, the safety device
which tests to see if the fan is running before allowing the pilot to
light will detect the failure and stop the boiler from lighting. To the
user the boiler will stay silent (or possibly hum quietly) instead of
bursting into life as normal when a demand for heat is turned on. The
fan on the Profile is freely available as a spare part and is fairly
straightforward to install.
2) Air Pressure Switch failure
The safety device which tests the fan for correct operation is the
air pressure switch. These are know to fail occasionally and the result
is the fan runs, the boiler sounds for all the world as though it is
about to light, but no ignition ever occurs.
3) Control board failure.
Having so many functions, the control board can fail in a variety of
different ways. The burners may randomly light and go out, or simply
refuse to light. The Pilot may light but the boiler fails to progress to
main burner ignition, sometimes with the pilot ignition spark continuing
indefinitely. The boiler may also seem to start it's ignition sequence
correctly by running the fan, but then shut down and start over again
repeatedly and rarely progress to lighting the pilot.
4) Gas Valve failure
The 'combined function gas valve' turns the gas on and off to the
pilot light and to the main burner in response to electrical signals
from the other controls, and it regulates the gas pressure to the main
burner. When they fail the pilot or the main burner fails to light. There
were several different gas valves fitted to the various sizes of Profile
and all were pretty reliable. The White-Rogers gas valve fitted to most
is no longer available.
6) Pilot light failing to light or being very small.
Easily fixed and associated with lack of proper servicing. A problem
common to many boilers. The pilot jet has become blocked or partly
obstructed with debris and needs poking out with some fusewire. Part of
the manufacturer's service procedure!
The Potterton Netaheat Profile is the first and last of of the
Netaheat range to feature an overheat protection thermostat as standard.
This is to allow it to be connected to a sealed heating system as well
as an open vented system. As usual, there is a corresponding drawback!
The overheat 'stat is somewhat prone to nuisance tripping and needs to
be re-set occasionally. The boiler will appear totally dead and lifeless
when the overheat thermostat trips and it is NOT obvious how to re-set
it. Nor is it obvious that it exists at all let alone might have
tripped. There is a hole about an inch in diameter in the underside of
the boiler, and deeply recessed in this hole is the re-set button. Have
a grope around the underside of the boiler and find the hole (next to
the fixing screw under a hinged cover), and press the recessed button.
If it clicks, just the once when you press it, the overheat 'stat was
tripped and the boiler will now work. If it won't click then it wasn't
tripped in the first place and the fault lies elsewhere.
And just to update this (29th January 2017), I've recently had a run
of call-outs to Potterton Profile boilers where the fault has been a
tripped overheat thermostat, and I've found the cause to be very simple.
The main thermostat sensor is attached to the flow pipe with a steel
clip. When the boiler reaches an age of about 25 years, this clip tends
to spontaneously break allowing the sensor to fall away from the pipe it
is supposed to be measuring. So the boiler continues to run, getting
hotter and hotter until the overheat thermostat trips. The fix is very
simple - fix the sensor back onto the pipe with a new clip!
The Netaheat Profile is an easy boiler to diagnose and repair (apart
from the heat exchanger contamination problem). Anyone telling you it
needs replacing because it's too old to get spares for is generally
fibbing in the hope of selling you a whole new boiler....
If you'd like me to fix your Netaheat Profile, contact me here.
First created 7th May 2011
Last updated 29th Jan 2017
Copyright 2011-2017 Michael Bryant