Copyright 2018, Michael Bryant
6/10, 10/16, 16/22, MkI, MkIIF, Electronic
One of Potterton's better efforts in my opinion. If you have one in good condition, it's well worth looking after.
A ground-breaking design originating in the late 1970's. One of the first (if not THE first) ever to have automatic spark ignition instead of a permanent pilot light, and a fan assisted flue. A major improvement in fuel-efficiency by forward-thinking designers in the days of plentiful north sea gas when no-one much cared about such things. An ordinary, natural draught boiler turns into a radiator heating the great outdoors when the burners are OFF through natural convection. Potterton decided to design a boiler that didn't do this, and therefore needed a powered flue. The NetaHeat was the result. 78% fuel-efficient in the days when 55% was typical, and many are still in use today.
NetaHeat Mk I (10/16 and 16/22)
A fan-flued boiler with NO electronics (well ok, there IS a simple electronic spark generator, but that's all). Excellent! All the main controls are electro-mechanical or plain mechanical. Very unconventional by today's designs, and almost impenetrable. I did manage to reverse-engineer the start-up sequence years ago when spares were available and I have a Word file of it for fault diagnosis should anyone need it. Email me if you do. Little point though as all the major control components are now obsolete and unavailable. If you have a MkI Netaheat the only commonly failing parts still available are the flue fan and the boiler thermostat. A great boiler though if yours is still working.
NetaHeat MkIIF (10/16 and 16/22)
Similar in appearance to a MkI and with the dame heat exchanger and fan but completely different and much simplified control components. A conventional combined multi-function gas valve now instead of separate components for each function. Little to go wrong with this boiler except the fan, thermostat or gas valve, and amazingly for a boiler discontinued 20 years ago, today all three of those parts are still available.
NetaHeat Electronic (6/10, 10/16 and 16/22)
A truly modern boiler. Still the same heat exchanger and fan as the earlier versions, but with full contemporary electronic control. The boiler all the other manufacturers eventually copied. Simple to fault-diagnose and repair, but sadly the gas valve is no longer available. All other parts are though. Common faults are fan failure, control board failure, erosion of the earth electrode on the pilot ignition. Gas valve failure is less common but still happens. No option other than to replace the boiler in this case.
All these NetaHeats are 'positive case pressure' boilers. This means the fan blows fresh air into the case and consequently, it is crucially important for the case to be correctly fitted and airtight. Crucial because there have been a number of deaths associated with the case not being fitted correctly. If the case is not fitted correctly inadequate air is supplied to the burners, leading to carbon monoxide in the combustion gas which essentially leaks out into the house through the gaps around the incorrectly fitted case. The importance of fitting case correctly is often not appreciated by people DIY-ing their boiler servicing, unqualified plumbers etc, and multiple user deaths eventually lead to this boiler being withdrawn from sale. The NetaHeat is a perfectly safe boiler when the case is correctly installed though.
A new boiler with 'negative case pressure' was introduced by Potterton to replace the NetaHeat. The "NetaHeat Profile" is a completely different boiler, just as good, but without the risks associated with incorrect case-fitting. The NeatHeat Profile will simply not run if the case is not correctly fitted. The "NetaHeat Profile" was later renamed to just "Profile". A first class boiler in my opinion.