‍Vaillent Ecotec Plus and Ecotec Pro:

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‍These boilers despite having a reputation for reliability, still go wrong occasionally. I know this because I’ve owned a few over the years and had the odd breakdown myself! 

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‍There are two distinct types of Ecotec boiler. The Ecotec Plus is a “heat only” boiler which means it runs a conventional radiators radiator and hot water cylinder system. The Ecotec Pro is a combi boiler which lights when you turn a hot tap ON, and needs no hot water cylinder.

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‍There is an early and a late version of each. The early versions have a (rather pointless) fold-down flap on the front of the boiler, covering up the user controls. The later version has no flap and the user controls are directly on the front panel. I’m not sure of any technical differences between the two versions yet - they look the same inside! 

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‍Edit to add:

‍There is however now a third version, a complete re-design, with a cast aluminium heat exchanger. The boiler looks pleasingly well-thought-out inside. Simple layout with good accessibility to the important parts. I’ve only seen. One of these so far but time will tell if its a good, reliable new version of the well-regarded Ecototec boiler. 

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‍Common faults and fixes:

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‍1) Error message F22 on display screen:

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‍This means the the boiler thinks the water pressure in the system is too low. This is often true as this boiler is usually fitted to a “sealed system” with no header tank, so any minor water losses from the system need to be replaced periodically by the user. There will usually be a “filling loop” fitted below the boiler, this being a silver-coloured flexible pipe with a valve at one or both ends. The valve(s) need to be turned ON for a short while until the F22 error code goes away then turned back OFF again. 

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‍2) Error message F22 still there after topping up:

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‍The pressure sensor in the Ecotec is terribly prone to blocking up if the system water is less than immaculately clean. Once blocked it no longer senses the system pressure correctly, or at all so F22 won’t go away. A new sensor is the best solution but removing and cleaning the blocked sensor may well get the boiler running again if urgent. Here are some photos showing a blocked sensor causing F22, and a new one for comparison:

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‍3) F28

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‍This is the dreaded and not-very-helpful “catch all” fault code meaning ‘Something went wrong and the boiler failed to light’ Well yes we know that already! The list of things given in the manual to check is massive but if the boiler has been working well until the F28 error started, lots on the list can be ruled out. Even then, the boiler failing to light at all is a different fault from the boiler lighting and running well for a random period of time, then inexplicably stopping and displaying F28, which can be cleared by re-setting and the boiler works well until the next F28 lock-out happens. Basic things for a gas technician to check on an intermittently locking out Ecotec are:

‍Gas meter not accidentally turned off
Condensate drain clear
Inlet gas pressure correct
CO2 level in flue gas correct at both high and low fire

‍No CO2 present at air inlet sampling point
Ionisation current (D.044) is within range

‍Earth path from burner back to PCB has zero resistance

‍Resistance of the HT lead is 1kOhm, not far higher

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‍4) F29

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‍This fault code is closely related to F28 above but it means the boiler flame failed and went out while the boiler was actually alight and running, rather than the boiler failing to light when attempting to start up. Causes of F29 are fewer, and will probably be one of these:
Blocked condensate drain
CO2 in the inlet air supply (long flue damaged)
Low ionisation current

‍Poor burner earth connection

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‍5) Burner door gasket failure:

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‍Not so common now but in the early days of this boiler (along with other brands if boilers using the same heat exchanger), had a flexible seal on the burner assembly door which failed allowing flue gas to escape into the outer combustion chamber of the boiler. The water vapour in the flue gas would condense onto everything in the outer chamber and spoil any or all components, sometimes wrecking the boiler. An upgraded burner door seal kit using a graphite-based seal design needs to be fitted at first service of any boiler still having this original flexible burner door seal.

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‍6) Flue failure:

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‍I’ve seen two Ecotec boilers with extended flues that have failed, leaking condensate. On both Ecotecs the seals on the inner (exhaust) tube started leaking condensate into the outer air supply tube about five years after installation. On one boiler the leaking condensate corroded directly through the outer air supply tube and was found during a landlord gas safety inspection. On the other, the condensate drained via the air supply tube back into the boiler causing a breakdown by damaging a sensor and corroding through some conductors in the wiring loom. In both cases a whole new extended flue was required and in the latter, a new wiring loom and sensor. Both were expensive repairs.

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‍If you’d like me to visit and fix your Vaillant Ecotec, get in touch. My number is 07866 766364. (A text to this number reaches me quickest.)

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