I have just had a Vaillant ecoTEC plus 418 (or 'plus nothing but problems!). My housing association used their usual corgi registered company to install it and it has not worked properly once. After pressing the flame button it starts up and shuts down several times within a 5 - 10 minute period, have pressed (i) which often shows S.98. Then it shuts down completely displaying error F.23. Had the engineer back to figure out and fix problem, but i'm not sure he knows much more than me. Said it was probably a bit of air in system, bleed the radiators and if it happened again then just to press reset (flame) button. Well, every 5 - 10 minutes is ridiculous and after so many times S.7 (overrun fan) displays and shuts down. What, if anything, can i do? Housing Association and Engineers have not been much help so far, and they've just increased my rent!!!!!!!!!

sheilamurphy13, April 2009

One problem I have with the ecotec, is that the boiler does not respond well to load changes.....if the heating demand turns off, but the HW is still on demand, the boiler often trips on high temperature...runs on for the set duration, then fires up too fast and trips again, eventually it settles down, or the cylinder is eventually satisfied....the HW circuit is very small and the cylinder is very small also. I was running the boiler at 85oC to give a better differential, which works better, but the return temperature would be too high for condensing mode.....

Works perfectly with heating, as the demand is a lot higher...

What I would like is to have a different tuning / response when on HW only.....with the HW module would this be a possibility ?

RedDOTdwarf4everATyahooDOTcom

Steve jones, January 2018

I also have a 418, had no end of problems when first installed, the installer, said the run on wire was nothing to with him, so I arranged this to be fitted by someone else the following day. Kept tripping out with lots of noises, the installer kept trying to bleed the air, then said he could do no more and left me with it.....it did settle down eventually and with the run on wire, at least it wasn’t getting damaged...my plumber suggested that the CH makeup tank overflow be joined to the supply pipe, this he said is perfectly ok but will stop air being sucked in.....the CH plumbing goes round the houses, as when I had an extension built, the piping wasn’t done as well as it could have been.....any way with this plumbing mod I get virtually no air at all...

The heat exchanger was replaced under guarantee as it kept making whistling noises, now ok also.

One problem I have with the ecotec, is that the boiler does not respond well to load changes.....if the heating demand turns off, but the HW is still on demand, the boiler often trips on high temperature...runs on for the set duration, then fires up too fast and trips again, eventually it settles down, or the cylinder is eventually satisfied....the HW circuit is very small and the cylinder is very small also. I was running the boiler at 85oC to give a better differential, which works better, but the return temperature would be too high for condensing mode.....

Works perfectly with heating, as the demand is a lot higher...

What I would like is to know is could I have a different tuning / response when on HW only.....with the HW module would this be a possibility ?

Steve jones, January 2018

Installed 5/12/2016 since then central heating crashing every day with fault code F23-F83-temperature spread too largeT23.etc -etc.expansion vessel was also due to be installed on the 5thDec 2016 didn't happen -northerngasheating was due to return 6/12/2016 but did not .Still waiting --no heating .Advise needed urgently

Veronica easterbrook, December 2016

I got the same problem with the boiler I'm on now, as I contract to British Gas these are the boilers they install, they are crap for trapping air, I've tried many things I.e pulling air through the radiators from the boiler adding air vents but still the problem persists, I'm pretty sure the electrician has wired the pump in wrong so I'm gonna see what it runs like if I connect the pump to a plug an then run the boiler.

Andy, May 2016

Hi Guys just seen this as i'm a gas safe engineer and i have installed one last week and having the same problems you all have had, after much pissing about & many conversations to vailant the problem is that you don't have a the pump overrun connected to the pump from the boiler which i didn't (the old boiler you had may not have needed it), for example your boiler has to have a new Wire from your boiler to your pump which the boiler will use to keep the pump on after demand to clear the heat from the boiler hence why you keep getting the overheat fault and cutting off on the safety stat. Like in my case this is an absolute nightmare as i have to run a new wire from the boiler to the cylinder cupboard which is an absolutey horrific and with a winging customer to boot saying she wan't no carpets removed/boards up, if i had known this i would have picked a boiler without the pump overrun required fecking disaster

Mcwoodbert, February 2016

You need to make sure you have sufficient water flow! Low water flow is the main cause of problems with this boiler. If you can turn up the speed on the water pump to Max and run boiler at full demand. You will find it runs without problems as its getting all the flow it needs.
Yes you may get more noise from the water flow. You can try reducing flow in steps to find the right balance if you have a variable flow pump. If not you will need to pick a speed that supply sufficient flow to keep boiler working within design spec.
Low water flow results in boiler noise (ketling) and poor control as boiler overheats and switches off and on too many times.

Pongdot, November 2015

I have literally just had a brand new Vaillant plus 418 installed this weekend and it wont run. After a minute or so the F23 error code appears and the boiler shuts off. It was to replace a boiler that was 28 years old. The error means, water shortage, temperature difference between flow and return NTC too large. According to the manual, this can be a number of reasons, pump blocked, insufficient output, or flow and return NTC interchanged. I am fed up, new boilers are meant to work not cause more problems than the original.

Fed Up, November 2014

i have one of those, its a nightmare, same problems but mostly s.7 which according to the manual the pump is overrun. I think this boiler is a rip off. I wasted hours and hours reading the manual and calling the engineers. Useless machine

p, October 2012

Either the pump has seized located near your hot water tank. Or your heat exchangers are blocked & your system requires a pressure flush & a magnetic filter installed to stop it reblocking. Had it all done for £335.00. That included inhibitor fluid. British Gas quoted £1300.00. My plumber was honest & saved me £965.00. Good luck.

Eric Beazley, March 2011

pump or pressure sensor needs changed....did they fit to existing system ??? If so they should have fitted magnaclean.. Vaillants are great but only when fitted with maganacleans.....otherwise any little bit of crap in the system will shut it down.........

The big A, March 2010

I have bad experience since 25 December just keeps boiling on hot water central heating fine connot seem to control.Ihavehad lots of visits by Vaillant engineer even had new gas exchanger and waterheater unit they set it up it works then surely the next morning on start up it will make slight noises bubbling next day proggresivley worse .I have had my plumber back lots of times carried out relevel pipes in the loft put a By Pass on, fitted air vents extra keeps coming back to the boiler am about to check time delay on pump opening actuator ie three port valve am more than convinced that the flow is not at the boiler or significant enough to allow the heat to bepushed round the exchanger my test this afternoon is to run off hot water let the boiler cool for 1hr and restart .I discovered this morning that when boiler calls for heat there is only 1min to activate pump flow then threeport valve untill that changes you won,t get flow so in respect getting adequate flow on start up first thing in the morning cold as well iv,e had lots noise.I once past the noise and and initial heating its fine.Its very annoying traumatic you still have your rights .Once again its a funny sick world because I believe the vaillant engineers get paid per call out so they milk vaillant with pleasure who never ever get the details do you ever have to sign anything NNo.stand on your rights my plumber likes to think he knows he only seems to emagine all the existing pipe work has air locks and is out of level more work what a supprise.tell them to take it out as its not fit for purpose make them think.Thats what I will do .

Clarence, March 2010

have a look at this http://www.vaillant.co.uk/stepone2/data/downloads/d4/42/00/ecoTEC_plus_open_vent_installation_and_servicing.pdf

sparkybloke, June 2009

if u can get to the pump turn the big screw in the middle take the air out plus cheak the impelor in the pump is running free

billy, April 2009

contact the manufacturers if the boiler is under 12months as it will stil be under garuantee

STE, April 2009