Are you looking for help with your faulty Vaillant boiler?
Dealing with a faulty boiler can be stressful, especially when you have to decipher fault codes and are left feeling unsure of what the problem actually is. Over the past few years, I’ve dealt with many Vaillant boilers and know most of their faults inside-out, which is why I decided to write this blog post to help you out.
Below are five of the most common faults and fixes you can try for your faulty Vaillant boiler, either yourself or with your local Gas Safe registered engineer.
TIP: If you’re in any doubt, or it’s not an easy fix such as low pressure or a frozen condensate, DO NOT try to fix the boiler yourself – always call a professional Gas Safe registered heating engineer.
About Vaillant boilers
The original inventor of the combi boiler, Vaillant has been at the forefront of German heating and engineering excellence for the past few decades. Well-known for manufacturing boilers that last the distance, they’ve also won an award for making the quietest boiler on the market, so great for installing in bedrooms.
Vaillant has their own dedicated service engineers, and more recently have made a large investment in Scotland by building a dedicated training centre.
Common fault 1: Code F22
If you see the code F22 show up in your display, a quick check of the manual will say something alone the lines of ‘dry fire, insufficient water’. This indicates your water pressure is low, which happens to be probably the most common boiler fault of all.
The Fix: This is an easy fix for most boilers with an external filling loop; simply open the little tap around a quarter turn until the display on the unit hits 1.5 bar, then close the tap again. You may have to reset the boiler. However, for Vaillant EcoTEC Plus models, it’s a little different, as they use a built-in filling loop.
For EcoTEC Plus models, look below the boiler; there should be two grey levers which will have ‘closed’ written on them – each should be sitting at the ‘quarter to 3’ position (if it were a clock). Open both of these valves a quarter turn, so you won’t be able to read ‘closed’ – they should now be at the 12:30 position.
Once the pressure returns to 1.5 bar, close the levers and reset the boiler.
Common Fault 2: Code F75
If the code F75 is flashing in your display, the fault is most likely to do with the boiler’s sensor not being aware that the pump has started running – so failing to notice a change in pressure. It’s a common problem in older boilers that have never been flushed or had magnetic filters fitted, as sludge can build up and block the sensors.
The Fix: The easiest solution here is to simply replace the sensor.
Common Fault 3: Codes F27 & F28
These codes refer to a frozen condensate pipe, meaning the condensate waste cannot run to the drain and is trapped in the boiler, causing the boiler to lock out.
The Fix: You may have to wait for the condensate to defrost. If the pipe runs outside, pour hot water over the pipe to defrost it, or place a bucket under the boiler and disconnect the plastic waste pipe on the far right of the boiler, before draining the condensate into the bucket.
Common Fault 4: Code F28 (Vaillant Turbomax)
This fault, particularly common for the Vaillant Turbomax, is caused by a faulty ignition, or no gas getting to the boiler.
The Fix: Firstly, check the condition of the ignition leads – is a spark being generated? If not, you should replace the ignition leads as this may fix the problem. If there is a spark, check the power to the gas valve and see if gas is flowing through. If there is power to the valve, but no gas flowing, it may need replaced.
Common Fault 5: Code F29
If the code F29 flashes up, the manual will probably tell you something along the lines of ‘flame extinguished’.
The Fix: If boiler is igniting, and then shutting off, check the flame sensors, flues and airways. You may have to replace the sensors, and the seals on your flue. Check your flue, extensions and bends are connected properly and have not come apart.
Conclusion
I hope you’ve found this blog useful when troubleshooting your faulty Vaillant boiler, but remember, unless it’s an easy fix such as low water pressure or a frozen condensate, it’s best to call in an registered Gas Safe registered engineer who has experience dealing with Vaillant boilers.
If you have any questions or are currently experiencing problems with your Vaillant boiler, please don’t hesitate to get in touch with me directly or drop me a comment – I’ll be happy to help!
Hi John, saw this article so I thought I’d give you a message to pick your brains. I have a Valiant EcoTech Pro24. Age I reckon 4-6 years maybe. The hot water works fine when I call for it but when I ask for Heat the flame comes on and after about 30-40 seconds it goes out. The boiler continues to whirl but the flame does not ignite again. The water in the pipes become unusually loud about a minute later. I’ve been told by the help desk more than likely it’s going to be the PCB? Any thoughts would be appreciated? Thank you
did you ever get a response to your q as i have exactly same issue and was told it may be a faulty pump?
Hi. I’ve got a vaillant turbomax that keeps throwing me an F28 error code. Have changed the PCB and associated lead and the gas valve. But still I keep getting this error code. To get hot water I have to reset and then run the hot water. Any comments gratefully received.
Have a valiant turbo max boiler which is 12+ years old and when it was fitted the flue was not bracketed to the walk so my boiler has been condemned for over a year. We had to use the boiler as joule not afford to get someone to fix the flue but now the boiler is not working properly as we have hot water but no heating someone came out and said it was the diverted vaulve which was broken and needs to be changed. Could you please give me a rough estimate hoe much it will cost to bracket the flue and put in a new vaulve . Many thanks
Hey, I recently installed a Vaillant Home Combi 35.
It has a VRC 700 controller, which I have taken 2 wires from the boiler to the controller. I have a weather compensator wired from the boiler to outside. Then 230v L-N-E from a fused spur straight to the boiler.
I have power at the boiler, and the controller. An when I turn a tap on, it kicks the boiler up and gives me hot water. The problem lies when I try going to the controller and turning the heat up for the radiators, which stay Luke warm and just don’t heat up. The radiator symbol also isn’t shown on the boiler screen.
Any help would be appreciated.
Fill the water over 1.5bar what shall I do
I have a turbomax about 10 years old stated coming up with F22 fault but pressure above 1.5 bar
Changed the 3 port valve and pump but still comes up about every 3 days
Hi. I have Vaillant ecoTec plus 831. Last night it felt chilly and I moved the boiler control to a slightly higher temp setting (65). This morning with the boiler on, I noticed that the needle on the pressure gauge was right over to the farthest point on the red section. The digital display showed the pressure to be 3.6 bar. Now, with the boiler off for approx two hours, the boiler temp is 41 degrees. The needle has dropped back into the mid point of the grey section. Digital display shows 1.5 bar.
Any suggestion as to why the pressure went so high. I checked the boiler fill loop and both vales are off.
hi needs an expansion vessel most likely.
Whilst changing these, its worthwhile replacing the `PRV`.
Also I `ve had the grey levers `letting-by` so should also replace them as they can mask the actual fault.
a few times lately the clock on my ecomax boiler has lost one hour over night so the heating did not come on we think the boiler is about 10 years old
I have
Water goes cold after about 4minutes
Hi,
I have a Valiant Eco Tec 637 , which is off , showing Fault codes F28 ignition failure and also F54.
Can it be helped ? My fiddling with water pressure and trying only show spark but no sustained operation.
Thanks.
AJ
Hi I have like warm water and luke warm hot water
At best
On the display it has a egg timer displayed
The boiler read it get to 30
At times goes to 59
Then drops straight back to 27
Hi, I have an Ecotech Plus 428 boiler installed in 2007 along with a complete replacement of water pump, regulator, room thermostat , timer and radiators . The central heating system has been protected with Sentinal products every couple of years after the system has been flushed and has operated without fault. Servicing is also done annually. Recently however the boiler has started to switch to Anti-Cycling mode (fault code S.8 or S.28) -which then rapidly cools the central heating and water down . The pump remains on for a while but the boiler doesn’t fire up for about 5-10 mins . When it does fire up it reaches the temp setting on the dial currently set 65c and then goes into anti-cycling mode once more. Is this an electrical fault or is it something more sinister?
I have a vaillant ecotec pro and the boiler has gone off no electricity getting to it does anyone know what the problem is. its only just three years old
Hi there, I am a frustrated Vaillant Thermocompact owner which is 19 years old and has been brilliant, serviced and loved. It is now driving me crazy. It all of a sudden fails to fire. The first thing I know is that there is the red illuminated light at the top of the light bar that shows you what is going on. I have to refire it with the switch. It recently had the PCB board (?) replaced but that made no difference and so the old one went back in. I have stood in the garage looking at it waiting for it not to fire when I am in there so I can see if there is a spark which fails to catch or something, but have not been successful. Any ideas please as my heating engineer is at a loss too.
Hi Jo Paynter
Mine is 20 year old the 242 E model and just had the same issue .we changed the Flow switch ( Vaillant 151041 cost £30 ) now all working again
hope this help
Hi John, when I call for heating on my Vaillant ecotecplus 824 it seems to take 20-30 mins before it goes to full fire. In the meantime the radiators are lukewarm. The water pressure is ok and radiator symbol on the panel flashes as it should. Any ideas before I call the engineer to have a look as it’s quite annoying when the house is cold
I have an ECO PRO 24 and I notices this morning the hot water pressure is very low upstairs in the bathroom. I turned it on and it starts off ok then goes to a trickle. The water is hot. Downstairs is fine and the cold water upstairs is fine. I have checked the bar level on the boiler and its fine. Any suggestions?
Why does the outer case of my boiler get too hot to touch is this dangerous
sir
i have f 70 invalid device coming up on my valiant boiler
some days ive got hot water and heating and some nothing
can you help please
Hi i have a eco max pro that has fault code 11 flashing and its turned red can you advise me ? Much appreciate any help thx
I have a eco max pro with fault code 11 flashing and its turned red. Can you advise me. Appreciate any advice. Thx
Ihave a Eco tech pro , it keeps losing pressure , its about 10 yrs old , i have bled the radiators , but to no avail , it still losing pressure , any ideas ?
I have an valiant ecotec and after a power cut noticed the boiler was not working on inspection found a fault codes of con I wonder if you can tell me what to do
i have a Valliant condenser boiler, with the central heating on and the hot water off the hot water comes on of its own accord intermitentlly to an excessively high temperature. During this time the indicator light for the hot water is off. I have had a certified engineer to look at it but he cant find anything wrong
Merry Xmas and a Happy New Year
Glaslyn.
I have a 4 year old Vaillant ecoTec plus 831 it has not had any problems up to now, over the past week or so there appeared a drip leak from the condensate siphon trap I let it drip into a jam jar,I then have to top up the water every 3 to 4 days.
I can’t seem to find the part number of the siphon bottle. The trouble is the BG fitter who installed the boiler put a pipe right under the siphon bottle.
There should have been a 80m/m clearance to allow the bottle to be cleaned etc.
I am unsure as to the responsibility of BG in this matter, I think they should repipe the afending pipe under the siphon trap.I would be very much obliged for any help with this problem.
I hv valliant ecotec pro 28 r1.while gettg water level through valve.if we dont move the valve back down aftr water level is up.what can happen vid it.can it cause major damage.
Hi, I have the Ecotech Plus 837, and have just found out after two years of using this system, that after refilling, the filling pipe must be again detached at the double check valve.
The filling pipe has always been connected, and I have not had any issues, but I am concerned after reading the manual that it might damage my boiler.
Any info would be appreciated.
Kind regards Chris
Thank you!
I have a vallant turbur 0242E that is loosing water which comes out of the overflow outside whats the prob? and how much will cost to fix
Hi I have a turbo max plus 824E. I have called my engineer to check the boiler as the pressure was dropping to 0 after filling up the system with water. after about a week the same thing happens. the boiler still works but the pressure is on zero.
Any suggestions
What does a F83 fault NTC temp gradient mean on my Valiant ecoTEC plus 430 mean?
Hi
First of all excuse me my english.
I have a Vaillant 182e. In summertime it runs without faults, but ind winter when it gets cold alround 0 degres the boiler goes on lockout. There´s no rytme to the faults as they just accure.
I have notice that the flame insite the boiler becomes smaller as it goes. Could it be that the boiler gets too hot or simply suffercates
I’ve got hot water but the heating do not come on
Hi John,
We have a the ecoTec plus 824. It’s showing F22 almost every day and I have to manually reset the pressure using that two levers. Any idea where to look first?
Thanks
Peter
Hello
VRT 360f boiler is showing BMU Err.
Boiler window has flashing radiator symbol.
Please can you advise
Thank you
Hi John,
We have a ecoTec plus 824. F22 error is showing and there is no pressure almost every day since the heating is on longer. I have to manually reset it by turning the two gray levers.
Any idea where to look first?
Thanks
I have a valiant ECO Tech Plus Fitted 2009.
It supplies hot water but no heating. no fault codes showing.
I have bye passed the room state in the boiler with no change.
Could this be the circuit board?
Vaillant Ecotec 831. Central heating works, DHW does not work. If I leave Comfort Mode turned on, it’ll produce some hot water and then run cold — water heating on demand doesn’t happen. No fault codes showing.
Hi, I have an EcoTec Exclusive which is intermittently making a very loud grating, vibrating noise. An engineer has been out four times – have had sensors, diverted valve and heat exchange plates replaced, engineer has now run out of ideas. There is no particular pattern to the noise, and will happen under different circumstances each time. I have checked display, there are no fault codes coming up, sometimes it says “heating over run” and sometimes “OHV mode”. Any help at all would be much appreciated as now running out of money and patience! Jennifer.
HI John, I hope you may be able to help.
I have a Vaillant ecoTECpro 28 boiler installed Nov 2012. I have recently been getting F22/0.0 bar displays and no heating or hot water. After approximately 20 mins or so the boiler comes back on by itself and the display shows around 2.3 bar. Heating and hot water back to normal. NOTE: I have NOT tried to top up the boiler via the filling loop. This has happened three times in the past twelve days.
My local installer says they can not find a fault especially as the system is working normally when they attend!
Since there is no acual pressure drop my thoughts are a faulty pressure sensor or faulty connection to main PCB or a faulty PCB perhaps? Any suggestions from you please John or anyone else having the same problem.
Thanks
Water Temp set at 35 but Water still comes out at Scalding Point when the CENTRAL HEATING IS ON, when off, water returns to normal, i would run it at 40,. What should i do?
I have an eco max 835e
The display panel shows 79 to 80 dog all the time even when cold what could cause this to happen?
Thank you
Hi John
I am experiencing a problem with my Vaillant 838 combi boiler which keeps tripping out the RCD, it seems to be an intermittent fault that usually occurs when the outside temperature drops below 5deg.C.
The boiler has tripped the RCD twice today but the strange thing about it is that when I reset the RCD switch the boiler starts up and continues to run ok.
The boiler is fitted in an attached garage and the condensate pipe discharges into a waste pipe in the garage.
I have looked at the recent recorded fault codes recorded which are F22-F28 and F75.
Have you any thoughts on what might be the cause of the RCD tripping out?
Hi, I have a 5 year old Vaillant ecoTEC plus618 which was serviced on 30th November. 16. Having been away for two weeks over Xmas leaving heating on tick over I found that the flue had been leaking. It only appears to leak after it has been boiler has been working. The top of the boiler is now rusty and water is running down the rear. What do you think is the cause. The boiler is still I working very well.
MY VAILLANT MINI 11-01 RED LIGHT FLASHES AND THE WATER GOES COLD WHEN I AM IN THE SHOWER HAVE REPLACED GAS BOTTLE, MANUAL SAYS THERE COULD BE AIR IN GAS SUPPLY BUT HOW CAN I STOP THIS OR ANY OTHER IDEA’S PLEASE
Hi John. We have a Vaillant EcoTec Pro 28 combi boiler fitted 5 years ago. Recently we have a fault F22 every morning which is fixed temporarily by letting in a little water until the pressure rises. We obviously shouldn’t have to do this everyday. The only other thing is that water is coming out of the outside overflow on a regular basis. Any ideas on what is wrong? Thanks.
Hi I’ve just had united utilites to check water they said only deal with cold my hot is coming out white why ? I have a valiant boiler ?
Hi There
I have a vaillant turbomax 828
Initially i started getting luke warm/hot/cold water in the shower. So a plumber said to change the heater plate, did that and problem still stayed. I then was told to replace aqua pressure flow sensor. After doing that the water is continuosly cold with initial warm water for few seconds then really cold. Boiler does not fire up after this and i get error code f29. However if heating is on all is well no codes no firing issues etc.
So now no hot water let alone luke warm. Any help greatly appreciated TIA
Hi, Great article, I wish you guys were down south as you seem to understand these boilers very well.
I have an ecotec 838 exclusive, Its running two central heating zones, but when either zone requests heat it seems to take a long time to heat up and the screen is constantly showing overrun and water deficiency messages. Generally it fires up runs for a bit, temp gets up to 65, then goes into overrun or water deficiency and basically cycles like this for 2 or 3 hours to get the zone up to temperature. Sometimes, maybe every 2 -3 weeks it can also shut down completely with a F23 over temp spread message, this requires a boiler restart to clear. I have a magcleaner fitted on the return, 7 rads on zone 1, 6 on zone 2, and 1 on the pre zone loop.
My gas bills are really high and I’m wondering if this boiler is trying to tell me something?
Would love your thoughts on this.
Cheers.
Hi
I have a vanilla tea exoteric pro 28 and last night noted that it had switched off at the mains and when I turned itback in and refilled the tank and the bar went up I though it was ok until I noted the thermostat and the boiler were not communicating and the heating is on permanently. What do I do?
Hi. I have an ecotec plus 831 boiler. When we have the heating on the radiators seem to take a while to become hot, also the little graph symbol on the boiler shows the burner to be operating at a very low level. But shoots up to about 9/10ths when a tap in the bathroom is turned on. Is this normal?
No fault codes are displayed and the system pressure remains at around 2Bar, but the house seems to take quite a while to warm up. Boiler is just over two years old and has been serviced as recommended.
Many thanks for any help.
Len.
My Vaillant ECO tech plus lost pressure. I have fixed this although I did do it too high …2.6 rather than bar 1.0. The heating is fine but I have no hot water. Water comes out of the hot tap then trickles off. If I turn the shower to cold water, water flows well from hot tap but it is cold. When I turn shower back to normal it makes a whirling sound for a few seconds and then no water will come out of hot tap. I don’t know what to do. I have no water from any hot tap.
Have you shut both filling valves off?
I have a Vaillant ECO tech boiler – 2 years old. This morning when heating didn’t come on I notice the pressure was down. I have fixed this but instead of raising level to bar 1.0 I raised it to 2.6 but understand this is o.k. However, I have no hot water! it trickles from the tap then stops and is cold. I have no water from any hot tap. If I turn indicator on shower to cold, I get cold water from the hot taps. When I return indicator to normal there is a whirling noise and water ceases to come out of hot taps. I just don’t know what else to do.
F73 error, Hi, we get this error on the panel, i had someone have a look at it, they said the PCB needs to be replaced, no 240V and one of the live wire on the connectors looks black? he said £300 for the PCB plus £250 labour. Does that sound right?
Hi I have a eco tech plus 831 vuwgb316/5/5r2 boiler with a fault f28
had a new ignition probe etc fitted still no joy.
the condensate is inside and connected to the internal drain under the sink and water is passing with good flow so not blocked.
intermittent voltage on gas valve causing on off of burner.
would it be safe to say its the PCB not the gas valve ?
I am a at loss to what it could be if not the PCB….
date 08/02/2017
My valiant combi boiler is showing sign of 2.8 and it is flushing
Hi i have a vaillant eco tec boiler that was fitted by a government grant for my elderly parents for about 3 months know the hot water comes out luke warm regardless of the temperature set and the boiler makes a whistling sound when hot water tap is being used and carrys on making noise for a minute or so after tap is off
Please help
I’ve just changed the pressure relief valve and connection tube on my vaillant turbomax vuw 242e But when I turn hot water tap on when heating is on I get a buzzing nosie didnt have it before what’s the problem many thanks
Hi my valiant boiler is having fault f28..but as soon as I reset that button it goes to normal again.This happen only when water is cold or weather is cold.
Hi there.
I have a Vaillant Turbomax Pro 24 E. The heating has stopped working altogether. The hot water is still working. The pressure is reading zero (I haven’t looked at this for a while, unfortunately). There is a silver filling loop, with one valve attached at one side (but no valve on the other side, as I’ve seen in videos on youtube).
I did turn the single valve, and heard a noise, but after a good 10 -15 seconds, there was no change in the pressure gauge reading and I stopped in case I made it worse.
I’ve just spoken to a gas engineer by phone and he told me that it wouldn’t be the low pressure that was causing my heating to not work….is this correct? He thinks it’s either a diverter valve or the thermostat.
Any help would be very much appreciated.
Thanks
Hi
I have a vaillant ectec boiler, the t140 programmer is playing up.
The F button to overide the currant heating/water is not working.
Do I need to buy a new one.
i have a vaillant VK654/9 – 1654/9 there is a beeping sound and a voice saying low battery, I cannot find were the battery is located.
Hi there,
I have a Valiant ecotc plus831 R1, about 6 years old, it was always working fine till now . The pressure keeps dropping down to 0 , I turn the pressure gauge around and brought it up t1.5bars,
And each time I turn water tap in kitchen sink on, it stays cold and the radiator gets very hot.. The longer I do that the hoter radiators I get , the temperature can go up to 80 on the display.
Please can you tell me what to do?
Thank you
I have a vaillent eco pro plus about 7/8 years old no hot water or heating screen completely blank changed fuse screen flickered for a couple of seconds went blank again any ideas please
Hi. I have a vaillant eco tec plus 831. I have no display, no heating or hot water. I’ve had a electrian out to check power to boiler, all ok. Someone told me to get a new pcb but first to check flue fan and pump are free spinning. I’ve looked at a manual and can’t work out how to do this. The plumber I use is away, so was hoping to see if I can fix it myself. Thank you in advance.
Hi. I have recently bought a new house that has a vaillant economic TED plus boiler. It works ok but is really noisy. I can hear it whirling all night and day even when there is no heating on or water being used. It’s starting to drive us mad, it almost sounds like the noise a fridge makes but constantly – we have even switched off fridge to see if it was that!! I would appreciate any advice.
Hi ihave a ecotec pro 28 its fine on hot water, but will not ignite on heating ,
My VaillantATMOMag11 hot water boiler that has recently been changed from Calor gas to Natural Gas, however since the change over I cannot get the taps in my bathroom or en suite to give me hot water
Although the showers in both rooms does give hot water. Also in my Kitchen the hot water from the sink tap is working perfectly. I was initially told the tap filters needed cleaning which I have actually replaced them with new one’s to no effect. If I was getting hot water from these taps previously why cant I get hot water now?
Hi, i have a 3 year old vaillant ecoTech pro 28. until recently i have been delighted with it. however, it has suddenly started doing its own thing! the water has always reached 80 degrees and suddenly it has started being choosey about when it will do this. also, the radiators come on even when they are turned off at the boiler.
i have had it serviced twice in the last 6 months. the last chap told me that as the thermostat is wireless, any thermostat that is also wireless, within 100 feet, can affect it. so, i moved the control right by the boiler, but it is still happening! does anyone have any ideas?
I only have hot water when the heating is on!
Hi, f22 comes up, tried using the valves to resolve it , not working? Water both sides of valves, just not filling? Two doors on boiler on zero As well? Any ideas? Phil.
I have eco tech pro. I leaked from tne bottom of the boiler for about 5mins and stopped. What could be the problem. Shoulc I worry about this.Many thanks.
My Valliant combo is leaking–drip, drip. Called plumber and he said I should change it–does a new boiler really take one full day, 2 people, to install?
Hi, I have a Vaillant Ecotech Plus 824, and I’m getting F28 and F54 message. Gets serviced yearly. Thankyou.
Hi,
We have a vaillant Eco TEC plus 438. We put it off whilst on holiday for 3 weeks and when we put it back on heat and water the radiators got hot but the water did not even though the towel rail in the bathroom that works off that circuit did. This morning the boiler will not light at all and we have an error code F20. Any ideas?
Thanks
Hi there, I have an ecotec 837 plus boiler, fitted in 2012. It failed to fire, so I had a Valiant engineer out to repair the problem. It wasn’t the boiler itself it was the flue leaking water back into the boiler causing it to fail. The part was replaced and the flue was renewed by a corgi registered engineer. A few weeks on l’ve noticed water leaking from a 90° bend indicating the same problem. Any idea’s ?
Many thanks
Get the gas safe registered installer back in. Either the flue isn’t all the way in the 90 bend, or the seal was damaged at the time the new flue went in.
I’ve got an 831 plus that I set on the timer. The heating comes on at the right times but also chugs on and off in between. I’ve had it recently serviced and was told no problems, to be careful with the pins. I’m definite they’re all pushed correctly.