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Vaillant Eco Tec Plus 637 - issues

Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws

S

santhosh

Hi All,
I had the central heating system replaced recently, the set up is below
Vaillant Eco Plus 637 system boiler
Excelsior hot water unvented cylinder
Honeywell timer - ST9400A/C
Honeywell thermostat
I have the below issues:


Boiler will turn on and off as per the timing set in the timer, but once the timer goes off say about 20 mins later boiler starts again and runs for a minute and turns off whilst the fan continues to run for another 10 mins (fan in the boiler operating for 10 mins after it shuts off is normal I believe) but this continues round through the clock day and night when the timer is off.


There is no ho****er mode in the display on the boiler, pressing the left button doesnot show any settings for the ho****er mode and radiator icon is always on and flashing suggesting that the boiler is in central heating mode and pressing the right button shows the settings for target flow temperature and water pressure. The fitter says ho****er temperature is controlled using the thermostat on the ho****er cylinder and in system boiler there will not be any settings available from the boiler. But the manual doesn't say so, they say all is well but I doubt it.


I have provided the images of the boiler display panel, thermostat, ho****er cylinder and timer below, please answer my below questions:
1) Should the System boiler have hot water mode or not? should the tap icon be shown on the display panel?
2) will the frequent start and stop of boiler (once every 20 mins) wont affect its performance? and is it normal as told by the fitter?
24109-1.jpg 24112-1.jpg 24113-1.jpg 24115-1.jpg
Thankyou,
Santhosh
 
yes, it were all fitted just a couple of months back. Do you think there is a problem with the boiler?

Thanks,
 
Hi Santhosh
So it is a large property that you live in then ?
You have asked the original installers to explain what is going on what did they say ?
what's with the "ho****er", an I missing some thing ? what do you mean.
 
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chris watkins said:
<font color="#333333">Hi Santhosh<br>
So it is a large property that you live in then ? <br>
You have asked the original installers to explain what is going on what did they say ? <br>
</font><font color="#333333">what's with the "ho****er", an I missing some thing ? what do you mean. </font>
Click to expand...
<br>
<br>Hi Chris,<br>
Thanks for the reply, well its a normal 3 bed house with a downstairs shower room. hence opted for mega to ensure hot water is available at both bathrooms and kitchen simultaneously.<br><br>As per the valliant manual, there should be two modes in the boiler one each for hot water and central heating. Pressing the left button should display settings for hot water and right button for central heating. but on the display panel (see the attached pic) I don't find hot water icon (tap) I see only radiator displayed always and radiator icon flashing when the boiler is on this suggests to me that the boiler is in central heating mode. But the fitter says in system boiler there will not be any settings for hot water at boiler and the temperature needs to be set at the thermostat on the cylinder.<br><br>Second issue I have is, the boiler starts once in every 15 - 20 mins for a period of 1 min and switches off itself which means the fan with in the boiler will start running for the next 10 mins. This is results in constant noise and the frequent on and off of the boiler round the clock will reduce its life span as well.<br><br>hope I have explained it clear.<br><br>Cheers,<br><br>
 
Sorry for all the questions but just trying to get a clear understanding of your situation, who selected this 37kW boiler ? & when the installation was compete did the engineer not provide a client demonstration as to how the system was installed & to be used ?
 
chris watkins said:
Sorry for all the questions but just trying to get a clear understanding of your situation, who selected this 37kW boiler ? & when the installation was compete did the engineer not provide a client demonstration as to how the system was installed & to be used ?
Click to expand...

Fitter suggested the 37kw boiler after calculating the radiators and bathrooms, he also suggested all of the other components (timer, zone valve, thermostat) when the installation was complete, he instructed us how to set the timer for hot water and central heating. Tested it by setting the time for 10 mins ensured the timer is turning on the boiler and switching it off as per the time set in timer, we checked all the radiators to ensure heating was fine. But once he left the boiler we noticed the boiler is turning on every 20 mins for a period of 1 min it's happening round through the clock. That's when I started digging into the manual and posted on this forum.

I feel the either the boiler isn't configured properly or the fitter has cocked up the installation 🙁
 
To me that boiler is way too big but without know the details of the house I can't say for sure.

Get him back ASAP to sort the issues out.
 
Last edited:
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Howsie said:
To me that boiler is way too big but without know the details of the house I can't say for sure.

Get him back ASAP to sort the issues out.
Click to expand...

well its a three bed house two doubles and one single, with lounge (12 *15) dining (12*12) downstairs utility and shower room (12 *10) kitchen in the rear 3m extension all together we have 9 radiators.

Did speak to Valliant this afternoon, they say the boiler should come on and switch off as per the timer settings and not at other times, if its doing this once every 20 mins then there seems to be a problem. Since it is in warranty they will be sending an engineer this thursday, will update the post with the outcome.

Thank you guys
 
As above, it is likely that the boiler is twice as big as is required for a normal 3 bed house, unless you have the biggest rooms I have ever seen or 10 living rooms downstairs.
The boiler will not be able to run correctly with such a low heating load & will keep entering an anti-cycling mode.
The hot water thermostat on the boiler is only activated (& used) if you use there un-vent cylinder or buy the cylinder temperature sensor if i remember correctly.
Ask the installer to come back & sort out these problems to your satisfaction. (please also make sure that the installation has been notified to both Gas Safe & the manufacturers by your installer).
Hope that helps a bit.
 
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Please don't wait for Vaillant to come out, ask the installer to come back first, if it turns out to be a problem with the boiler let them call them out.
Pound to a penny it is not going to be a manufacturers fault !!!
 
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doesn't the ecotec plus 637 system have an aquacomfort setting that can be turned off? I believe it acts as a pre-heat which will stop the boiler firing intermittantly
 
i had similar situation where there was not a bypass install and pump was winding it self up .......

r u sure u r hearing the fun running ??
 
Looks like a s plan with no bypass below boiler.

d2 safety relief in overflow pipe... Not to regulations. That would just melt if it discharged.

I would guess the boiler is not wired correctly, more likely an installer fault than a new vaillant boiler playing up already!? Don't be surprised if vaillant charge you for the call out!
 
Something not quite right? 37kw ? Is your cylinder 2100L? Who sized boiler you or installer? I'm sure if I was doing Job on a price you would have and 18kw or 24kw maximum! Think partial load could be set to 8kw on boiler but that's probably not the issue. Ask original installer to come back, then employ a competent and qualified installer? What was the company called who did the job for you?
 
Sorry I didn't realise there was a competition for most posts! What's the prize? Did read the whole tread, what I had intended to write was edited out almost entirely as I didn't want to seem rude and what was left was the rest. Who was / is walks with a limp. I shall endeavour not to post unless entirely unavoidable and no one has used any of the words or letters in a similar combination.
Suppose you would like a forum where automatic responses and one liners answer every question.... Not really a forum any more? Apologies if this matter was ever included in a previous post !
 
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Zebedy de gas said:
Sorry I didn't realise there was a competition for most posts! What's the prize? Did read the whole tread, what I had intended to write was edited out almost entirely as I didn't want to seem rude and what was left was the rest. Who was / is walks with a limp. I shall endeavour not to post unless entirely unavoidable and no one has used any of the words or letters in a similar combination.
Suppose you would like a forum where automatic responses and one liners answer every question.... Not really a forum any more? Apologies if this matter was ever included in a previous post !
Click to expand...
No, just seem a bit of a waste to repeat info to OP, I say it just seams a bit of a waste of time to keep repeating yourself, that is all. :cheesy:
 
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Can we get back to topic please. In my opinion, Something not quite right? 37kw ? Is your cylinder 2100L? Who sized boiler you or installer? I'm sure if I was doing Job on a price you would have and 18kw or 24kw maximum! Think partial load could be set to 8kw on boiler but that's probably not the issue. Ask original installer to come back, then employ a competent and qualified installer? What was the company called who did the job for you?
 
gassafe said:
Looks like a s plan with no bypass below boiler.

d2 safety relief in overflow pipe... Not to regulations. That would just melt if it discharged.

I would guess the boiler is not wired correctly, more likely an installer fault than a new vaillant boiler playing up already!? Don't be surprised if vaillant charge you for the call out!
Click to expand...

Thanks for all your responses it has been helpful, today had the engineer from vaillant to look at the issue, turns out the boiler is not wired properly, the timer is just opening the values as per the setting and not receiving/sending any signals to boiler to turn off or on. The boiler is always in demand mode hence starting every 20 mins once the temperature goes below the flow temperature set.

He also pointed out to replace the D2 safety relief pipe in plastic and check if the cylinder has internal expansion vessel for sure.
I read the manual for excelsior it says it has an internal expansion by providing a volume of air above the water level inside the cylinder and has an Air Gap Device that recharges the air gap when water is drawn this all sounds good but how can check if the fitter has fitted it properly?

The fitter is returning tomorrow to correct the issues, hope he does else would ask you guys again to suggest a plumber / installer to correct the issue.

Regards,
Santhosh
 
easy repair then on the wiring just boiler need SWL back from wiring centre ....
air bubble if isnt there you will be seen water dripping from discharge pipe
 
Hello Forum,
I had the installer comeback and correct the wiring, when the timer is in auto mode boiler turns on and off as per the settings in the timer. where as when the timer is in continuous mode the boiler always stays in demand mode (radiator icon displayed in the boiler display panel) boiler starts and shuts off atleast 8 - 10 times in an hour.

Spoke to vaillant they suggested to check the pressure in the boiler and bleed air from all the radiators and make an appointment if it continues the same, the builder came around this evening and increased the pressure to 1.2 bar and released air from all the radiators but that hasn't helped.

I feel wiring issue is not completely corrected, how ever he says he has followed what has been suggested in the boiler and timer manual. Don't want to call vaillant as if its wiring issue their engineer had already told that it will be charged next time unless it is corrected before the next visit. Do you guys feel it to be a wiring issue?

Many thanks,
 
Last edited by a moderator:
When u say starts and shuts off. Does it power off? Does the burner shut down ? Does the pump stop? Sounds like possibly flow reaching temp and boiler just modulating down? Possibly partial load too high?
 
Ermintrude said:
When u say starts and shuts off. Does it power off? Does the burner shut down ? Does the pump stop? Sounds like possibly flow reaching temp and boiler just modulating down? Possibly partial load too high?
Click to expand...

yes, the burner comes on when the boiler starts, stays on for about 2 mind and goes off then the timer icon is displayed and the heat sink fan will be on for 10 mins then boiler completely turns off after five mins starts again this repeats for ever.
 
Recovery time 3ms! Boiler well over sized. U needed 837 combi or perhaps a better solution would have been 24kw system boiler.
 
santhosh said:
before ordering this model I checked on vaillant site with my requirement and it suggested this model and also the fitter and builder had suggested this 🙁
Click to expand...


Of course it did. Maximising profits is the name of the corporate game.
Just look it up on the web and Bobs your mothers brother for all the answers :smile:
 
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I think the problem is that the installer has left the 24v rs link in the boiler
This needs to be taken out when using external controls hense why the boiler is on constantly on
the reason it keeps going on and off all the time is that the boiler is just pumping round a small circuit when the zone valves are shut then when it reaches 75 degrees will turn off eventually the boiler will overheat and u will have to keep re setting it
When the zone valves are open ie when on at the proggramer the boiler will work fine
Should be a simple fix really hope I explained this ok
 
Good shout Phil. Overlooked that one as it is mentioned somewhere (can't be bothered reading through it all) that vaillant came out¿
Btw i wonder why have they made the new links a bit bare silver wire you can (well i can't) hardly see instead of a nice bit bright red? Maybe to reap some call out cash??
 
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tamz said:
Good shout Phil. Overlooked that one as it is mentioned somewhere (can't be bothered reading through it all) that vaillant came out¿
Btw i wonder why have they made the new links a bit bare silver wire you can (well i can't) hardly see instead of a nice bit bright red? Maybe to reap some call out cash??
Click to expand...

Me think :
if the link was in the Vaillant engineer would have seen it !?
 
SafeGasInstall said:
Me think :
if the link was in the Vaillant engineer would have seen it !?
Click to expand...

Doesn't look like the vallient engineer has resolved the prob from the last post it still sounds like the boiler is constantly on to me that can only point to the live link being left in

Is the programmer opening and closing the zone valves ?
 
phil the bucket said:
Doesn't look like the vallient engineer has resolved the prob from the last post it still sounds like the boiler is constantly on to me that can only point to the live link being left in

Is the programmer opening and closing the zone valves ?
Click to expand...

Valiant engineer probably wouldn't have noticed! Had older one with f78 code - air bubble in pressure sensor... Valiant have a kit which lifts sensor up 5 mm custard paid for 3 parts service thing..... Got a pump expansion and something else!
 
phil the bucket said:
I think the problem is that the installer has left the 24v rs link in the boiler
This needs to be taken out when using external controls hense why the boiler is on constantly on
the reason it keeps going on and off all the time is that the boiler is just pumping round a small circuit when the zone valves are shut then when it reaches 75 degrees will turn off eventually the boiler will overheat and u will have to keep re setting it
When the zone valves are open ie when on at the proggramer the boiler will work fine
Should be a simple fix really hope I explained this ok
Click to expand...

Thanks Phil, when in auto mode the zone valves open and close as per the time no issues.
today the engineer from vaillant came around again, he said the thermostat temperature was more than the flow temperature in the boiler hence it was repeatedly turning on and off, then he changed the temperature in the boiler to 70 and set the thermostat temperature to 65 and said it should be fine now and left. He also reduced the load to 24KW from 36KW.
After these changes the boiler was on for 25 mins at one stretch to heat up the water in the cylinder after that it's starting once every 15 mins for 3 mins and shutting off. when it starts the burner comes on for 2-3 mins then the extractor fan with runs for 8 mins this continues so there is constant noise either burner or fan 🙁 will check with the installer if he has removed the 24v rs link as you suggested.

Regards,
 
tamz said:
There is a black going into RT.
Check external wiring and zone valves for sticking micro's
Click to expand...

My thought is there maybe a perminet live in RT as it's a new installation it needs checking by a competent person really
think this person is doing the work himself as croppie said be carefull
 
Guys,
I am not doing the work myself, the issue is because my builder has used a useless guy for installation and its been a struggle with him to get some one to fix it 🙁

20131002_072128.jpg

20131002_072033.jpg
 
Last edited by a moderator:
Get somebody in ASAP to sort this mess out can't really help u out anymore than that my friend
 
based on the last few comments above I'm now closing this thread - with quite a bit of relief!

Please go to Gas Safe Register | Ensure your gas engineer is registered. or post a thread in the 'I'm looking for a plumber / gas engineer' section of these forums remembering to include your location. [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]
 
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