What's wrong with my Vaillant Ecotec Plus boiler?

[Deleted member 105431]

Is the pump wired directly to the boiler pcb or is it wired into the orange of the 3port?

If wired incorrect this could be the cause of the problem.

 

[gas4you]

Tony, it has already been established that Mary Jane has had the fault even with all the rads set to fully open.

 

[MaryJane7]

Thanks for your really helpful recap Tony. Think I'm beginning to get the hang of all this!

I've now been to have another look at the living room radiator. The lockshield was already fully open, I can't turn it any more anticlockwise. So I then turned it clockwise to see how many turns it takes to fully close. The answer is 1.75 turns. I've now turned it 1.75 turns anticlockwise again so that the lockshield is fully open again.

The control valve on the other end is open. I checked that with my installer yesterday.

Hope this is helpful.

Mary Jane

 

[MaryJane7]

dangermouse, there's a white wire going from the pump towards the boiler and a black wire going from the 3 port towards the boiler. There doesn't seem to be a direct linking wire from the pump to the 3 port.

 

[gas4you]

dangermouse, there's a white wire going from the pump towards the boiler and a black wire going from the 3 port towards the boiler. There doesn't seem to be a direct linking wire from the pump to the 3 port.

There probably would not appear to be, as all the flex would be linked to their respective connections in a wiring center.

 

[Agile]

OK thanks.

There really does seem to be a serious lack of flow in the heating circuit.

A possible further indicator would be to start the heating from cold and feel the flow and return pipes at the boiler and time the delay before the return pipe starts to get warm.

That should not be more than about 2-3 minutes before it starts to be fairly warm.

Thats using your hands to get a simple indication.

Of course the boiler will display the return temperature in d 41 but there is always a possibility that this is not exactly reflecting the real temperature. On site I would be using my contact thermometer to independently check the flow and return temperatures.

One wonders if the installer has done the bucket test on each of the pump valves! Most installers has encountered one pump valve with a serious blockage at the restriction or in the pump volute.

Tony

 

[MaryJane7]

Thanks for your postings Dave and Tony. Thought it might be helpful to do a recap on how things have progressed so far.

Before I joined this forum, my central heating boiler always came up with the S53 error code immediately on starting, whether from a cold or a warm start. During the last week I've taken your advice and have (a) reduced the power of the boiler from 18 to 8 Kwatts (b) increased the pump over run time from 5 to 10 minutes (c) increased the pump speed to 3.

The central heating now seems to work (no S53 error) from cold start up and, from my observations over the last couple of days, usually seems to work from warm start up (I've noticed one S53 when the room thermostat tried to turn on the boiler after it had been off for a shortish time). A return to d0=18 immediately means a return to S53.

I tried Tony's test this afternoon when the heating had been off for 3 hours. The return pipe started to feel luke warm in 4 mins, warm in 6 mins and fairly hot in 10 mins(when d40=51 and d41=34). I then thought I'd continue to monitor d40, d41 and the status of the boiler incase it was useful. This is what I got (the times given are all taken from initial start up):

after 12 mins, d40=55, d41=38, S4
after 17 mins, d40=60, d41=43, S4
after 20 mins, S7 replaced S4, d40 dropped to 47, d1=46, and after a bit (forgot to time that!) S30 displayed

about half an hour later, the boiler started up again automatically from d40=39, d41=39; and both temperatures increased so that if d40 raced ahead of d41 and the differential became greater than 20 then d40 came down a couple of degrees and waited for d41 to increase before carrying on.

This looked really good to me. What do you think? Not sure about that S53 on warm start up earlier in the day though.

Do you still think the system has really got a physical blockage and we've just done a 'work around', and if so does the blockage still need to be found and removed?

Any more ideas gratefully received! Thanks for all your help, Mary Jane

 

[Agile]

Thanks for that Jane.

Clearly we have certainly managed to get the system to work far better than before by a little readjustment of the operating parameters.

I would think that they are pretty good and possibly with a slightly fussy boiler and a rather small system which has a limited warm heat demand possibly its the best we are going to get.

Its a little difficult for me to make any judgement about the flow rate through the system. It still seems a little slow.

However, lets see what Dave and any others have to say about that.

Tony

 

[MaryJane7]

Thanks Tony. Do hope Dave and others have time to respond to your comments.

Dave told me on an earlier posting (last Friday evening, 9.02pm) that on a similar boiler with the S53 error he had to powerflush (and other things) three times over 9 months before all was sorted. But perhaps that household had other problems as both the HE and the pump had to be replaced as well?

Meanwhile, what should I do about my installer's plan? Do you think that it is a good idea to go along with his idea to put in de-scaler? And then (gulp, gulp) what do you think about his final strategy of checking/ replacing all my central heating pipes?

I really appreciate all this help. This morning (cold start) the central heating system again worked well with d0=8 kWatts, but I couldn't check the warm start up situation as I had to go out. Will continue my checks later today.

Thanks again, Mary Jane

 

[gas4you]

Your readings seem to be constantly on the edge of what the boiler will accept electronically.

Some may say it is the perfect 20C temp difference, but the 400 series does not like this for some reason.

I personally would rather see a maximum of about 15C temp difference on this boiler and the only way I feel this can be achieved is by somehow getting the flow faster.

Perhaps your installer could also try a 15-60 pump as an experiment

My tale of wo was just an example of how even when things are apparently done correct, there will always be the 'rogue' system out there that causes a problem.

Has the system been powerflushed properly with a power flush machine? I can't remember now.

I wouldn't worry too much at the present time about replacing all the pipe work, especially as it is small bore.

If he is going to fit a 'de-scaler' as you call it, I would suggest the new Spirovent with the magnet fitted.

 

[MaryJane7]

Thanks for your posting Dave. I do see what you mean about trying to get the flow faster to try and reduce the temperature difference.

Is a 15-60 pump more powerful and so might get the flow going faster? I've had a look at the present pump and its a grundfos 15-50, so I could certainly ask my installer to try a 15-60. Sounds like a good idea.

Oh, bye the way, the pipes are 15mm.

I asked my installer last Saturday whether he had powerflushed the system before fitting the new boiler last February and he said that he did do this.

Sorry that I wasn't clear about putting in descaler, I actually meant that the installer has said that he'll put in a descaling liquid (like I ocassionally use in my kettle I suppose), leave it in the system for a week and then drain and flush. Does that seem a reasonable thing to do? I was just a bit concerned that this will dislodge bits of old limescale in the pipes and they'll travel round into the boiler and block the HE? Or perhaps that's being paranoid?!

Meanwhile, I'll get on the web to look up the new Spirovent which you've suggested.

Many thanks for your help, Mary Jane

 

[Kev F]

for all the time everyone has spent o n this and the time the installer has been there think i would of put 2x 2 port valves in by now, a magna clean and given it a powerflush

 

[Deleted member 105431]

as i said earlier I would fit a robokit to convert to sealed system and fit a 15/60 and magnaclean/spirovent dirt sep.

 

[Agile]

I asked my installer last Saturday whether he had powerflushed the system before fitting the new boiler last February and he said that he did do this.

Many thanks for your help, Mary Jane

He says that he did but you dont seem to have any evidence that he did.

Perhaps he did not?

Fitting the 15-60 will give a marginal improvement but there still seems to be a much lower flow than any of us would expect!

Tony

 

[MaryJane7]

Thanks to Eaton, dangermouse and Tony for their postings.

At the risk of starting to bore everyone on this topic please can I report back that I'm still getting S53 on warm (but not cold) start ups.

Reading eaton's and Tony's comments, should I ask my installer to do a powerflush (or indeed another powerflush) before he puts in the chemical descaler?

'Fraid I'm lost when it comes to putting in 2x2 port valves, Eaton. Presumably that's instead of the 3 port valve? And I'm also lost when it comes to rebokits and sealed systems, dangermouse. Sorry. Please can someone comment on those ideas?

Finally I've found the Spirotech web site and in particular their 'new SpiroCombi Magnabooster' which I think Dave suggested, as well as eaton and Tony. Think that's the one to ask the installer to fit?

Cheers, Mary Jane