What's wrong with my Vaillant Ecotec Plus boiler?

[gas4you]

I assume it is a 2 port valve then and it will have a 22mm pipe at each end.

Also assuming this, you will have another one in there as well (or at least you should have) that controls the heating.

In this case you MUST have an auto by-pass fitted.

I am starting to get a few alarm bells about your installer, the further we delve into your installation

 

[David937]

Thank you for your time Dave.

 

[MaryJane7]

Ok, I've taken a deep breath and been in the airing cupboard again and 'yes' you're right, now I can see that there are 3 22mm pipes connected to the box which has written on it Honeywell 'power head for motor valve' (one to the hot water tank, one to the central heating and one from the pump). Sorry.

 

[gas4you]

Right, you do not need a bypass then, but there must be a circulation problem on the heating side.

Was the system properly flushed and the expansion tank fully cleaned out?

As it works for HW, I do not think it is a boiler problem

 

[MaryJane7]

Thanks for letting me know that I don't need a bypass.

My invoice states that the system was power flushed last February when the new boiler was fitted. Unfortunately I wasn't here when this happened so can only assume that my installer did what he said he would do.

In mid-December, on Valliant's instructions, the installer drained down the system and cleaned out the expansion tank prior to the new HE being fitted.

What else can I do if its a circulation problem?

Thanks for talking to me!

Mary Jane

 

[gas4you]

Have the boiler ntc's been checked that they are fitted in the correct positions?

Strangely, the only boilers that I have had this problem on have been the 400 series

Just because your system has been flushed doesn't mean it is clean.

One 400 I fitted I powerflushed the system until everything ran clean trhough it, even had all new rads fitted.

6 months later the HE blocked

Fitted new HE and powerflushed again. I was totally shocked to get as much muck out as the first time. God only knows where it came from, I certainly didn't

3 months on and system failed again. This time the pump had seized solid due to muck in the system again. Fitted new pump, flushed and also fitted a spirovent dirt collector.

So far, fingers crossed, i have not been called back since. (I hope I have not talked it up )

I fear that yours is going to be a problem that will only be resolved by whoever is on site!

 

[MaryJane7]

Oh dear Dave your story about muck in the central heating system (even after power cleaning) is a bit depressing. Gulp. (Your emoticons helped slightly!).

Please can you let me know what it means when you ask 'have the boiler ntc's been checked that they are fitted in the correct positions?'. Fraid I'm stuck on that one!

Do you think that it would be a good idea for me to get spirovent+magnetic dirt collector fitted? I saw something like that advertised on the web.

Meanwhile my installer has agreed to pop round tomorrow. I'll let you know what happens ....

Cheers and thanks, Mary Jane

 

[Agile]

Although I would fit an auto bypass to a two port system, the Vaillant manual does say that an external bypass is NOT required on those boilers which have an internal bypass.!

In your case, its been pointed out that the heat only model does NOT have the INTERNAL bypass just left of the pump as I described in my earlier posting.

As you have now confirmed that you have a three port valve an auto bypass is not essential as long as an adequate minimum flow rate can be still achieved when all the TRVs are off.

It still seems odd to me that when the integral bypass is a standard component of the system and combi models, its left out of the heat only when its such a small and cheap part.

Tony

 

[mickyg]

In your case, the boiler should have an INTERNAL bypass as I described in my earlier posting.

In your case your completely misleading the OP. This is a 400 heat only boiler. There is no internal bypass.

 

[mickyg]

To the OP, where is the boiler situated in relation to the airing cupboard and the header tank?

 

[Agile]

Right then forget that! To avoid any confusion I will edit that suggestion out.

In that case as Dave says you must have an external auto bypass fitted.

As another experiment, if you open the mostly closed TRVs to the living space positions or higher then I would expect the S53 to either cease or considerably reduce.

Tony

 

[MaryJane7]

Thanks to Agile and mickyg for their postings.

Didn't Dave say that I didn't need an external auto bypass because my system's got a 3 port valve, or am I getting confused?

The airing cupboard is upstairs on the landing. The header tank is directly above it in the loft. The boiler is downstairs in the kitchen about 2.5 metres off the vertical between the airing cupboard and the header tank. Hope that's clear.

Some time ago I tried opening all the rads to maximum, but still got the S.53 error at both cold start and warm start. However I haven't tried this experiment with my new d0 setting of 8 rather than the original setting of 18. Will try this tomorrow. Thanks.

Mary Jane

 

[Kev F]

Thanks for the recent postings - I'll now try and answer any queries raised!

The boiler is a Vaillant Ecotec418

I followed Agile's instructions on how to find out the boilers maximum heat output (d0 setting) and found out that the value is already set at 18

Yes, Dave, it was the main HE that the Vaillant engineer replaced

As this is my first ever forum, I hadn't realised the importance of the 'location' box so I just put my birth county. Sorry. In actual fact I now live in Cambridgeshire, and the Vaillant engineer came from Peterborough. Hope that's cleared that one up!

i live in cambridgeshire and have net 3 vaillant engineers, 2 from peterborough, 1 doesnt go into lofts

 

[Agile]

If you have a three port valve then you dont need an auto bypass as long as there is sufficient flow when all the TRVs are closed.

However, depending on the flow rate through the "always on" radiator, then an auto bypass might still help to avoid the S53.

It may help to see if its possible to open the lockshield or control valve on that radiator in an effort to increase the flow rate through the boiler and reduce the incidence of S53. Perhaps at least 2½ turns open but that may upset the balance of the rads. Hopefully they have been balanced?

Tony

 

[stardanny]

Hi.

I have been reading and thinking, but I may be wrong:
The hot water work okay cos it has 22mm flow all the way to cylinder via pump and valve from boiler and 22mm return from cylinder to boiler, so the boiler working as it should.
From cold start, Mary say the heating work ok IF the hot water calling for heat at the same time as heating, ( at default setting on boiler ) and when the hot water stop calling for heat, valve close to hot side pipe, giving way to heating, as the heating heat up, the TRV start closing leaving lounge rad open, reducing the flow rate of pump, causing the diff of flow and return temp? A bypass is missing?

But I don't get it, after reading this, she open all TRV and still it give error state ( not default setting on boiler).

As you have not use the heating since installed in Feb, the first time you switch on heating, it give you problem, I would think it the installion fault, something that affect heating flow?

Just need more info, when you had the boiler replaced, was the pump and honeywell valve replaced? Is there a autobypass fitted ( somewhere in airing cupboard, between pipe after the pump and onto cylinder return pipe?

Dan.