Valiant Eco tec 3 yr old install dilemma

[matz]

We had a new valiant eco tec non combi fitted by a pro firm 3 yrs ago (existing CH system is approx 30 yrs old) , system was power flushed by installer according to their invoice and fitted with magnaclean.


Boiler has never worked 100% ie keeps cycling due to (according to subsequent heating engineer) circuit obstruction. Cycling in our case = boiler temp climbs fast and clicks off so CH water never gets really hot - sorry I may not have right terminology here.


Valiant have replaced HE free of charge under warranty. Its still cycling.


Since then I’ve had all downstairs rads off walls and mains flushed them through in the garden also flushed through all downstairs rad feeds from upstairs until water is clear - lots of black filth came out. I had 2 microbore rad elbows blocked with rust during this.


Boiler still cycles and a further engineer says the new HE is part blocked ( 6 months old)


We have a 20 yr old copper DHW cylinder ( engineer has said it may be part blocked) and gravity fed showers with feeble flow, also CH downstairs is 8mm microbore, upstairs is 15mm pipe. According to some people, Valiant HE has very narrow pipework that clogs easily and the boiler is not suited to any system unless that system is in mint condition plus microbore pipe is not doing it any favours.


Diverter valve for CH and DHW has never worked properly in 12 yrs and despite 2 new pro fitted valves doesnt work to this day so DHW via boiler doesnt work 100% and we use immersion 24 hrs.


I’m thinking of cutting my losses, installing a combi and chucking the 3 yr old Valiant boiler away as I can then choose a boiler that is more suited to an old system, I can install showers easily that have good flow and I can do away with the copper cyl.


I should have had a combi in the first place.....I should have called original firm back again but didnt at the time (due to various reasons) and now its too late to do so...


I’m baulking at doing this due to paying £2k 3 yrs ago and prospect of another £2K for a new combi now.


Any observations, suggestions or advice welcomed re. the above dilemma.....

 

[simond]

You don't say which ecoTEC? Is it a 4 series or 6 series?

If the system was originally open vent (small header tank in the loft) or still is (4 series then) then there's a reasonable chance there's an obstruction where the cold feed and open vent are/were cut into the pipework.

Powerflushing and Magnets won't help here.

A new heat exchanger wouldn't block immediately so if I've read your post correctly that isn't the primary issue.

Haven't had an overflow running too, by any chance?

 

[matz]

Simond, thanks for your reply. Its a 415 and yes theres a header tank in loft. No overflow happening...

where would the obstruction be exactly?

digressing slightly, should I be considering this? http://vaillantcyclingproblem.blogspot.co.uk/p/problem.html

 

[simond]

You've got weather compensation? That's different - but few 4 series were fitted with it.

The obstruction will normally be where the cold feed from the tank enters the central heating pipework. This should be just before the pump, which is separate in a 4 series.

 

[matz]

You've got weather compensation? That's different - but few 4 series were fitted with it.

The obstruction will normally be where the cold feed from the tank enters the central heating pipework. This should be just before the pump, which is separate in a 4 series.

re. weather compensation ok, prob not applicable to ours then but I'll take a look at the pipework in area you mention.

 

[picasso]

Was the pump replaced when your new boiler was fitted ? press the I button on the front of the boier the next time its cuts off and see if S56 is showing on the display.

 

[matz]

I put a new pump on last year just in case that had anything to do with it but didnt make any difference. We will put heating on this morning for first time since the spring. Hot water has been on immersion all through the summer.

 

[matz]

well, boiler was switched on 9am this morning from cold on CH only and its been continuously for 1 hr 15mins perfectly ie not noise, not cutting out. Boiler temp gradually rising, rads getting hot, room stat up to 18. Right now (after 75mins) the boiler starts kettling noises as temp approaches 70 and then shuts off, temp drops back then boiler fires up again etc. Feeling the flow and return pipes at top of boiler, one is red hot ( cant touch it) the other is hot (can place hand on it) Rads are hot but not piping hot. "i" button on boiler when pressed after boiler shuts off shows 5.2.

 

[matz]

You've got weather compensation? That's different - but few 4 series were fitted with it.

The obstruction will normally be where the cold feed from the tank enters the central heating pipework. This should be just before the pump, which is separate in a 4 series.

regards this, theres a 15mm copper pipe running from header tank in loft to area below pump in airing cupboard teeing into one of the pipes flow or return pipes coming from the copper cylinder. The header tanks water is very very dirty brown and is quite warm. No idea whether any of this is significant!

 

[tartangasman]

Sounds like ur system is pumping over. Water in header should not be hot.
U must have blocked or at least partially blocked pipe work . Probably near
Where cold feed pipe enters system

 

[matz]

Sounds like ur system is pumping over. Water in header should not be hot.
U must have blocked or at least partially blocked pipe work . Probably near
Where cold feed pipe enters system

have been running it on and off all day and have spent over an hour bleeding the system as there seems alot of air in it also in the magnaclean. The water in the header tank is cold tonight but was warm this morning after running for an hour. I've checked the cold feed from header tank to just below pump in airing cupboard which is 15mm. It comes out of the tank in the loft pointing down for about 30" at an angle then a bend and a 40" horizontal run then straight down into airing cupboard. I've had the header tank empty today and cleaned out, the water runs away ok and theres good suction when you put finger over tank outlet. I cant quite see where any obstruction would be...

On a more positive note, due to extensive bleeding, the boiler actually seems now to hold its temperature at around 75, the rads are getting good heat but the boiler is roaring away loudly at this level but at least its not cycling.... at the moment!

edit
when I say lots of bleeding, I undid bleed screw on the magnaclean approx 7 or 8 times over period of one hour and each time some air came out. - this was in addition to bleeding rads and the vent pipe in the airing cupboard (vertical pipe with valve on top)

 

[Agile]

By your own admission there has been and still is a lot of dirt in your system.

But nowhere have you said when you empty the magnaclean or what is in it.

Why not spend your money replacing 8 mm pipes with 15 mm and properly cleaning the system?

What about your auto bypass?

Tony

 

[Agile]

Boiler still cycles and a further engineer says the new HE is part blocked ( 6 months old)

You talk as if you think the boiler should not block in 6 months.

Well its YOUR dirt and not Vaillant's dirt.

You have a magnaclean but have not said anything about cleaning it.

Tony

 

[matz]

the systems been in 3 yrs, it was the installers responsibility to get it right. If it wasnt suited to microbore they should have told me. I paid the money and have a faulty system/ boiler or whatever. The magnacleans been in 3 years ie from the date of install , do you really think it hasnt been cleaned out just because I havnt said it has been?????

 

[matz]

Why not spend your money replacing 8 mm pipes with 15 mm and properly cleaning the system?



Tony

how much more can I do then employ an installer to do this job which to maintain makers warranty means they need to flush/ clean the system inn order to prevent the very thing that has happened. In addition to this anyway and later on, I have cleaned out all the pipes as described on this thread and the upstairs of the house is 15mm anyway. What else could I have done???