Valiant Eco tec 3 yr old install dilemma

[Agile]

I don't think the installers properly cleaned the system.

How many days did they take to install the boiler?

I am still surprised that your system has so much dirt if you are cleaning the magnaclean every week or two.

Do you know what chemicals were used by the installers? And since then?

We still think its sometimes pumping over, thats why its hot. See the FAQ for how to leave a test on it.

Tony

 

[oph]

Distribution pipeworks too small and its cooked the HX

 

[Agile]

Probably has no ABV too.

 

[oph]

Probably has no ABV too.

only required on S Plan anyway unless Vaillant specify it regardless

 

[matz]

I don't think the installers properly cleaned the system.

How many days did they take to install the boiler?

I am still surprised that your system has so much dirt if you are cleaning the magnaclean every week or two.

Do you know what chemicals were used by the installers? And since then?

We still think its sometimes pumping over, thats why its hot. See the FAQ for how to leave a test on it.

Tony

no I dont think so either!

2 of them were there over 2 days but tbh my memory of it all is getting hazy now

I'm not cleaning the magnaclean every week or two. I cleaned it quickly after install and kept checking it every few weeks. Its cleaned out every service. I cleaned it out alot when I did the flushing work to ensure it was not attracting too much dirt. last check I think was couple of months ago when it had about 5mm of silt on it.

dont know what the installers used to flush it. They put inhibitor in it before they left. When I had the aggro with it all later, I put the flushing stuff in it on advice of Valiant and left it in for 2 weeks then inhibitor again

re. pumping over, I have just checked the loft and the tank is warm. I've looked at the FAQ (interesting link) and will double check with a magnet etc for crud.

Its the pumping over bit I dont understand - how does it doing this affect the way the boiler runs?

re. the boiler its settled down somewhat now - makes a racket when first starting in the morning then seems to settle down. rads seem hotter than after the install

 

[simond]

Boiler making a racket is normal when air is drawn in, because pump is not working efficiently when air is in it. Air being drawn in is another facet of the pumping over problem.

If the header tank is pumping over, it is perfectly feasible that the system has become corrupted by sludge since the Vaillant was installed. If this is the case, your Magnaclean will be full of muck.

The Vaillant heat exchanger has a high flow resistance, which makes it particularly sensitive to water flow rates round the system, I'm not sure I would have specified it for a microbore system, as that, of course, gives a large pressure drop in itself.

The original boiler would have had, most probably, a cast iron heat exchanger with minimal pressure drop. This is relevant because the greater the pressure drop across the boiler the more critical the positioning of the 'open vent and cold feed' entry to the system to prevent the pumping over.

In other words, whatever the CF and OV layout format existed when the original boiler was taken out - it should have been altered to comply with industry practice/Vaillant recommendations when the new boiler was installed - or trouble of the very type you describe will ensue. We've lost plenty of jobs by insisting that we cost for the pipework to be altered, only for another installer to inform the customer it will be alright without the 'unnecessary' work.

Many customers hear the last bit but not the first bit, because they want it to be cheaper.

 

[gigz]

Don't even consider putting a combi on a durty system. You'll be forever changing plate heat ecchangers.

 

[matz]

thanks for all this further input,. I'm stuffed really as I should have got original installer back in and now its too late. 2nd installer told me the valiant was not suitable for microbore. Irony is my install was one selected for a gas safe inspect but I guess thats for gas matters only..I will pay some attention now to the pumping aspect...

 

[gigz]

Seen loads of vaillants on microbore systems. Is it balanced properly ? Unusual to have 8mm down and 15mm up mind (usually larger bore pipes down lower)

 

[gigz]

Re the 2 port valves, have you tried manually opening the HW one and keeping it open see if it works ?

 

[matz]

Seen loads of vaillants on microbore systems. Is it balanced properly ? Unusual to have 8mm down and 15mm up mind (usually larger bore pipes down lower)

unsure about balancing sorry but all rads are heating up. Layout was put in when house new and now approx 25 yrs old. I did think about changing microbore for 15mm but couldnt face it! Its dot and dab downstairs but gap is very narrow and I dont want surface pipework

 

[matz]

Re the 2 port valves, have you tried manually opening the HW one and keeping it open see if it works ?

sorry gigz, you're losing me now! what and where is the 2 port valve?

 

[gigz]

Re the 2 port valves, have you tried manually opening the HW one and keeping it open see if it works ?

sorry gigz, you're losing me now! what and where is the 2 port valve?

It could be a three port ? Its the valve(s) you mentioned in your op. HW/heating diverter valve. B port goes to the cylinder and A goes to the rads. You might have a bypass that needs setting as well.

 

[matz]

Re the 2 port valves, have you tried manually opening the HW one and keeping it open see if it works ?

sorry gigz, you're losing me now! what and where is the 2 port valve?

It could be a three port ? Its the valve(s) you mentioned in your op. HW/heating diverter valve. B port goes to the cylinder and A goes to the rads. You might have a bypass that needs setting as well.

ah right yes the diverter valve.... the programmer is set to continuous CH with DHW off so I presume diverter valve is setting itself to CH only, as the rads are heating up. The tank is on immersion but I cant recall whether I tested that the tank was being heated by the boiler with diverter as set by programmer, I just assumed not.

 

[Agile]

You need to put a bag or condom over the vent pipe to see if its pumping over.

Depth cold in F&E tank?

Distance between vent pipe and water cold?

Tony