Vaillant EcoMax wiring

[Samlinbolo]

Hoping for some advice. Moved into a new house October 2014 with Vaillant EcoMax installed 2006. Boiler seemed fine, had been serviced May 2014 by installer. In summer just about to arrange for a service with gas safe plumber I had used previously for servicing W-B combi in previous property (service had come due but also boiler starting to sound a bit noisier than had previously) when we had to turn off boiler completely in order to have our electricity meter replaced. On turning it back on it was completely dead. Called engineer who thought perhaps electrical switch simply needed replaced. Did that but boiler still dead. He thought it must be the PCB. He explained that he would order both PCBs as couldn't be sure which one was needed. Replaced both and boiler working again but it still sounded very loud and I was concerned. He thought it was probably the fan (and that perhaps that has triggered the problem with the PCB) so he replaced that. The boiler sounded okay although still a bit noisier than I expected but thought it was perhaps as I was used to a much newer combi. Recently I became concerned that the cold water tank in the loft seemed to be constantly refilling/topping up. I could hear a lot of noise from the water flowing into it. Also boiler was becoming increasingly loud and unhealthy sounding. Called a different engineer who came yesterday. He said that the boiler was wired incorrectly. The pump is not wired directly into the boiler. Also there is no thermostat on the hot water cylinder. He explained that this would be preventing the pump from cooling down properly and explained issues with cold water tank. He said the water up there would be warm if I put my hand in. He also asked if our hot water is very hot. It is scalding despite us having the heating on only twice a day and room thermostat low! Another problem we weren't sure how to fix. He said it need a complete rewire (about a days work) and a thermostat fitted to HW tank plus possibly a filter as it sounds as though some of the noise is from kettling/debris. Just wondered if someone could advise if this all sounds right. I have checked his gas safe reg and he is Vaillant accredited. Just feeling worried after previous plumber didn't noticed any of this. Thanks for your help.

 

[simond]

And the Vaillant ecoMAX model number is?

 

[Samlinbolo]

Thanks for your reply. It is an EcoMax Pro 18e.

 

[simond]

This is a basic Saunier Duval boiler rebadged as a Vaillant.

By your description, the boiler has been installed in 'open vent' configuration, with a header tank in the loft, probably around the size of a WC cistern.

Open vent boilers have to be connected carefully, particularly modern condensers with high resistance heat exchangers. Many heating installers do not understand this (I'm sounding like Agile here, where's my tablets?) and end up fitting a new boiler in a pipe layout that is doomed to fail.

It is pumping over, which means water is being evaporated and entraining air, causing massive corrosion in the heating system. The boiler will almost certainly be suffering from sludge contamination, leading to poor performance and noise issues.

Whilst the cause can be resolved, your boiler may not ever be the same, as the heat exchanger cannot easily be cleaned out. But then that model was always a bit rough, so arguably not a big loss.

As a minimum you will need to have the pipe layout changed to stop pumping over, or change to a sealed system with no F&E tank. You will need a full powerflush, but if this has been left for long the boiler is probably not in good shape.

So no good news really. You need to get someone with a bit of knowledge looking at this, not some chancer. You may well have wiring issues; problem installs tend to have multiple defects, if they can't be bothered to learn how to pipe it up, they are not going to do the wiring justice either.

The wiring is just the thin end of the wedge however.

 

[Samlinbolo]

Thanks for explaining all that. It is bad news but better to know it than not know it. The guy who looked at it thought that once rewired and filter fitted it would be a good system but I had the same worry that you have explained about the effects of ten years of corrosion and sludge. I had a look in the feed and expansion tank and it is very sludgey.

 

[ScottishGasMan]

He's right in it needs wiring correctly. Another issue is that with that many year with the pump not wired correctly the heat exchanger coils are very possibly damaged and contributing to the noise, as everytime its switched off essentially you are roasting the heat exchanger as the pump goes off and does not dissipate the leftover heat.

So Wiring def needs done to standard. By the sound of it flushing and some repiping to prevent future pumping over. (by the way a filter on its own will be nigh on usless in helping a system suffering from pumping over as the massive amounts of air in the water cause a different type of corrosion from your typical magnatite, this red/orange sludge particale are not attracted to magnetic filters nearly as readily as magnatite.

So, Wiring, Some Pipework configuration, Full Flush - clean out F+E, fit filter for future, and you still may have noise issues if the Heat Exchanger is away.

At this point the boiler should work well, and could continue to for a long time (although noisely) with the expense of all that, I would think it would be worth replacing the boiler at the same time (heat exchanger costs quite a lot of money) and then you have the system sorted out, and a new boiler with a warranty that could mean no repair bills for some years to come, as long as the above work is done correctly and its continually serviced.

 

[Samlinbolo]

Thanks for your advice, that is all very helpful. I could tell the system just wasn't right despite all the replacement of parts in the summer and now I understand why. At least we can get it properly sorted out now. Thanks again.