Boiler gone again

[tjw1701]

I thought I would revive this post to update what has happened since, and it aint good

During the summer not that long after the boiler was fixed, I noticed the tank was overflowing (albeit very slowly). Upon investigation I found a tiny pinhole in the dhw coil, right below where the heated boiler water enters.

Albion technical where less helpful than a chocolate teapot (at least you could eat that) saying, tough mate tanks knackered you need a new one. Stuff that I thought, so set about plugging the hole with solder, and to my amazement to this day it is holding.

However the story unfortunately does not end there. A couple of weeks ago the cold forced me to relent and put the heating on, I so wish I hadent. Within about 15 minutes, no less than 3 radiators sprung a leak, one of which flooded my daughters bedroom and ruined the lounge ceiling.

I have had my pro plumber round, he reckons I should ditch the thermal store, fit an unvented tank and if the pipework will take it a sealed system, and if not a feed expantion tank in the loft. He thinks the water in the system is getting oxygenated either by a leak in the system or from the feed from the boiler dragging air in at the top of the tank (it comes in about 5-6 inches from the top of the water level). Ironically I flushed it thoroughly in July, and added 4 bottles of fernox which would give a concentration of 5-6%

Frankly I just want the thing sorted, I have now lost 5 radiators, 1 towel rail and two boiler exchangers which is rediculous, but somehow I dont want to give up on the thermal store system, when it works correctly it is fantastic, and I cant beleive my plmbing and the design of the store is so bad that so many rads etc have popped. (And of course I want to be sure it wont happen even with a new system).

Sorry this is such a long post, but I am so fed up with the whole thing I could really use some helpful opinions.

Many thanks!

 

[Agile]

Hi,

I have a Worcester Bosh 24ri boiler which is connected to an Albion 210litre direct thermal store. They were both fitted around 5 years ago, and today I had to have my second heat exchanger fitted to the boiler, so I am getting through them at a rate of 1 every 2 and a half years.....pricey.

Many thanks.

Which heat exchanger was replaced?

Exactly how had it failed?

tony

 

[tjw1701]

The main one in the boiler, it looks a bit like a kebab

The first one was corroded and had split with white stuff coming out the solit, the second one fitted in June was also corroded and split with white stuff, but didnt look as bad on the inside (at least what I could see through the in,et hole). In both cases however the boiler was banging away like an old kettle and kept switching itself off.

It has been fine since, but who knows for how long.

 

[Agile]

Who paid?

How old was boiler at each failure time?

Did you have any boiler cover?

Worcester say that failure mode is as a result of dirt which expands the outer casing where it passes the ribs inside.

They will carry on working even when significantly distorted though.

Why has your system been so dirty?

Many here would say its dirty because of the thermal store which are colloquially called "sludge buckets" here.

Tony

 

[tjw1701]

I paid, both times.

The boiler was roughly 3 and 5 respectively.

No boiler cover unfortunately.

Failure description sounds about right, although there is not normally much sludge in the bottom of the tank when I drain it, there is often grit like material though (probably the remains of my rads)

It did work if you put it on a very low setting, but put the power uo at all and it just went nuts banging and crashing, so suspect the water wasnt moving through it quicly enough.

As to why it is dirty, thats the million dollar question. Whenever a rad is removed the water in it is all brown suggesting rust, which would explain the pinholing. What doesnt make sense is why it keeps happening. In july I flushed the whole system out, and the water was clean, I put in 5-6% fernox (which is more than the recommended minimum) and still the rads churn out brown water.

The whole thing is only 6-7 years old.

I have seen they are known as sludge buckets, but this amount of failures seems a little excessive, if this is inherent of thermal stores I cant beleive anyone would go anywhere near them. If I change to a unvented I want to be sure I am not gong to end up in the same boat.

Thanks.

 

[twgas]

As to why it is dirty, thats the million dollar question. Whenever a rad is removed the water in it is all brown suggesting rust, which would explain the pinholing. What doesnt make sense is why it keeps happening. In july I flushed the whole system out, and the water was clean, I put in 5-6% fernox (which is more than the recommended minimum) and still the rads churn out brown water.

this doesnt make things clear. I'd like to know how the rads have dirty water but you say the system water is clean!!!!!

 

[DP]

What is the size of the header tank. Could you measure and post please. Also the depth of water and the distance between the overflow and top of water. Have seen this issue before

 

[tjw1701]

TWgas. Your right it doesnt make a lot of sense. If a sample was taken from the top of the tank, or the drain plug on the boiler the water appears quite clean, however when the popped rads were removed the water that came out of those was very brown and conatined lots of solid particles that looked like rust. This is a mere four months after I flushed the system and reloaded it with fernox. There is still a strong smell of fernox.

Dp. The thermal store is effectively the header tank, it has a removable lid, and in the top is (or was) a ball valve floating on top of 210 litres of hot water. The inlet from the boiler is about 6 inches below the overflow, and the water level is about 1 inch below the overflow. I had to remove the ball valve as this too got a pinhole, and filled with water rendeing it useless. I now manually top up the tank if needed, which since june it has not been.

Hope that makes a little more sense.

Thanks.

 

[Agile]

Something is wrong!

There must be a pumping over effect to cause the water to pick up oxygen somehow.

Tony

 

[DP]

I suspect you have a Boilermate in your property.

Does the overflow discharge at any time?

Isolate the cold feed to the header section and check if header loses water

Suspect one inch gap should be greater. You do not need that much water in the header tank

 

[Agile]

Based on those measurements the boiler connection is only five inches below the water level.

That sounds way to small a distance and sounds wrong.

I would expect all boiler connections to be within the main body of the tank and not in the header section!

Tony

 

[DP]

Tony is it is the Gledhill Boilermate, then that is the way it is configured with no components connections within the header tank installer alterable.

 

[tjw1701]

Hi All,

Thank you for your replies. The thermal store is an albion mainsflow contractor 210litre. There is no header tank in the traditional sense, the actual store is the header tank. Its about 1.7 meters tall, with a metal lid. Water fills the tank, which in turn directly connected fills the boiler and central heating circuits. The boiler connector sucks water from the bottom of the tank and pumps it back in heated about 5" below the surface of the water in the tank.

If it will make it easier I will knock up a little drawing and post that.

Thanks.

 

[tjw1701]

Here is a link to a pdf, mine is on page 3 called direct mainsflow. http://www.albionwaterheaters.com/pdfs/sales/mainsflow.pdf

Interestingly, the diagram is misleading as to the height of the pipe connections, in addition mine has a removable flat lid unlike in the picture.

Given the rudeness of Albion when I rang for help, and the fact that I cannot seem to find pictures on the internet that look exactly like mine I am wondering if albion have changed the design of their system because it has major issues and/or design flaw. Perhaps the entry point of the boiler water is to near the surface which is allowing air to be pulled in causing all my rads to fail. Has anyone had an experince of albion mainsflow from around 6-7 years ago?

Thanks,

Tom.

 

[tjw1701]

Hi All,

Most of the system is being replaced soon thank goodness, the other day another radiator pin holed, this one wasn't even being used as it is in the spare room and was turned off, that's all rads except one in the house dead. Hopefully all the problems will go away when its replaced but I would love to figure out what on earth was wrong it in the first place.

Thanks.

Tom.