Heat exchange coil leaking into heat store

[bab]

In answer to not running the system.If the cross from mains cold to htg in the store is only a cm per hour i would keep running the system untill u decide what to do but isolate the cold water main into the coil when u don't need hot water.Never isolate the heating or the boiler & try to run the system as they both expand & contract via the header tank on the thermal store.I have experiance of Albion cylinders failing on the copper & not seals so i would advise on going with stainless next time.As long as you only turn the water on to the coil when you require it the pressure will be reduced in the coil and it may not leak at all.Don,t rush into any thing if you can run like this 4 a while.

 

[shellards]

Thanks to bab for comments on isolation of cold water main into coil when not required. I shall probably do this. (Though might this not increase the possibility of cross contamination from the heat store to the domestic hot water? This is all getting a bit too complicated for my taste.)

I think I understand your point about the need not to isolate the heating; however, I would have thought that I could simply switch off the heating pump which would in effect isolate the heating without, I think, leading to any dangerous outcome.

I am still unclear as to the risk to my central heating if I continue to run it as normal in the interim. Oilman did make a rather concerning comment as regards this in an earlier stage of this forum, saying that the risks would only exist if water to the central heating were drawn directly from the heat store. This in fact is what happens as I have made clear, but oilman has not returned to the subject with any urgency.

 

[bab]

In my opinion the leak in the coil in your store will be a pin prick (1cm @ 2.1bar) per hr?.When u isolate the mains as long as u don't open a hot tap the coil will depressure to the same as in the store which may not be infected except 4 inhibiter & if your not drinkin the hot water it should not be able to enter the cold water main because the pressure reducing valve on the cold water main should have a built in check valve in it to stop heated water backflowing when the cold is off, & yes it is correct that the heating is direct off the thermal store just as your boiler is direct to heat it. Its the opposite to an old style cylinder but I think the coil is made up from a bunch of 10mm pipes to icrease the surface area for fast temp collection.

 

[Agile]

I have a couple of digital pH meters and a TDS meter. Useful for diagnosing the cause of system faults like holed cylinders!

Any competent engineer will know that inhibitor is required and particularly if the water may not have much hardness.

I am not very sure that I would rush to blame the designer because adding inhibitor is really part of the installers job!

Tony

 

[ChrisR]

"Damage" to your heating system only comes, I believe, from the extra oxygen being introduced in the fresh water through the leak. This is what allows your radiators etc to corrode. There should have been a passivating layer on the ferrous material as a result of the initial corrosion inhibitor. This will degenerate to some extent in unfavourable conditions, but considering the rate of fresh water ingress you're looking at, I don't think it would be significant.

 

[shellards]

Agile says:

Any competent engineer will know that inhibitor is required and particularly if the water may not have much hardness.

Something is puzzling me about my present situation. Inhibitors were used in the heat store and central heating/boiler circuits - (perhaps not in sufficient quantity, as previously discussed.) However, surely damage could also have occurred on the domestic hot water side of the heat exchanger which has failed. I am under the impression that it is particularly the conjunction of ferrous and copper elements in the system which leads to damage (through electrolytic activity?). This system has a small expansion vessel associated with the heat exchanger, to take up expansion of water resting in the heat exchanger coil. This vessel would have had ferrous components I believe. Significantly perhaps, there is the appearance of rust on the junction of the expansion vessel with the copper pipe leading to the heat exchanger. I had actually ordered a replacement expansion vessel as I was concerned about this.

 

[bab]

morning.Have to be more careful what i say or i might be told i'm talking nonesense.The expansion vessel u are talking about must be on the potable (drinking) side as the thermal store has a F/E cistern. NORMALLY expansion vessels on heating r red & those on potable water are blue or white.The data badge on the vessel will give u the normal charge pressure for that vessal.HTG vessel's around 1 to1.5bar but potable i think much higher 2.5 to 5bar depending on the unit its being fitted on.

 

[shellards]

Yes, the expansion vessel is on the potable side. And in addition: A good New Year to you all, in particular those who have been kind enough to take an interest in my obscure plumbing problems.

 

[Agile]

The expansion vessel for potable water should be made of stainless steel and either shiny or white.

Mild steel expansion vessels for treated water are colourse orange !

Tony

 

[shellards]

Agile says:

The expansion vessel for potable water should be made of stainless steel and either shiny or white.

The external apperance of the vessel fits this description more or less. It came as part of a package specified by the system designer. Nevertheless I have emailed 2 photographs for posting, the first showing the expansion vessel and the second showing the corossion which had concerned me and which looks - to me - like rust.

 

[albionagony1]

I have the same problem as refered to in the previous e-mail chain

//www.diynot.com/forums/viewtopic.php?t=39780

My research to date suggest that the Albion Mainsflow multi coil system is highly suspect. I would appreciate any pointers as to suitable reliable replacement thermal stores; indirect and Y plan. I live in the Thames Water area in London and have an in line limescale unit.

My Albion coil has blown after approx 7 years; the system has been subject to regular annual maintainence by qualifed enginners. I'm a mere hosueholder trying to a suitably qualifed person to fix his system. The story seems to be that simple fast tap start/stop is enough to cause the Albion mutli coils to vibrate against one another which eventually result in a leak. Albion not interested; warranty was only 5 years per them.

If anyone involved in the prior dialogue happens to know how that Albion unit was fixed and/or repalced that would be helpful.

 

[Agile]

My Albion coil has blown after approx 7 years; the system has been subject to regular annual maintainence by qualifed enginners. I'm a mere hosueholder trying to a suitably qualifed person to fix his system. The story seems to be that simple fast tap start/stop is enough to cause the Albion mutli coils to vibrate against one another which eventually result in a leak. Albion not interested; warranty was only 5 years per them.

I wonder how BigBullShit is going to answer that!

He thinks that they are the best thing since the Lancaster bombers which were launched while he was at school.

Tony