Heat bank & boiler connections

[Dan Robinson]

I still fail to see why a TS is any more susceptible to these problems than your run of the mill system. In fact any domestic system.

None of what you posted since page 2 is pertinent to a TS. And posts before that were just wrong.

 

[JonasX]

Thanks for the graph. Thermal stores with DHW plate heat exchangers have the bottom of the cylinder at low temperatures a lot of the time. Fill a bath quickly and it can be 25C at the bottom, well in most of the cylinder really. Fill a sink and the very bottom will be approx 25C, while the upper parts at say 65C. The plate heat exchangers are so efficient they extract most of the heat from the water. The graph clearly shows that thermal stores are highly efficient when the return temperature is around 25-30C. When heating a cylinder set to 65C the efficiencies only drop off when the cylinder is near up to temperature.

For most of the time the boiler is reheating the cylinder the efficiencies are exceptionally high as the graph shows. AT 30C return temperature, which is common on thermals stores, the efficiencies of the boiler are 97%.

 

[DeltaT2]

If you imagine that instantaneous water heaters are immune to legionella, then you are mistaken or have been misled by manufacturers' nonsense. There is legionella in the mains water; the concentration of sterlising chemicals required to kill it would be toxic to people. Problems will arise when the conditions allow proliferation.

Makes you wonder how we have survived all this time don't it?

My point is, as a routine, PHE in combis seldom get to 60 degrees on the secondary side for long enough to do anything to bacteria. In fact i doubt any PHE water (in the domestic sector) is kept at bacteria killing temperatures long enough to kill them all anyway.

The whole point is that it is potable water. It is not stored. It is changed frequently enough for Legionellas not to build up.

Oh, and with my store set at the temperatures it is currently set to, the water hits the TMV valve above 70. Goodbye Mr Legionella - if you're there.

You couldn't make this up??!! You are arguing about Legionella, when clearly your own pipes are full of it??!!!!

Yet another reason never to fit a SLUDGE BUCKET; they harbour Legionella!!!

I think with all things considered, the case for never fitting a thermalstore or heatbank has been won.

 

[JonasX]

Yet another reason never to fit a SLUDGE BUCKET; they harbour Legionella!!!

You made all that up. You can't figure out how they work never mind understand Legionella.

 

[Onetap]

Thanks for the graph. Thermal stores with DHW plate heat exchangers have the bottom of the cylinder at low temperatures a lot of the time. Fill a bath quickly and it can be 25C at the bottom, well in most of the cylinder really. Fill a sink and the very bottom will be approx 25C, while the upper parts at say 65C. The plate heat exchangers are so efficient they extract most of the heat from the water.

It is a thermal store, you clueless cretin. The clue is to be found in the name; it is a heat store, a depository for therms.

If the bottom is at 25 degC, then it is ineffective as a heat storage device. You need the top at more than 65 degC to generate DHW water at 60 degC. You can distribute DHW at 50 degC or less, but that brings you into the realms of legionella, as discussed above at length. You may get condensing return temperatures after running a bath, but these are temporary and unusual conditions. The majority of the heating season does not occur directly after running a bath.

The graph clearly shows that thermal stores are highly efficient when the return temperature is around 25-30C. When heating a cylinder set to 65C the efficiencies only drop off when the cylinder is near up to temperature.

It shows nothing of the sort.

Scrap the sludge bucket, fit an unvented storage cylinder. Fit a Vaillant WC controller, run at sub-55 degC return (condensing) temperatures for most of the heating season. The boiler runs at 80 degC flow for the brief periods when the cylinder needs to be reheated.

 

[Dan Robinson]

If only you knew half of what you thought you did

We have Puller arguing they store sludge, Onetap arguing they cause Legionellas... Unbelievable. I am not saying badly installed systems won't build up sludge. That is not the fault of a TS any more than it is a traditional boiler and S plan.

And to say a TS is more prone to forming dangerous levels of Legionella's disease than any other combi boiler - or traditional gravity fed cylinder is frankly pathetic.

 

[gaswizzard]

The very principle of design makes for these thermal stores to be a sludge bucket , think of them as one BIG LLH.

 

[Dan Robinson]

 

[gaswizzard]

Hey Dan , i'm not siding with anyone on here, but the truth be known they ARE a sludge collector, hydraulic seperation has a lot to answer for regards these units , cleaning/access plates would do wonders for these mahoosive LLh's.

 

[Dan Robinson]

Then it is not such a bad thing. But large quantities of sludge should not be forming in a properly design/installed system.


This is something the detractors are failing to realise (or at least freely admit).

This is why I find this thread laughable - yet another one spoiled by nitwits for the sake of it rather than for constructive advise to the OP.

 

[DeltaT2]

Then it is not such a bad thing. But large quantities of sludge should not be forming in a properly design/installed system.


This is something the detractors are failing to realise (or at least freely admit).

This is why I find this thread laughable - yet another one spoiled by nitwits for the sake of it rather than for constructive advise to the OP.

There has been very constructive advice given Dan/WS/Dr D/ BB. Don't buy or install the SLUDGE BUCKETS, we have had many, many installers, including my good self, telling you that they ALL sludge up, quoting sites, types of appliance etc etc......................What more can we say.

The reason it happens; I don't give a jot!! We'll just supply,fit & specify un-vented cylinders, cause they do the job & don't sludge up......

 

[gaswizzard]

Then it is not such a bad thing. But large quantities of sludge should not be forming in a properly design/installed system.

A well designed system will always be open for neglect, inhibitor rarely used after a drain down won't help these units, all the ****e & system debris will be collected in these units due to the way in which they are designed, NONE of these units are maintained EVER, this being said they will ALWAYS be a sludge bucket due to no fault of their own.

 

[Dan Robinson]

 

[gaswizzard]

http://www.jonrb.com/emoticons/whatever3.gif

With respect , if you knew anything about 'proper' system design you may think twice.

The very nature of these units makes them sludge collectors.

 

[Dan Robinson]

Apologies - your post got in front of mine -that smiley was for puller.