DIY Heat Bank Part Deux

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OK lets try this again

The (electronics) engineer in me cannot let this go so I would still like to explore my idea further but I do not want this to turn into another personal flame war

Some ground rules this time :-
1) I am aware of the great presurized Vs Heat bank Vs Combi Vs traditional tank storage debate.
It's a good debate and one which I will go through again before I do anything. However, this thread is about whether it's possible to achieve what I want to do with what I already have and a few extra bits so please don't go down the "TECHNOLOGY A STINKS, YOU WANT TECHNOLOGY B" road.

2) "Control rodent A" might well think that "Control rodent B" is an oxygen thief who should not be allowed near the giant rotating wheel of life. That's fine and you're welcome to that opinion but please keep it out of my thread

***** edited by fumbduck in light of a myriad threads going on about the first topic******
What happened to the first post is over and done with. The mods did what they felt was right at the time and I have absolutely no issues with their decision. It's ultimately their board and I have full respect for that since I too moderate an online community and know what can happen
Please don't keep dragging it up. It's over and done with as far as I'm concerned. Let's just make sure this thread doesn't go back there
***************************************


OK, rant over. Can we please continue what was (from what I saw) a largely friendly discussion where I for one was learning stuff
*************************************************************************************
To recap, right now I have this
current.jpg


What I had in mind was
new.jpg


The boiler is an aging Crane Cavalier with a water jacket temp sensor, no tank temp sensor in the system.
HW is currently generated via indirect gravity heating of the cylinder
CH duties are handled via a pump direct off the boiler manifold. The pump is controlled via a single room thermostat
The whole system is also overseen by a very basic "once"/"twice"/"H+W on" type mechanical timer which I'm sure most are very familiar with.
The whole system is housed in a 1960s built 3 bed detached with washing machines, dishwashers, a (hopefully!) high flow shower, a bath (bath and shower are the same so will not be in use at the same time) and long term ambitions for an en suite loft conversion, again with shower.
Current measurements indicate a water pressure of circa 3.5bar with a flow rate in excess of 20L/Min which I expect to improve when my underground incoming main is replaced in plastic to fix the leak I have at the moment
One thing I missed first time round is that the external walls are all rockwool (I believe) cavity insulated, loft is fibreglass insulated on both floor and roof itself and all the windows are newish plastic. So it's an easy place to heat, calculated roughly as a 13KW load. The current system functions very well for what it is and has no trouble maintaining room temperature and eventually water temp

So, given that financial constraints prohibit me from fitting a new high efficiency boiler right now where we'd got to last time was that the system might work but the cylinder would need to be either direct gravity heated or indirect heated but with a pump in the system

I am still confused by the whole gravity feed issue. Tests this morning show that I am able to achieve pretty respectable cylinder temperatures using in the current system so I could achieve good store temperatures too I assume. Can someone explain to me why the current indirect gravity system will not work with the planned heat bank setup please.
One thing worth mentioning. When I replaced the original leaking galv cylinder some 4 years ago I fitted what was considered to be the "proper" cylinder for a gravity system. I know that the indirect coil was larger than "standard" but forget whether this refers to the pipe diameter (28mm) or the actual length, as it were, of the coil. Or possibly both.

Having given it some thought last night if I do have to force pump the indirect circuit it might be possible. I have room in the coil feed side (but not return) for an inline pump. Would this work in general? If so it would be simpler to rig up than replumbing for direct heating. Plus, if it all goes pear shaped it's easier to return to the original (current) system :)
The only way I can see this electrically working with the current components is to have this pump effectivly self controlled via a tank thermostat exactly as the CH system pump is currently self regulated by a room thermostat.
This leads to another concern for the current boiler setup which runs a sort of Y setup by default. At the moment the boiler output is either activly pumped round the radiators or gravity feeding the cylinder coil (or "off" when the boiler jacket temp reached the thermostat level).
If I fit a pump in the cylinder feed independantly controlled by a tank thermostat I will almost certainly end up with both HW and CH pumps running at the same time giving me a mid position Y system rather than the current HW or CH but not both setup. Will this give the boiler issues where it can't cope with the demands of both systems at the same time?
I currently have a legacy, unused, single 3 core mains cable which goes from the boiler to the cylinder cupboard which, I assume, used to be for a tank thermostat. This could be used to provide switched power from the overall time controller to the pump circuitry

Another thing, not necessarily a concern for the 1/2 way house interim solution but definitely a factor in the final solution :-
If I continue to run a similar boiler setup where the store is indirectly heated and I use a Y plan setup to run this and the CH then I'm going to end up with some very hot radiators I think. Would I need to run a mixer of some description to overcome this and keep radiator temps below the dangerously hot level? Or do I need to run a totally different setup to drive the CH?

In a similar vein. The final mixer on the pressurized hot water supply. Would this need to be a thermostatic unit to maintain the desired output temp for as long as possible or will a simple mixer work and you just live with the gradual decrease in temperature as the store cools?

Finally, there were some very useful links and contacts in the original thread. I would be most grateful if people could repost them here or email to me at :-

pritchard(underscore)stephen(at)yahoo(dot)com - replace the bits in brackets with their real email equivalents ;)

Also, ChrisR, you posted an Alpha Laval reference. Can you also get hold of the CB14-40 units (100KW by my reckoning) which I think would be more appropriate to my final goals. Feel free to respond off board on the above email if you'd prefer

Many thanks for any more input and let's play nice people :D :D
Oh and sorry for the War and Peace nature of this post :)

+++++++++++++++++++++++++++++++

Thanks W S

This time I have commited it to Notepad just in case.....

Anyhoo, in the original there was some input from somebody (I'm sorry but I forget who it was) that the boiler might be undersized. I would really appreciate any additional input on that subject

I'm not just looking for it's a brilliant idea type feedback but would greatly appreciate "it won't work because" as I don't want to head off down a dead end
 
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W

Water Systems

Big Burner last night gave links to this:
http://www.compakva.com/UK/Compakva32.asp

A pakaged combined plate heat X and temperature valve, which restricts flow through the plate to acheive the DHW setpoint (not blending). It can be in a nice cabinet. The only extras you need to convert a cylinder to a heat bank is a pump and flow switch.

It is aimed at the district heating market. Price unknown, so not known if financially feasible.

++++++++++++++++++++++++++++++++++++
Your second drawing is using al the same water in the CH system and cylinder. The heat exchanger coil is slowing down heat transfer from the boiler. Heat exchangers are for various reasons. A high pressure circuit can heat a low pressure one, contaminated chemical dosed water can heat potable etc. They separate water circuits.

May as well not use the coil and connect the boiler directly to the cylinder without a coil - faster warm up and the gravity will work better. The gravity may be fine for a temporary arrangement, and the coil waiting for future use.

If the cylinder heat up now OK (to you) it will also when connected directly, and probably better.

You have a few choices:

1. Leave boiler as it and connect the cylinder directly on gravity (not through the coil) - as per your second drawing.

2. Put a pump on the flow or return pipe of the DHW from boiler heating the cylinder via the coil. Do not have a valve or pump on the open vent pipe - a clear path to the F&E tank. The boiler will need to be set to 70 to 80C and cylinder stat fitted ~25% off the bottom.

You now have two pumps and a non-return valve must be fitted after each pump. The room stat switches the CH pump and boiler and cyl stat switches the DHW pump and boiler. A cheap £5 relay from Maplin has to be used - being an electronics man you can figure the wiring out, I'm sure. The boiler controls remain the same.

But you now have a boiler that needs to operate at full temperature (the makers say it should anyway). If you want full temperature for DHW and reduced for rads then fit a pipe stat on the CH flow from the boiler - available from BES. This cuts out the boiler only, not the CH pump. So the boiler is maybe on max temperature setting an the rads temp controlled by the pipe stat sensing the flow to the rads.

Fit an F&E tank for the "cylinder only" - the water (heat tranfer fluid) just stays there and only one 1 litre can of inhibitor is needed. This way there will be vastly reduced corrosion inside the cylinder and the existing system can remain largely the same except for an added DHW pump.

I hope this helps.
 
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Thanks again!

I think I would go option 2) and pump the existing gravity system. The main reason for this is should it not work out (not that I have doubts you understand :D ) I can simply remove the pump/non return and restore the current known working system. If I replumb for direct gravity feed then I have to reverse all the replumbing to get it back into a working state.

All of the heat exchanger gubbins can then be t'd off on and back into the current pipework pretty simply and again easy to reverse should the need arise

The electrics should be simple enough too and somewhat fortuitously there's already a non return valve in the CH plumbing
It looks like the system should be a goer and I'm inclined to try as long as I can source a reasonably priced heat exchanger. If I procede I'll keep everyone posted. Keep an eye on the DIY Disasters forum :LOL: :LOL:
 
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Water Systems

Have an F&E tank only for the cylinder - they are cheap enough. Yo can fill it with a hose and no overflow if need be. A tight fitting lid and fill to 25% off the bottom.

A 100kW plate can be bought for under £100. Trade places tend to be expensive for the walkupper. The last time I priced up a Gledhill plate it was around £85-90 inc postage. They use a good one too.

You will get mains pressure DHW for a fractiion of the price of a Megaflow - and no
 
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There are an awful lot of words on this topic, but the gist of what's being described is a home-made version of what one manufacturer calls a "Pulsacoil 2000".

If you're thinking of fitting a Gledhill PHX (GT017) then why not just go the whole hog and buy the PCB (GT152) and sensors (GT146 and GT153)?
 
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Softus said:
There are an awful lot of words on this topic, but the gist of what's being described is a home-made version of what one manufacturer calls a "Pulsacoil 2000".

Not quite.That is an all eletric heat bank - which is simpler as no boiler to connect onto. The problem here is the boiler conectivity.

If you're thinking of fitting a Gledhill PHX (GT017) then why not just go the whole hog and buy the PCB (GT152) and sensors (GT146 and GT153)?

You need the senor pockets. Fitting a Danfoss temperature valve that restricts flow through the plate, while sensing the DHW temp, is worth doing. See the APV link and info, they show a drawing.
 
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Interesting idea W S

I'll try my local supplier and see if he can get a good price on a Gledhill plate

Built up a pretty good relationship with him installing my folks Megaflow setup last year so I always get pretty good trade prices :D
 
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Water Systems

Try the local man then ring Gledhill direct. They mail the part. The local man may get a cheaper plate for you of a different make. The Gledhill plate is made by Swep.
 
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Will do

Forgot to mention, assuming I go ahead (getting more and more keen by the minute to do so, cost permitting) I'll start off using the existing storage tanks as F&E for the cylinder. Again, easy to reverse in the event of unforseen performance issues

If all goes well then I'll investigate more permanent solutions :D

Can anyone ofer advice on pumps for the system. I'm not sure what kind of flow rates I need to be looking for although on the exchanger side I guess this will be determined by the plate itself :confused:
 
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Water Systems

Grundfos 15-50, 5 metre head for DHW and plate. Yes, you can keep the extisting large cold water storage tank as an F&E tank.
 
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"""The boiler is an aging Crane Cavalier"""

My father worked there as a trainee draughtsman for a short time before he saw a bit more sense.

He took me round the works when I was about 14 and I was surprised to see all the bluish green molten metal they used to cast large valves.

Tony
 
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MOD 2
don't start it off again


This one is at it gain! You are deleting posts again. LEAVE THEM ALONE!!! All you have done is p1ss off a lot of people. Leave the job to someone else, you are no good at it.
 
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Water Systems said:
Softus said:
There are an awful lot of words on this topic, but the gist of what's being described is a home-made version of what one manufacturer calls a "Pulsacoil 2000".
Not quite.That is an all eletric heat bank - which is simpler as no boiler to connect onto.
The Gledhill Pulsacoil control system pays no heed to the heat source being electric, other than the immersion element relay (which I didn't suggest was either purchased or installed), so my post still applies.

The problem here is the boiler conectivity.
Well, the boiler is already connected, so that's hardly what I'd call a problem.

If you're thinking of fitting a Gledhill PHX (GT017) then why not just go the whole hog and buy the PCB (GT152) and sensors (GT146 and GT153)?
You need the senor pockets.
Of course, but why make that into a problem? I expect that the relevant sections of pipework, complete with pockets and HX connectors, can be purchased from Gledhill.
 
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Agile said:
"""The boiler is an aging Crane Cavalier"""

My father worked there as a trainee draughtsman for a short time before he saw a bit more sense.

He took me round the works when I was about 14 and I was surprised to see all the bluish green molten metal they used to cast large valves.

Tony

LOL

The darn thing is probably working just as well today as it was then too

In the 10 years I have owned the house (as a rental property until this year) it has never once had any issues other than eating 2 thermocouples. If it wasn't half the size of the kitchen with a bigger gas habit than Johnny Vegas I wouldn't change it even now :D

Softus,

Yes the proposed system is analagous although it seems to me that their BoilerMate system would be the closest match. Agree though the actual method of providing heating to the cylinder is mostly irrelevant. The "magic" of the system is what happens with the heat, not how it got there kind of thing
 
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Reliability, Reliability, Reliability!

I am removing a Pulsacoil unit from a customers house in the next couple of weeks. The landlord is mightly p****ed off that it keeps locking out causing the tenants to give him grief. Gledhill have sent their own engineers out in the past, but their callout charges have vastly swamped WS's 'unvented service charge'. This is on a new development with about 30 other properties all having the same system, so I am going to mailshot the others to see if I can get other replacements out of it!

So if you want a second hand pulsacoil unit/ sensors/pump/heat exchanger (albeit flaky controller which keeps tripping out) then let me know. Otherwise its all going to the scrappy! The heat exchanger is one of the biggest Ive ever seen at around 35cm x 15cm x 15cm.
 

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