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
What I had in mind was
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
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
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
What I had in mind was
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
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