Help with 3 channel controller and Thermal Store

[glitglit]

Hi All,

I was wondering if you could provide some advice on a suitable 3 channel controller to work with a spec flue DS -10 Thermal Store.

I can send a drawing of my requirements and I hope someone can help as this is slightly complicated.

Also can you have Qty x 2 (3 channel) wireless programmable thermostats connected to one receiver at a thermal store tank?

Any help at all would be greatly appreciated

 

[ProDave]

Unfortunately you can't post pictures until you have mader 10 posts.

Can you derscribe what you are trying to achieve?  I presume 3 heating zones?

I would personally use programmable thermostats so they do the job of thermostat and programmer for each heating zone.

Plumb the system with a 2 port valve per zone, so the programmable stat opens that zones valve, and then the feedback contact from each zone turns on the circulating pump.

Then the other bit of course is the tank thermostat controls the boiler to heat the TS whenever needed.

 

[glitglit]

Hi Dave,

I am looking to purchase a 3 channel wireless programmable room thermostat with receiver.  I may require two programmable room thermostats one to be located downstairs and one to be located upstairs to measure temperature independently in the rooms that they are located in.  The three channel on both programmers are required for the following:

Programmable stat (located downstairs) output channel 1 = (DHW)

Both programmable room thermostats will then be wirelessly linked to the receiver.   Receiver to be located beside the Thermal Store Cylinder.

I have attached a basic drawing of our system and how I would the heating and DHW to be controlled.  I hope you can advise in terms of the components required and how this will operate successfully.

The Thermal Store Cylinder is called a Exel DS-10 (Thermal Integration/Specflue) which already comes complete with its own two channel controller built onto the store.  This two channel inbuilt controller will control the oil boiler (ie one channel switches on oil boiler for DHW and one channel switches on the oil boiler for central heating)

We require you’re Qty x 2  (3 channel wireless programmable room thermostat with receiver) to control this two channel built in thermal store controller.  So the wireless receiver would need to be located beside the two channel inbuilt controller so that they are electrically linked. The receiver unit is then connected to the two channel controller.  Controlling channel 1 economy stat (DHW) and controlling channel 2 the buffer stats (central heating) and then the third channel will control the boost feature that will wake up the channel 1 economy stat (DHW) for an hour on the inbuilt two channel controller.

We also need to activate the components around this thermal store cylinder such as:  Activate the radiator circulation pump if for example channel two (central heating) is required.   Activate automatic valve for downstairs if downstairs heating is required, or the other automatic valve if upstairs heating is required or activate both automatic valves if both upstairs and downstairs heating is required.

 

[glitglit]

Hi Dave, Apologies I hit the enter button and it sent without finishing my comments.

I am looking to purchase a 3 channel wireless programmable room thermostat with receiver.  I may require two programmable room thermostats one to be located downstairs and one to be located upstairs to measure temperature independently in the rooms that they are located in.  The three channel on both programmers are required for the following:

Programmable stat (located downstairs)

output channel 1 = (DHW)

output channel 2 = (Central Heating downstairs)

output channel 3 = (DHW boost 1hour)

Programmable stat (located upstairs)

output channel 1 = (DHW)

output channel 2 = (Central Heating upstairs)

output channel 3 = (DHW boost 1hour)

Both programmable room thermostats will then be wirelessly linked to the receiver.   Receiver to be located beside the Thermal Store Cylinder.  Receiver will then be wired to a built in 2 channel controller located on the store itself (comes with the DS-10 Thermal store).

The purpose of the 2 channel in built controller is to control the tank stats.  There are 1x tank stats at the top called Economy stat and 2 x buffer stats in the middle of the tank called buffer stats.

Econ stat is for DHW

Buffer stats are for central heating and DHW

Therefore only the Economy stat can be on or the buffer stats can be on.  Both cannot be on together.

So if I would like CH on for example downstairs, I would press the button on the 3 channel prg controller.  This would sent a wireless signal back to its receiver.  The receiver is wired to Zone 1 motorised valve to open and also the receiver is wired to the 2 channel controller to activate the buffer stats and the 2 channel controller will also activate the boiler and circulation pump.

Same principal applies if I would like to use the second 3 channel prg stat upstairs. So if I would like CH on for example upstairs, I would press the button on the 3 channel prg controller upstairs.  This would sent a wireless signal back to its receiver.  The receiver is wired to Zone 2 motorised valve to open and also the receiver is wired to the 2 channel controller to activate the buffer stats and the 2 channel controller will also activate the boiler and circulation pump.

So if I would like DHW, I would press the button on either the 3 channel prg controller upstairs or the 3 channel controller downstairs.  This would sent a wireless signal back to its receiver.  The receiver is wired to the 2 channel controller to activate the economy stats and the 2 channel controller will also activate the oil boiler and an inbuilt pump to draw water from the top of the store down through a Plate Heat Exchanger.

I hope that makes sense.  As I am not a plumber but hopefully you can advise and keep me on the right track.

Thanks again Dave

 

[ProDave]

You are over complicating it (and confusing me as to why you are doing that)

Each room thermostat needs to be just one channel, it's a programmable thermostat to control the room temperature, nothing more, nothing less.  You need one room stat per heating zone that you are having.

Don't try and complicate it by also having a hot water thermostat or control built into the room stat. Why would you want to do that?

I wonder if you are miss understanding how a thermal store works?  It wotks on the principle of keeping a big tank of hot water hot all the time. So when you want heating you just open a valve and turn on a pump and water flows to the radiators or under floor heating or whatever you have.

For hot water the incoming cold water passes either through a heat exchange coil in the tank, or in the case of the one you are looking at, through a plate heat exchanger, so hot water is heated as you use it. No need for any "controls" (except in this case a flow switcvh will need to turn on a circulating pump for the heat exchanger)  Think of it a like a combi boiler, hot water is available whenever you want it, no need to turn ther Dhw on or off.

Because the temperature of water in the tank can vary a lot, and can be quite hot, it's normal to supply domestic hot water via a thermal mixing valve so it's never dangerously hot.

As a quite separate control circuit, you need some means to heat up the thermal store. This is usually just the tank cylinder thermostat calling for heat from a boiler, and that may or may not also have a time clock as well. yout tank seems to over complicate that by having two tank thermostats which again just seems to cvomplicate it for no good reason.

Step back and think what you really need. Keep it simple.

 

[Sharpend]

Have to agree with our Dave here, reading through your descriptions was sending me spinning, far too over complicated for what you need to achieve? 

 

[glitglit]

Hi Dave and Sharpend,

I can explain the reasoning behind the complications:

I do not wish to have the Thermal Store constantly heated 24/7 365.  So under normally conditions the thermal store will be cold.

If I want hot water I need to press the hot water button or boost button.  I do not wish to walk to the thermal store and climb into the airing cupboard each time I want hot water.

Therefore I would like to have a hot water button on a 3 channel controller upstairs and also a hot water button on a controller should I be downstairs.

On the other occasions we I decide to just leave the upper part of the tank warm for DHW for a few weeks for example I still need the facility to switch this off without having to climb into the airing cupboard again to get access to the tank.

Hot water is controlled by what is called a economy stat located near the top of the tank.  But this economy stat has to be controlled by something.  Therefore it has to be told to come on and off when needed.  That is why I think having a 3 channel controller to do this is the best approach unless there is another way???  The "DHW button" on the programmable controller when pressed would then send a wireless signal to the receiver at the tank and the receiver would be wired to switch on the economy stat, switch on a flow switch and switch on a circulating pump for the heat exchanger).  And there would also need to be a power supply sent down to the oil boiler to heat the water in the TS upper section.

That's the reasoning behind having the Qty x 2 (3 channel progammable stat)

Programmable stat (located downstairs)

output channel 1 = (DHW)

output channel 2 = (Central Heating downstairs)

output channel 3 = (DHW boost 1hour)

Programmable stat (located upstairs)

output channel 1 = (DHW)

output channel 2 = (Central Heating upstairs)

output channel 3 = (DHW boost 1hour)

There is already a built in 2 channel controller located on the store itself (comes with the DS-10 Thermal store).  There is nothing I can do about that it comes with the package

The purpose of the 2 channel in built controller is to control the tank stats.  There are 1x tank stats at the top called Economy stat and 2 x buffer stats in the middle of the tank called buffer stats.

Econ stat is for DHW

Buffer stats are for central heating and DHW

Therefore I need a way to control the 2 channel built controller which in turn will then control either the Economy stat (DHW)or the buffer stats (CH).

Please let me know if I have justified my reasoning?  Please suggest an alternative way to control the DHW without having to go near the Thermal store i.e the comfort of my livingroom!

Please see attached my diagram showing the layout of my heating system.

Thanks again guys

View attachment Basic Heating Control Overview.doc

 

[steptoe]

How long do you think you will be waiting to get hot water if the tank is cold,? It won't be measured in minutes, that's for sure,

Also, you don't need a 3rd channel for boost, most good 2channel programmers have variable boost times inbuilt, 30/60/90/120 or 30/60/120/180 minutes for example, 

 

[Sharpend]

Surely by operating it the way you describe defeats the object of it in the first place? If you have a tank of water that is cold and you need to heat it in order to get it to produce hot water then how long is the initial heat up time? Surely this will be inefficient useage of the system?

 

[Jim96]

The purpose of the system seems to contradict itself if used/created in this manner 

 

[Sharpend]

So reading the literature it would seem that this can indeed provide hot water within minutes? http://specflue.com/catalogue/download/152 I will hunt for a technical spec sheet if possible. 

 

[ProDave]

You are completely miss understanding what a thermal store is all about and I suggest you forget about using that and fit a combi boiler instead for the way you want to operate it.

I can assure you it will be an hour or more more from pressing your "DHW" button to getting any useful temperature hot water out of the thing.

You don't have to keep the store hot all the time.  It's pretty normal to use a conventional 2 channel central heating programmer.  Use the "hot water" output to control what times the boiler fires up (under control of the tank stat) to charge the store, and use the CH channel of the programmer to select what times the heating system draws water from the tank.

The whole point is you don't haver to go pressing buttons to get hot water.

I think you need to completely re evaluate your heating and hot water requirments and choose something that is a bette match.  The biggest unique feature and reason for fitting a thermal store is the immense flow and pressure available from the hot water to feed for instance a REALLY good powerful shower with a far better flow rate that you will get from anything else.

 

[glitglit]

Hi All,

I can assure you that I have been informed by Specflue that this Thermal Store system DS-10  is capable of providing hot water within minutes because of its top down heating feature.  Also because of the economy stat located at the top of the store you are only heating 40 litres of water and not the entire contents of the tank.  So it should provide instant hot water at the touch of a button.

1) So my first preference is to press a button on a controller to get DHW when I need it.  The surplus heat may remain in the store for the next day for example.

2) Then my second preference (if this is not effective) is to leave the DHW on all the time i.e continously heating the 40litres 24/7 365 controlled by the economy stat.  i.e when the economy stat is lower than the temp setpoint it turns on the oil boiler, flow switch and PHE pump.

Therefore the push button on the controller for DHW is on all the time.

And finally controlling the central heating via a controller upstairs and a separate controller downstairs which should be wireless linked to the same receiver located at the thermal store.

So if I push the button for heat the overrides the button for DHW and therefore only one button can be activated at one time.  Then if I push the button for DHW then the Central Heating button deactivates.

Surely this is a basic setup.

One downstairs controller with 3 channels to cover downstairs central Heating, DHW and DHW boost

Second controller upstairs with 3 channels to cover upstairs Central Heating, DHW and DHW boost

A receiver located at the Thermal Store and wirelessly linked to the two x 3channel programmers as mentioned above

A 2 channel Thermal store controller wired to the receiver

I thought I had given this alot of thought.

Can you suggest a better way of doing it based on the preferences that I have outlined above?  I basically want control of CH and DHW both upstairs and downstairs on two separate units.

The receiver then has to activate 2 x automatic valves for upstairs and downstairs CH as well as the two channel in built controller

The 2 channel controller then activates the rest of the items, i.e the econ stat, flow switch, PHE pump, oil boiler etc.

Please suggest and easier way but using my requirements

Thanks guys

 

[Davethsparky]

Why not ask spec flue to suggest a control system which works with their product to give you the desired functionality?

 

[Sharpend]

Took the words right off my page there Dave!! 

Surely specflue would be best placed to tell you what controls would be best suited to their system? 

 

[ProDave]

Well all I can say is this is a peculiar hybrid tank. It's not operating like a "proper" thermal store so I really can't see the attraction of it.

It's going to need a very much more complex control system for some rather dubious benefits of having to press a button and wait for hot water.

If it's only going to heat the top 40 litres, how is the heating going to work?

I would either get the manufacturer to design the complete control system or seriously think again about what to use.

 

[glitglit]

Hi Guys,

Specflue recommend that the TS thermostats control the oil boiler.  Meaning the tank is always warm.

The tank being warm will either be on the economy stat mode (which is the stat at the top of the top ...ie 40 litres) for DHW

Or the tank will be on the buffer stat mode (which are the two stats centrally located in the tank...ie 250litres) for heating radiators and DHW.

Some control device needs to be installed to tell the stats which ones should be actually be switched on i.e economy stat for DHW only.  

I need some controller but I dont know what type.

Now if I have one controller for example downstairs then I cant change anything when I am upstairs.  That's why I need two controllers.

So even if I was to look at a basic Qty x 2 controller system one located downstairs and one upstairs.  All I want to do is switch between Economy stat mode (for DWH) to buffer stat mode (for central heating).

Then when the house is warm I switch back from buffer stat mode to economy stat mode.

These two modes are linked to an inbuilt two channel controller.

So can anyone help me achieve what I want based on the information above????

Then the only last complication is that I don't always want the Thermal store to be warm so I want to switch off both modes.

That in language form seems very straight forward to me but as I am not a plumber or electrican I cannot put it into practical terms.

Hopefully you guys can help me do that.

Thanks again, please let me know your thoughts.

 

[Davethsparky]

I doubt you will Babel to achieve this with off the self products and will likely need something which can programmed to perform the functions that you want. 

Conventional controls are are based on simple switches and will not allow for a sensible control from multiple locations.

 

[ProDave]

So what you are after is a "summer / winter" changeover, so in the heating season it heats the whole tank for heating and hot water, and in the summer just the top portion of the tank just for hot water.

I still think the whole system is a fudge. I doubt you are going to get a control system that does that properly just by connecting off the shelf parts. I think a relay is going to figure in the wiring somewhere as well.

If I had to do the job then no doubt with ALL the instruction manuals, and a clear and correct plumbing diagram, I could sit down and design something, but I am not going to attempt that remotely on a forum as the potential for getting it wrong or missing something is far too great.

If the manufacturer has designed such an unusual hybrid system, then surely they can advise on how to conect it.

 

[glitglit]

Hi Dave,

That is basically what I am trying to achieve.

All I really want to do is switch between the summer and winter mode.  I assume that is why they have an inbuilt 2channel contoller (one channel for summer and one channel for winter)

Thats why it seems so basic.  Surely there is a controller out that if I press a button I can change from summer over to winter mode.

Even if I just have one controller in the house to make this as easy as possible.

Can you provide any advice based on that?

Thanks again