Question on Simplest Pressurized Storage Solution

[mpilihp]

OK I think I understand how it works but Im trying to build to this with my existing system. The main difference is I have zone circulators instead of zone valves. My Problem is in section 4:

4) Heating with oil
If there’s demand from one or more zones and the storage is below 140, then the storage aquastat contacts are closed. This passes the zone demand signal to the oil boiler demand relay, which will turn on the oil boiler. At this point, the primary flow is from the oil boiler through the zones and back to the oil boiler. As in the case with the wood boiler, there may be some small amount of flow into or out of storage based on the difference in flow rates between the oil circulator and the load circulator. This should be minimal and not be a big concern.

with circulators do not have limit switches, so Im trying to figure out how to cause a contact closure when a zone calls for heat and the zone circ controller activates a motor. I could wire a relay parallel to the zone circ controller on the thermostat connection so that when the call for heat is seen here it closes a relay and on the other side of the relay it closes the circuit to activate the demand relay which would provide 120v ac to the oil boilers burner motor. Does that make sense?

Now I need to provide a means to stop ghost flows through my heat zones when the wood boilers circ is running. I was going to get zone motors with IFCs in them but that wiring I stated above is alittle involved. I was thinking what if I installed zone valves in line on the heat zones and have them activate in parallel to the zone circ from the thermostat and then I could use the limit switch on the zone valve for the demand relay. Hows that sound??

~ Phil

 

[Nofossil]

OK I think I understand how it works but Im trying to build to this with my existing system. The main difference is I have zone circulators instead of zone valves. My Problem is in section 4:

4) Heating with oil
If there’s demand from one or more zones and the storage is below 140, then the storage aquastat contacts are closed. This passes the zone demand signal to the oil boiler demand relay, which will turn on the oil boiler. At this point, the primary flow is from the oil boiler through the zones and back to the oil boiler. As in the case with the wood boiler, there may be some small amount of flow into or out of storage based on the difference in flow rates between the oil circulator and the load circulator. This should be minimal and not be a big concern.

with circulators do not have limit switches, so Im trying to figure out how to cause a contact closure when a zone calls for heat and the zone circ controller activates a motor. I could wire a relay parallel to the zone circ controller on the thermostat connection so that when the call for heat is seen here it closes a relay and on the other side of the relay it closes the circuit to activate the demand relay which would provide 120v ac to the oil boilers burner motor. Does that make sense?

Now I need to provide a means to stop ghost flows through my heat zones when the wood boilers circ is running. I was going to get zone motors with IFCs in them but that wiring I stated above is alittle involved. I was thinking what if I installed zone valves in line on the heat zones and have them activate in parallel to the zone circ from the thermostat and then I could use the limit switch on the zone valve for the demand relay. Hows that sound??

~ Phil

I don't have a lot of first-hand experience with circulator based systems. The first issue is that there must be some signal generated by the zone circulator controller that tells the oil boiler that there's demand. It wouldn't go directly to the motor on the boiler, because there has to be some aquastat involved. In my case, the 'demand' signal do the boiler is a contact closure. If yours is the same, then life is good.

Ghost flow through the zones is a potential problem I like the IFC idea, and perhaps there are plumbing techniques that could minimize the risk. A separate inlet to the top of storage for the wood boiler might be a solution. This means that the flow from the wood boiler to the zones would be through the top of storage, but that's not necessarily a bad thing. Some manufacturers suggest exactly this approach.

 

[mpilihp]

Hi thanks, my backup system is not like yours as its a oil boiler with an internal tank that it must keep warm. Currently im set up in series and the wood boiler just keeps it hot. But once I get an indirect DHW storage tank I will also add in the hot water storage and then put the boilers in parallel. Ill let the oil boiler go cold when its not needed. I was going to do this with a relay such as your demand signal but use it to control the 120V feed to the oil boilers burner. It doesnt take it long to get up to temp and its a short term solution as I plan on replacing it as you did with a gas fired on demand unit.

So is putting zone valve inline with my 007 pumps an OK way to do what I want to accomplish? Get IFC functionality on my heat zones and then have a contact closure available for the demand call circuit?

~ Phil

 

[WoodNotOil]

If I am understanding you correctly, you have circs for each heating zone instead of one load circ and zone valves. In that case, I would think that all zone circs would act like the load pump in the diagram. Each would have to have the ability to charge the relay that is connected to the storage tank aquastat and oil boiler high/low aquastat. I would think that the aquastat on the oil boiler would need its power feed routed through the tank aquastat. That way when the tank aquastat goes below 140*, it closes allowing electricity through to the oil aquastat which then kicks on the burner and heats up. This would also need to turn on the oil circ. That way if the storage is above 140* there would be no electricity going to the oil setup at all. The zone would get some low temp water while the oil heats up, but you are right that it does not take long for the oil to come up to temp.

Was that what you were asking about? I hope that is some help.

 

[mpilihp]

Yes in effect when a zone calls for heat it turns on its zone circ and if the wood boiler is running and its circ is running there would be in effect 2 circs running. THere isnt a seperate circ for the oil boiler.

So in effect it would all work the same as your setup for heating from the wood boiler, charging the storage from the wood boiler, difference is when heating from storage its just the zone circ running to draw the water. And when its time to activate the oil boiler thats my issue. Yes I would run a 24vac signal through the NC contacts on the wood boiler aqustat and the NC contacts on the storage aqustat and then through?? for a Contact closure from the zone call for heat. When all three are closed it would operate a relay that would then provide the 120v to the oil boiler aqustat.

And im trying to figure out the best way to get that contact closure from the zones. I need to spend money to deal with the ghost flow issue and Im wondering if im best off to put in zone valves after the pumps and then have the contacts on them to do this like you have.

~ Phil

 

[WoodNotOil]

Since you don't have zone valves, there shouldn't need to be 24vac in your system. Your thermostats in the house are hooked to a relay that sends 110vac to the zone pump. You want that same 110vac to the other aquastats. Honeywell aquastats can, and I think usually do, run 110vac through them. I think that is where your confusion is.

If you are trying to stop ghost flow with zone valves that does add 24vac into the picture. In that case isolate it from the 110vac using a DPDT relay where the 110 charges the poles to switch it and 24vac actually passes through the relay. This will require a 24vac transformer in your system or pulling power from an existing one if there is one.

Yes in effect when a zone calls for heat it turns on its zone circ and if the wood boiler is running and its circ is running there would be in effect 2 circs running. THere isnt a seperate circ for the oil boiler.

When you go to primary secondary hookup I think you would need to add a circ on the oil boiler as the zone circs will pull off of storage unless one is there.

So in effect it would all work the same as your setup for heating from the wood boiler, charging the storage from the wood boiler, difference is when heating from storage its just the zone circ running to draw the water. And when its time to activate the oil boiler thats my issue. Yes I would run a 24vac signal through the NC contacts on the wood boiler aqustat and the NC contacts on the storage aqustat and then through?? for a Contact closure from the zone call for heat. When all three are closed it would operate a relay that would then provide the 120v to the oil boiler aqustat.

I don't understand this one. In Nofossil's diagram the wood boiler aquastat is hooked up to the wood circ with 110vac. When the wood is hot enough water circs to the zones or storage depending on demand. The tank aquastat should see power when a zone calls to check if it is up to temp. If it is above 140*, the power does not go past that aquastat. If it is below 140*, the power goes on to the oil aquastat and circ.

And im trying to figure out the best way to get that contact closure from the zones. I need to spend money to deal with the ghost flow issue and Im wondering if im best off to put in zone valves after the pumps and then have the contacts on them to do this like you have.

Zone valves would be redundent and expensive after each pump. You could replace the pumps with ZVs and have only one load pump like nofossil's diagram.

Perhaps I am misunderstanding something here with what you are saying. Are you asking for clarification on running in series or primary secondary? I was assuming primary secondary.

 

[WoodNotOil]

Since you don't have zone valves, there shouldn't need to be 24vac in your system. Your thermostats in the house are hooked to a relay that sends 110vac to the zone pump. You want that same 110vac to the other aquastats. Honeywell aquastats can, and I think usually do, run 110vac through them. I think that is where your confusion is.

If you are trying to stop ghost flow with zone valves that does add 24vac into the picture. In that case isolate it from the 110vac using a DPDT relay where the 110 charges the poles to switch it and 24vac actually passes through the relay. This will require a 24vac transformer in your system or pulling power from an existing one if there is one.

Yes in effect when a zone calls for heat it turns on its zone circ and if the wood boiler is running and its circ is running there would be in effect 2 circs running. THere isnt a seperate circ for the oil boiler.

When you go to primary secondary hookup I think you would need to add a circ on the oil boiler as the zone circs will pull off of storage unless one is there.

So in effect it would all work the same as your setup for heating from the wood boiler, charging the storage from the wood boiler, difference is when heating from storage its just the zone circ running to draw the water. And when its time to activate the oil boiler thats my issue. Yes I would run a 24vac signal through the NC contacts on the wood boiler aqustat and the NC contacts on the storage aqustat and then through?? for a Contact closure from the zone call for heat. When all three are closed it would operate a relay that would then provide the 120v to the oil boiler aqustat.

I don't understand this one. In Nofossil's diagram the wood boiler aquastat is hooked up to the wood circ with 110vac. When the wood is hot enough water circs to the zones or storage depending on demand. The tank aquastat should see power when a zone calls to check if it is up to temp. If it is above 140*, the power does not go past that aquastat. If it is below 140*, the power goes on to the oil aquastat and circ.

And im trying to figure out the best way to get that contact closure from the zones. I need to spend money to deal with the ghost flow issue and Im wondering if im best off to put in zone valves after the pumps and then have the contacts on them to do this like you have.

Zone valves would be redundant and expensive after each pump. You could replace the pumps with ZVs and have only one load pump like nofossil's diagram.

Perhaps I am misunderstanding something here with what you are saying. Are you asking for clarification on running in series or primary secondary? I was assuming primary secondary.

 

[mpilihp]

And im trying to figure out the best way to get that contact closure from the zones. I need to spend money to deal with the ghost flow issue and Im wondering if im best off to put in zone valves after the pumps and then have the contacts on them to do this like you have.

Zone valves would be redundant and expensive after each pump. You could replace the pumps with ZVs and have only one load pump like nofossil's diagram.

Perhaps I am misunderstanding something here with what you are saying. Are you asking for clarification on running in series or primary secondary? I was assuming primary secondary.

OK I reordered some of these so hopefully my goal will be easier to understand. In my current setup with wood boiler in series with oil boiler I have circs for each zone and a circ for the wood boiler. Issue is when the wood boiler circ is running I get ghost flows in my heat zones. I need to solve this for this winter. I cannot afford to add the indirect DHW tank and my storage tank this year (planning for next summer) But whatever I buy to solve the ghost flow issue I want to be able to reuse. Easiest for me this year would be circs with IFCs but will I be able to reuse them in the simple storage design?? Im thinking it may be difficult to get the circuit to allow the oil boiler burner to kick on when there is a call for heat if I use the zone circs instead of zone valves.

So for this one year to take care of the ghost flows I was thinking of putting in the zone valves along with the zone circs so that next summer I could re configure, remove the circulators and just have zone valves. Then re-use one of the circs for the oil boiler, or possibly have to buy one circ with IFC for the oil boiler.

Since you don't have zone valves, there shouldn't need to be 24vac in your system. Your thermostats in the house are hooked to a relay that sends 110vac to the zone pump. You want that same 110vac to the other aquastats. Honeywell aquastats can, and I think usually do, run 110vac through them. I think that is where your confusion is.

Correct no 24v now, just the Honeywell circ controllers which have a small transformer in them. I could power my zone valve per zone circ from these Im thinking. For the wood boiler circ it has 110v going through it. I also have another Honeywell aqustat for overtemp protection and its just got low volt bell wire on it and is wired to the zone motor controller where the thermostat goes.

If you are trying to stop ghost flow with zone valves that does add 24vac into the picture. In that case isolate it from the 110vac using a DPDT relay where the 110 charges the poles to switch it and 24vac actually passes through the relay. This will require a 24vac transformer in your system or pulling power from an existing one if there is one .

This is the setup I am thinking of doing for this winter, but hadnt thought of a DPDT relay, I haven’t done much with relays so was just trying to figure out how to do it with a standard relay which im guessing is a SPST?? Would you mind drawing a diagram of a DPDT relay and how to wire it to do this?? Can you recommend a relay make/model for this function?

When you go to primary secondary hookup I think you would need to add a circ on the oil boiler as the zone circs will pull off of storage unless one is there.

Agreed, if I put just zone valves on the zones that’s what Ill do, but if I keep zone circs then I may put a zone valve on the oil boiler. Allow it to open when wood and storage are cold….

I don't understand this one. In Nofossil's diagram the wood boiler aquastat is hooked up to the wood circ with 110vac. When the wood is hot enough water circs to the zones or storage depending on demand. The tank aquastat should see power when a zone calls to check if it is up to temp. If it is above 140*, the power does not go past that aquastat. If it is below 140*, the power goes on to the oil aquastat and circ.

Thanks I mis-read his diagram I guess. I though he was doing the call circuit with a low voltage contact closures. Doing it with the 110 feed to the oil burner would work too.

Thanks!
~ Phil

 

[WoodNotOil]

That makes so much more sense now! For relay information, see my website in my sig as I use one in my system. It is on the system layout page. Nofossil helped me understand how they work. They can solve a lot of different problems for only a few dollars. Let me know if you have specific questions after looking at it.

 

[Nofossil]

This is great!

I think I can retire now.....

 

[WoodNotOil]

Your not allowed to retire yet! We still have too many questions!

Maybe you can find time to have a few more beers though.

 

[mpilihp]

Thanks guys, nice website too Woodnotoil Ill get a relay to play with. Do they they have relays that operate in reverse? IE apply 120V and activate contacts that can be for 24v??

~ Phil

 

[Nofossil]

Thanks guys, nice website too Woodnotoil Ill get a relay to play with. Do they they have relays that operate in reverse? IE apply 120V and activate contacts that can be for 24v??

~ Phil

When you spec a relay there are three things that matter:

1) Coil. The coil that activates it will be rated for some voltage, and will be either AC or DC. Coose a coil that matches the voltage that you will use. I have in my system 110vac, 220vac, 24vac, and 12vdc coils.

2) Contact configuration. A relay is essentially a switch, but for some reason it's called a 'pole' in relayspeak. A double pole relay is essentially two independent switches that are activated together. The switch can be just a pair of contacts that are connected or not - called 'single throw'. You can also have a switch that has a common contact that can be connected to either of a pair of additional contacts depending on whether the relay is activated - the 'normally closed' (NC) contact if it's not activated, and the 'normally open' (NO) contact if it is. This gets strung together into abbreviations: SPDT is Single Pole Double Throw, and so on. I usually get DPDT relays because they don't cost much more and the second set of contacts often comes in handy - switching an indicator light, for instance.

3) Contact ratings. Contacts are rated for the combination of voltage and current that they can switch. Usually, it's pretty high voltage, and current depends on the mechanical size of the relay. You want something that can handle the device that will be controlled by the relay. Even a tiny relay can usually do 10 amps or more. Relays are often rated a bit lower when switching inductive loads like motors.


Hope this helps.

 

[mpilihp]

Hi thanks yes it does help, but Im curious WoodNotOil, the relay you are using:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=Z787-ND

It says its power is rated at 30VDC and its contacts are rated at 110AC, this to me is saying the INPUT side is for 24v input and it can control 110vac load but your using it with 110v input as well.

I do also see that it states the coil is rated for 120AC... Im confused.

~ Phil

 

[WoodNotOil]

This chart might help clarify things a little http://www.components.omron.com/components/web/webfiles.nsf$FILES/part_compare.html?ID=0CNEN-6TJR6E&NAME=LY2F-AC110/120

I am running 110vac through the whole thing. Generally when you charge the coil that current does not pass through to any other part of the relay. However, in my application note that I put a jumper in to pass the coil ac to the switch from 7 to 5.

 

[Nofossil]

The confusion is that Omron has a family designation: 'Power, Over 2 Amps @ 30 VDC'

This particulat relay has a 120vac coil and contacts rated for 10 amps at 120vac (I guess that would be 'over 2 Amps @ 30 VDC').

To make life much more complicated, people like WoodNotOil routinely use relays to control other relays. It can cause your brain to explode if you're not careful.

It's possible to build very complex logic using only relays. By connecting them in various ways, you can create circuits that implement logic such as 'Turn on this load if A is true and either B or C is true, but not if D is true'.

In fact, you could build an actual computer entirely from relays. I would take a lot of them, though....

 

[mpilihp]

Hi Guys thanks for the suggestions and help, after looking the diagram over closely for the simplest storage solution Ive realized that the way I plumbed mine I cannot have just ONE circ for all my zones. SOOO Im doing it with individual zone circs with IFCs and when I add storage Ill control them with relays that allow me to provide the oil boiler demand circuit. I have until next fall to get that worked out.

~ Phil