3 way valves,4 way valves and the danfoss valve

[cvanhat]

dosnt the danfoss valve supposed to make sure that the water returning to the boiler is warm enough?? if you use the danfoss do you still need the 3 or 4 way, or is the 3/4 way just a cheaper way to replace the danfoss. or am i a complete idiot

 

[Nofossil]

dosnt the danfoss valve supposed to make sure that the water returning to the boiler is warm enough?? if you use the danfoss do you still need the 3 or 4 way, or is the 3/4 way just a cheaper way to replace the danfoss. or am i a complete idiot

I think we need to consider all of these as independent hypotheses ;-)

I believe that in the application you're thinking of, they are all different ways of accomplishing boiler return temperature protection. You can add to that list a bypass loop with either a zone valve or a small circulator.

 

[cvanhat]

now i am confused!! so basically if i put in a three way or a 4 way i dont really need a danfoss. i need a schematic i guess. i am installing a eko 60 along with a 500 gallon storage tank in the same room off of the back of a garage. i then need to tie into my existing oil boiler which is located in the cellar about 60 feet from the eko. i was going to tie in to the tank with a loop back to the eko. and then pull off the tnk and circulate to the oil boiler. does this sound right??

 

[Nofossil]

Without a diagram, I'm not exactly sure what you're referring to. Here's a plumbing diagram that I did a while back for someone looking at a remote boiler / storage setup. Don't know if it will help, but at least it's an approach.

The 'input protection mixing valve' could be a Danfos thermostatic mixing valve or a 3-way that controls output temperature. In my case, I have a simple zone valve in the bypass loop (thin red line) and a tee where the mixing valve is on the diagram.

 

[cvanhat]

the diagram makes sence to me. the wood corculator pump would br running at all times , the load circulator will run at what times?? then you have a third circulator pump that would already be an existing on the oil boiler, so you have basically bypassed the oil boiler all together. most peolpe i have talked to want the eko hot water going into the oil boiler. does it matter which way it is done?? by your diagram it would sem that the oil boiler would be just shut off completly instead of a backup source. the other thing i need to decide is weather to go with zone valves. as the oil boler is set upnow, there are two circulator pumps( 1 for each floor) and the system is either all on or all off. how do you control zone valves, i would guess each zone wood have its own thermostat and would turn on and off as needed. thanks for the help in advance!!

 

[Nofossil]

the diagram makes sence to me. the wood corculator pump would br running at all times , the load circulator will run at what times?? then you have a third circulator pump that would already be an existing on the oil boiler, so you have basically bypassed the oil boiler all together. most peolpe i have talked to want the eko hot water going into the oil boiler. does it matter which way it is done?? by your diagram it would sem that the oil boiler would be just shut off completly instead of a backup source. the other thing i need to decide is weather to go with zone valves. as the oil boler is set upnow, there are two circulator pumps( 1 for each floor) and the system is either all on or all off. how do you control zone valves, i would guess each zone wood have its own thermostat and would turn on and off as needed. thanks for the help in advance!!

This is basically the system I describe in the 'simplest pressurized storage' sticky at the top of the boiler room page.

Load circulator runs whenever there's demand from any zone.

Wood circulator runs if the wood boiler is hot enough.

Oil circulator runs if the oil boiler is hot enough.

There's no circulation through the oil boiler unless it's running. It provides backup - it turns on if there is a demand for heat and the storage is cold.

Zone valves are designed to be controlled by thermostats.

 

[cvanhat]

thanks nofossil, your a great help. i take it that the small box in your diagram between the exp tank and the storage is a check valve. also what size piping do you recommend that is the small red line that runs into the mixing valve? i am planning on 1-1/2 piping for the eko 60 to storage tanks, and 1-1/4 from the tanks into the house which will match the rest of the heating system. now i just have to figure out weather i will be able to install zone valves or just leave the circulators in place that are existing. thanks again!

 

[Nofossil]

thanks nofossil, your a great help. i take it that the small box in your diagram between the exp tank and the storage is a check valve. also what size piping do you recommend that is the small red line that runs into the mixing valve? i am planning on 1-1/2 piping for the eko 60 to storage tanks, and 1-1/4 from the tanks into the house which will match the rest of the heating system. now i just have to figure out weather i will be able to install zone valves or just leave the circulators in place that are existing. thanks again!

The small box is actually an air trap, but there's been some discussion about the wisdom of adding a spring type check valve in the same area to prevent the load circulator from drawing water through the dormant boiler(s) when heat is being drawn from storage. The integral flow checks in most circulators don't present much resistance to passive forward flow.

You'd want an air trap for the oil boiler as well.

By the way, in the remote storage version of this schematic, the load circulator probably should have an integral check valve as well. In this version, the load circulator is not needed when heating with oil.

You don't need a lot of flow and the path is really short, so 3/4" should be fine for the bypass loop.