Replacing old expansion tank

jgaudet

Thank you I will read that!  Also my wood boiler btu is 70,000 and the supply and return 1 inch lines are about 50 feet each running to the oil boiler in the basement. And then the oil boiler is 174,000 btu and it has 1-1/4 iron pipe coming off it only about 2 feet of it. And for my zones 2 of them are 3/4 inch and the longest run is about 80 feet and the other is about 50 and then the other 2 zones are only half inch and one of them is about 40 feet and the other is about 50!  Also the section where one zone is piped off the other is being changed also.

psb75

The oil boiler (and the wood boiler too) will both lose some heat up their stacks if they are heating (or are heated). No way around that. But the wood boiler will burn most efficiently if it is firing at a higher burn rate.
By the way, is there a HEAT DUMP available for the wood boiler IN CASE of POWER DOWN situation--when the boiler can't circulate in a high fire condition? If not...there SHOULD be.

jgaudet

@psb75 in this picture where I circled is my garage zone it has 2 zone valves on it I'm guessing one of them is normally open? And it goes to a beacon/Morris Fan heater in my garage.

jgaudet

@EdTheHeaterMan sorry for all the questions im just back and forth on what to do with my system. i have decided not to go primary secondary because its a little more work than i can do myself and i would need a third circulator and get an electrician here! so i edited this picture a little bit and this is how i would be comfortable doing the system myself. will this setup work? my tank is a #90 14 gallon! also should i add another tank before the circulator beside my wood boiler? or is the one where it is in the system good enough? and the only difference from the picture is my zone valves will be on the supply not the return. thanks again!

EdTheHeaterMan

Yes that should be fine.

The electrical control logic is simple here. Run the system circulator only when there is a call for heat. Run only the wood boiler circulator only when there is heat in the wood boiler. If there is no call for heat but the wood stove still has heat, the oil boiler will be able to be used as a buffer tank to store that heat by operating the wood stove circulator, even if the system circulator is off.

In order to keep the oil burner from operating when the wood stove has heat to use in the house, place a strap on aquastat on wood stove supply outlet in series with the oil burner circuit between the high limit and the L1 or the Limit input on the primary control (the black wire on the three wire primary control). You might set that t about 135° or 140°. Then when the wood stove is running out of heat, the oil burner will operate on a call for heat automatically.

To keep the woodstove from being heated by the oil burner set the woodstove aquastat to stop the woodstove circulator at about 5° cooler than the above mentioned strap on aquastat on the woodstove (oil burner circuit). You shall also add an isolation relay in series with the woodstove circulator circuit to break the woodstove circulator circuit whenever the oil burner is operating. This way the oil burner will not be wasting energy heating the woodstove.

EdTheHeaterMan

Here is a wiring diagram that will facilitate the logic or sequence of operation that i believe will work best. you will need to add a L6006C strap on aquastat and an isolation relay like the RIB relay.


https://www.supplyhouse.com/Resideo-L6006C1018-High-or-Low-Limit-Circulator-Strap-On-Aquastat-65-200-DegreeF-range-5-30-DegreeF-Adj-Differential?msclkid=3cd0587e42fb1ab084ab391f4626214a

https://www.supplyhouse.com/Functional-Devices-RIBU1C-Enclosed-Pilot-Relay-10-Amp-SPDT-w-10-30-Vac-DC-120-Vac-Coil

If you Have Questions on the wiring Logic, or if you have different controls than i have selected, you can send me a message on this forum Just click on my picture to get to my profile and select message.

Yours Truly
Mr.Ed