Coal Primary- Oil Secondary Automatic Failover Project

I worked this out last year and plan to try it out this year.

I'm planning on building an integrated box with the controls and LEDs to visually indicate the current mode of operation at a glance.

Anyone see any gotchas?

FYI. I copyright the design to protect it. No commercial use without permission. If you want to use it for your own personal use, permission granted

UM, the Hydrostat 3250 Plus, I think they beat you to it.
And with a simple 2 position switch to divert power
from the coal circiut to the oil circuit.

lzaharis wrote:UM, the Hydrostat 3250 Plus, I think they beat you to it.
And with a simple 2 position switch to divert power
from the coal circiut to the oil circuit.

I googled that, but didn't see what you are mentioning?

I did find a unit that adjusts boiler temp and such. Maybe that is a multi-purpose device?

Maybe I just missed it, Got a link?

I've wanted to set something like this up, but it would have to be much simpler ... or else I'll never do it.

I'm thinking a snap switch connected to a relay - temp falls, switch closes, oil burner fires. That would at least float me along until I had time to get down there to fix whatever caused the coal fire outage.

SMITTY wrote:I've wanted to set something like this up, but it would have to be much simpler ... or else I'll never do it.

I'm thinking a snap switch connected to a relay - temp falls, switch closes, oil burner fires. That would at least float me along until I had time to get down there to fix whatever caused the coal fire outage.

That's how it started, then I added two things.

1. Switch to bypass the "auto" setting
2. Fire out and hold-to-light

That required me to reverse the circuit to make it a normally open where it was normally closed, etc.

Then I added relays so it could switch AC or DC of whatever voltage. Simply use a relay suited for the trigger and the line voltage/amps needed.

Oh- and I wanted to have it use LEDs to visually show what "mode" it was running in so a non-NEPA user (ie my wife, or someone watching the house) could tell at a glance what it was doing and "how" to switch it.

When I get a bit of time, I'll put together another version (each one has some component changes for both cost and function) and take some pics. It won't be right away, lots to fit into that "bit o' time" slot LOL

CoalisCoolxWarm wrote:

lzaharis wrote:UM, the Hydrostat 3250 Plus, I think they beat you to it.
And with a simple 2 position switch to divert power
from the coal circuit to the oil circuit.

I googled that, but didn't see what you are mentioning?

I did find a unit that adjusts boiler temp and such. Maybe that is a multi-purpose device?

Maybe I just missed it, Got a link?

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Use two Hydrostat 3250 plus units, one for oil and one for the coal boiler, they are not that expensive to buy or own as they are solid state devices with thermowell mounts as standard equipment.

http://www.hydrolevel.com

lzaharis wrote:Use two Hydrostat 3250 plus units, one for oil and one for the coal boiler, they are not that expensive to buy or own as they are solid state devices with thermowell mounts as standard equipment.

http://www.hydrolevel.com

Okay, they are something like $175/each and "take over" each system, right? Probably do much more than my thoughts above.

My solution is probably in the $75 range and works with only the power circuit and TT, so no rewiring or other major control changes necessary.

I don't know the hydrolevel system, but it looks to be much more involved than I intended to get

I do appreciate the link, though. Always looking to learn

I have installed 3250's on a few different systems and they are basically a "fancy" triple aquastat with a low water cutoff function. They are not a plug and play solution for all of the things you have listed in your diagram. Your relay solution is cheap and effective, nice work.