Stack controls

Ken C.

As I understand them, stack-mounted primary controls on oil systems rely on thermal expansion/contraction to make/break electrical contacts. When I first started plumbing a few years ago, I owned a house with an oil-fired furnace. Sometimes, the furnace wouldn't work. Not having any knowledge of heating at the time, I discovered that I could get the burner to come on again by banging on the smoke pipe. I had an acquaintance who is an experienced oil guy look at it, and he got rid of the stack control and replaced it with a primary control mounted on the burner, and a cad cell eye. Problem solved. This same person is the one who is currently training me on servicing oil equipment. Today, we did another such conversion on a boiler (I did the wiring, he supervised). My questions are: If you encounter a boiler or furnace still using a stack control, do you automatically recommend that the customer change to an electronic primary control? Are stack controls trouble-prone?

J.C.A._3

No!

We do NOT recommend replacement of stack relays, we INSIST ON IT !!!

90+ second relay lockout times come highly UNRECOMMENDED from someone like me, who's lost his eyebrows a few times.
These things are a menace to the oil industry. The people who insist that they are "fine", are a couple frenchfries short of a happy meal. Go NEW!!!!! 5 second lockout times, after flame proving are a bit nicer, and in the long run, CHEAPER!!!!(didn't your mentor teach you the magic word? I'm NOT kidding)

Look at the wiring on about every stack relay you replace. My "educated guess" is that about 1/3 or less, are using the #4 terminal, which drops out the ignition after the bi-metal arm has moved "far enough, but not too far"to tell the burner that it's ok to stay running.

This goes back to aincient Egypt, and is a JOKE, compared to the fine controls available to the market today.

Move forward, save yourself some body hair and get rid of these beasts. As usual, this is JMHO. I may be wrong, but I'll bet money that you'll get the same responses from "seasoned TECHS.". Chris

Bill Nye

I would have

made a comment but JCA summed it up. My feelings exactly.

I had one that blew the door off an old steamer missing the owners head by inches!

Firedragon_4

In Massachusetts we are

only allowed to replace an existing one. With EVERY new burner it must go to a 45 second safety and that ends the debate. However, if blue-flames (low NOX) do make it to the street the Sub-committee did leave the door open for new technology, cool!

Weezbo

They were nice to have in thier day.....

These were nice to have a few decades ago:) Taken out:) hear me?...that stack even if its triple wall should be kicked to the curb Too:)