Missing cad cell

hamp215

I have a property that I am renovating. It has oil forced air. The system fired up initially and ran well for a while. Then the second time upon attempting to start it would shut down. I checked and noticed that the furnace had no cad cell. Is it possible that the previous owner somehow bypassed the cad cell. Is this possible. I'm thinking of replacing the transformer, cad cell relay and cad cell

STEVEusaPA

Would need to see a pic.
Pretty hard to bypass a cad cell, either the burner would always run or it wouldn't (shouldn't) turn on.
Maybe the eye was loose and it fell off and is either sitting in the air tube (more likely), or shot into the chamber (less likely).
I wouldn't just replace all the parts if nothing is wrong with them.

HVACNUT

Stack relay? I hope not.
How did it go through a full cycle, and then not?

hamp215

That's whats confusing. The stack relay is present. I don't believe it was a cad cell present there are no wires coming from the relay indicating that a cad cell was present

hamp215

I will take a pic & post it tomorrow. Thanks everyone

STEVEusaPA

Never thought of a stack relay, good call @HVACNUT. Almost never see them anymore.
Well if it's a stack relay, you won't see a cad cell in the burner, the safety is controlled by the ancient stack relay.
You should have that replaced with a modern 15 second cad cell relay primary control.
If there is no place to mount the cad cell (like the transformer) you can use one of the provided clips and connect it to the nozzle line.
You just want to check resistance (ohms) while it's running to make sure you have the alignment and placement correct.

HVACNUT

> @STEVEusaPA said:
> Never thought of a stack relay, good call @HVACNUT. Almost never see them anymore.
>
For some reason, while I was reading the post, I had a 70's flashback. In my vision I also saw layer upon layer of furnace cement.

Steamhead

@hamp215 , make sure you get some pics of the burner.

Big Ed_4

Hmmm ......Wonder if it was a Blueray

hamp215

Trying to send pics

hamp215

Here are more pics

STEVEusaPA

You’re wasting a lot of money up the flue running that burner/furnace.
Compression fitting isn’t helping either.
You’re primary safety is thru the stack relay which at best is a 60 second lockout...could be 90 seconds. That’s 60 seconds of un burnt oil going into the chamber without firing, per reset.
You could pull that out, clean the helix (bimetallic element), reset the control to see if that helps.
But if you have to keep it, a competent tech should properly service that furnace/burner, replace the stack relay with a 15 sec modern primary, replace the compression fittings with flare fittings.
Proper cleaning, proper tune up, check the components, check for vacuum leak, proper bleed, and combustion test are needed.
Or put all that time, effort and money towards a new properly sized, properly installed furnace.

hamp215

I was definitely thinking of switching to a forced air gas furnace. Thanks for the input.

mattmia2

what's with the spring? what happened to the return plenum?
is the supply ductwork graduated?