Best Of
Re: Oil comes out of vent pipe
If you got oil out of the vent it would seem the tank is full. If installed 28 years ago it should have had a whistle. The oil companies carry a portable whistle in there truck a "Scully fast Fill" that they can use but it will not work in an offset fill pipe.
The good news is spring is here because you have some digging to do.
I would dig it up check for a whistle and make sure the vent pipe is pitched so it is low on the tank end. The fill should also be straight with no offset if at all possible
Re: Venting before dropping into a water seal
What we normally do that a lot of our old timers did with the steam buildings we have is we would get rid of both 90's on both sides of the door that go into the floor with tee's. Then you would pipe in up over the door from one tee and reconnect to the other tee. That acts as a cross over vent and as long as the condensate is not trapped again then the boiler feed tank vent does the venting.
Re: Delayed condensate returns
With a system that big, depending on the pipe size of the returns, even with the guts removed from the trap it still may be a restriction.
Re: Is this a house trap?
They either don't know what they are doing or shysters...or both. Mad Dog
Re: Is this a house trap?
Is this cast iron pipe used for rain gutter drainage to a storm sewer or grey water and waste to a sanitary sewer?
What you have there is a cast iron wye with a threaded plug there.

Re: Mitsubishi Minisplit Inverter Board
install a
https://www.icmcontrols.com/product/icm493/
Mitsubishi has some on the best tech support. Have the contractor call them.

Re: Venting before dropping into a water seal
Put the single vent up high where it is far away from the water but a single vent of sufficient size will solve the problem. The air that is in the emitters which is what you need to remove will find the vent as long as all your steam traps are good.,

Re: One pipe steam dry return blockage
Water leaving the boiler while firing is usually liquid water being thrown out of the boiler because of improper near boiler piping or poor water quality.

Re: One pipe steam dry return blockage
Tell us more about the water level.
Where does it start?
How quickly does it drop during a call for heat?
How much does it drop?
How long in minutes after the call for heat ends does the level return?
Re: One pipe steam dry return blockage
Usually the only parts that will really clog are the wet returns. Whatever is in a main extension can usually be flushed out with a hose if some sort of debris gets in there.
Both of those conditions are pretty rare, usually it is an issue with sagging pipe and water trapped somewhere because of the sag or a problem with venting.
