Gas and Oil Home Heating Furnaces - Under floor mounted gas heaters

I have recently purchased four small apartments, which were built in 1943. They each have a furnace mounted under the floor, accessible via the basement and crawl space and vented into one floor vent in the living area. I turned off all the thermostats and shut off the gas valve to each once the weather warmed. However I noticed that three out of the four do not have a button/valve which normally has three positions "On, Off, Pilot", or at least I cannot find anything which resembles the button on the fourth. What is this control button/valve called and what do I need to ask for when requesting that a contractor service them? Any other hints, tips or suggestions on dealing with these types of heaters would be most appreciated.

Regards,
Vela

Sounds like your 4th heater is an old one! You still should be able to turn it off.. the shut off will be outside of the unit along with another shut off for the small gas line for the pilot. But being it's that old. I'd maybe look into replacing that one for you and renter's safety in the long run. Also savings.

I would say in the fall when you are ready to start the heaters, remove the grates up in the living area, and clean up all the dirt, and whatnot that may of fallen down the grates.

I apologize, but are you saying that the one WITH the knob that says ON, OFF, PILOT is the old unit or are the three WITHOUT that know the older units? From the outside they all look exactly the same model.

Thanks,
Vela

So you have 4 floor furnaces. Sounds like you can have just one that is newer than the rest and it has a on off pilot on it. I think if you look the others have just a BASO valve on the gas line with a T/C on it this you have to light the pilot and hold down. After it is ok then the main valve will have gas to it and work. If there is no electric to them then they have a Thermopiled or Genertors in them that make the tstat work. AS said do clean out down in them before you turn them on. Also check for code there and see if they can be in a rental unit. You can be in deep deep doodoo if some one steps on them and gets a burn.
Williams company still makes them .

ED ;)

Sounds like you have floor furnaces with 50% safety systems. Meaning the pilot generator is the safety. If the pilot goes out, than the burner will not come on, however the pilot gas continues to escape. These are commonly refer to as " B60" systems. Very very common. Normally these have 2 rods extending up to the top to control the pilot and burner valves. If they don't they have probably been worked on in the past and the rods left off when new controls were installed. Sounds like that is why the 4th furnace has a different gas valve. As you know I am guessing at what you have. I would highly recommend having a dealer or the gas co do a safety check. So much of the time the vents are rusted thru and need attention. Also if any controls have been replaced, the gas input should be clocked and adjusted to rating