Vapor system question

Joe Grosso

I went to a job today with a boiler feed tank and f&t traps on all the return line.Also traps on all the radiators in the home.I believe I am looking at a vapor system but the company that was servicing the home has a p 404a pressuretrol on the job.The problem is the third floor radiators are not getting any heat.I believe if I change to a vapor stat I will remedy the problem.All the traps are working fine as are the air vents in the system.I hope i explained the problem I am having properly to you guys and would appreciate any feed back.

Unknown

I think you're on the right track

I'm not sure it will deliver steam up to those radiators, for sure. If not, I'd compare pipe size to the load size on that loop, and I'd look for bare pipe on that run.

Another trick is to see if air or steam is pressurizing the returns. I've gone to the last radiator on the main, shut off it's inlet valve, and pulled the trap cover off. If air or steam blows back at you from the return, there is a trap problem somewhere on that return.

If no pressure is there, open the valve a little to see if the radiator starts to vent it's air out that open trap.

At least you will know if it is a lack of supply or a back pressure in the returns problem.

Noel

keith

nice tip

thanks for the tip on checking for a steam in places it doesn't belong.

Steamhead

F&T traps on Returns?

Doesn't sound right- they should be at the ends of the steam mains, but not between the return line and the pump. The radiator traps keep the steam out of the return (when theyre working that is).

And speaking of that pump- if this is an old Vapor system, is the pump really needed?

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Joe Grosso

Steamhead

I mis spoke. The f&t traps are at the end of the steam mains. Also I do not know if the pump is really needed.I am not sure here but I am not getting any heat up on the third floor of this old home .

Scott2000

vapor/vacuum system

I just came from a house that has hoffman #2-A vacuum air vents on "most" of the radiators. Two pipe steam, No steam traps anywhere, no vacuum pumps, and all dry returns. The owners just moved in over the summer. The vapor stat was changed to a p404a and the system was set to shut down at 5psi...I lowered that to 2 (dif. @ 1/2 and cut in at 1 1/2) I can only assume that the vacuum vents are over 25yrs old. Can vapor/vacuum vent still be purchased? Also, he's got an old 1750rpm oil burner, and wants to upgrade to a 3450rpm. Will this cause the system to heat too fast? The boiler is a beast, but it's well insulated and no leaks so far, he'd like it to last a few years at least before changing the boiler.

Steamhead

Two-pipe Steam with Dry Returns

shouldn't have vents on the rads. The air vents into the dry return thru a trap, or past a water seal (may be hidden in the return bushing or return ell) or there may be an orifice at the supply connection to limit the amount of incoming steam to what the rad can condense. However it gets into the dry return, the air vents out thru a large vent, usually installed in the boiler room at the end of the dry return.

Look at the end of that dry return- I'll bet you find a plugged tee where the vent used to be.

The only exception would be if the system has shutoff valves at both the supply and return connections to each rad. But these systems (at least the ones I've seen) usually have wet returns only, not dry ones.

Changing the oil burner from an old one to a flame-retention one usually involves putting a smaller nozzle in the new burner. This is because flame-retention burners produce hotter flames, and results in better fuel economy. Check with the burner maker or rep for specifics on the burner you will use.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"