Last radiator on the line is cold to luke warm

mercedes

Boiler was install before the new owner moved in (25 yrs ago) and the last room was always cold.
Install the main vent valves correctly and calculated and air in the main is vented and steam around 3.5 to 4 minutes
Size each radiator vent valves accordingly to there size ( aero convector radiators) total EDR 292 Boiler cap. 440 sq.
Still the last radiator on the main pipe the riser is also luke warm
try adding several vent valves for faster bleeding of the air no change.
Wondering if the near piping on the Weil Mclain E6 boiler is causing my last radiator to be luke warm?
See attach photo

nicholas bonham-carter

Yes, you are right, and the supply piping needs to be repiped (look at the manual of installation).
You may also have a problem with inadequate (not nonexistent) main vents.--NBC

BobC

Having the two system steam main supply pipes BETWEEN the boiler outlets is bad practice, the system supply pipes should be between the last boiler outlet and the equalizer. What you have now is not making dry steam and that hurts system efficiency.

Make sure the piping that supplies the last radiator has good slope, if water can pool in that pipe it will collapse the steam before it can reach the radiator.

What pressure are you running the system at?

You might try reducing the venting on all the other radiators (especially the one near the thermostat) to see if that gets steam to this radiator. It's best to vent the mains fast and the radiators slowly. What are you using for radiator vents?

Bob

mercedes

Bob

Will recheck the slope of the last radiator piping from the main pipe this morning
running at 1.5 psi cutout
cut in .5
I am using Dan Holohan "Greening Steam" chapter 6 venting practice and using gorton valves #4 and #5, main vent 2 #2
Before last winter 2013 I changed the vent valve and the rooms got more uniform in heat but the last radiator is still luke warm.
Will do near piping but trying to calculate some room as they built very tight to the boiler area.

Thank you for your help.
Dan

BobC

If you can get someone to help you try this test. Remove the vent from that problem radiator. Set the thermostat well up so it won't turn things off quickly and have some stand next to the boiler ready to kill it's power if steam starts to come out of the vent tapping..

See if the radiator gets hot and if not how close the steam gets to that radiator.

If it never gets hot you are either collapsing steam at a furious rate or maybe the radiator valve is broken and the valve is stopping the steam flow. If air is being trapped by a blockage the steam will never flow beyond it.

Also do both mains seem to be heating up at about the same rate?

Bob

BobC

If you can get someone to help you try this test. Remove the vent from that problem radiator. Set the thermostat well up so it won't turn things off quickly and have some stand next to the boiler ready to kill it's power if steam starts to come out of the vent tapping..

See if the radiator gets hot and if not how close the steam gets to that radiator.

If it never gets hot you are either collapsing steam at a furious rate or maybe the radiator valve is broken and the valve is stopping the steam flow. If air is being trapped by a blockage the steam will never flow beyond it.

Also do both mains seem to be heating up at about the same rate?

Bob

mercedes

Bob

I will try this method. Will tell you of the results. I never thought about the steam valve for the radiator maybe internally the valve is partially closed. Good idea. Will follow the steam heat and how far it goes.

thanks
Dan