rads downstairs lukewarm, upstairs hot

Dale

Sure sounds like one of 2 main vents is ok and the other not, look real close near the boiler return piping for the vent or plug. Perhaps the rad vents upstairs are good and the downstairs ones not, I would take out one of the lower level rad vents rad to check, be safe, steam is hot. If there are 2 return drops to the boiler perhaps one is pretty blocked. Any plug you can remove to check wet return area at bottom of hartford loop? I am assuming no buried wet returns.

Joe H

rads downstairs lukewarm upstairs hot

1920 house( first winter in it ).one pipe steam (gas heat) . thermostat downstairs , radiators typically provide much more output upstairs than down. I have read dans book ( helpful) but cant seem to balance the rads . I have done the following
1 ) pitched all the radiators 2) no main vents as described in Dans book to adjust 3) all pipes well insulated 4)Flush the`low water cut off each week . 5)checked and cleaned radiator vents . Have not installed any TRVs as my guess is this would only regulate the heat on the upstairs rads and do nothing to increase the out put downstairs , any help would be appreciated .

nicholas bonham-carter

main vents

your system definitely needs main vents, and must have had them when first installed. the operation of 1-pipe steam requires the air to be removed from all pipes and radiators before the steam can enter the radiators. the radiator air vents cannot do this job alone; the main vents will do most of the air removal.

examine your pipes once again for any places, now plugged where they were installed originally. they should be close to the end of the dry return at the point where it drops down to meet the boiler [parallel flow system]. if a counterflow system, then toward the end of the mains after the last radiator.

one more factor in this-low pressure no more than 1 psi, and lower if possible make the vents work better.--nbc

Joe H

main vents

nbc : Thanks for the quick reply . I investigated the piping again as you suggest. All the pipes leading from/to the boiler are heavily encapsulated in asbestos insulation. If there are any vents or plugs on these pipes they must be covered up. I also checked the pressure gauge. its set @ 1 psi. I'll try to adjust to .5 psi and see if there is any change.
thanks again

Joe H

main vents

nbc: Just wanted to get back to you w/ my progress in case you were interested. Had a one pipe steam specialist inspect the system today. (he has been to Dons seminars.)He confirmed no main vents anywhere in the piping, nor near the ends of any of the mains(its a counter flow system). He said the system is properly pitched and all the angles at the "t"s are correctly designed . For a cheap fix, he suggested I install adjustable air vents on all the radiators , (right now they are the fixed version) and play w/ those to see if it makes a difference . thanks for your input .

Unknown

pkl- Try swapping one of the "good" upstairs vents with a "bad" downstairs vent. That will give you an indication of whether the downstairs vents are indeed "bad". Do this of course with the system shut off and cooled a bit. Steam gives a nasty burn. Radiator vents can go bad especially if exposed to high pressure (above 3 PSI)

While you can try adjustable vents, you really need to get main vents installed. Maybe the thing to do is try out adjustable vents for now and make the main vents a spring project when things warm up.

The biggest adjustable vent is the Heat Timer Vari-valve.

http://www.heat-timer.com/literature/VariV056082C.pdf

You should be able to get them locally or they are available from Pex Supply:

http://www.pexsupply.com/categories.asp?cID=362&brandid=

Due to their large vent opening they have a tendency to "spit" if opened too much (especially if one has wet steam)so keep an eye out for that.

- Rod

Joe H

main vents

rod : Thanks for the advice. I will do excatly that . Contractor indicated he can put some main vents on the ends if the new vents don't make a difference . Spring project, yes ! Would you suggest adding a TRV like the Danfoss to a Heat-Timer vari valve or is that over kill ?

Unknown

TRVs just control the heat in a hot room by not allowing air to escape the radiator if the room temperature is above the TRV setting. I answered a guy this morning on how TRVs work. Check this thread for more info:

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=61958&mc=4

As the Vari-valve is adjustable, if it gets too hot just adjust the vent to slow the venting down a bit. Let's get you heat first and then we can adjust from there.

Again Be careful of steam. It's invisible and can burn you instantly so make sure things are off and cooled down a bit before removing /replacing a steam vent. Also keep that in mind when adjusting the Vari-valve. You can adjust them when they are working. Just be careful and use a pencil and an oven mitt.

- Rod

Joe H

rads downstairs lukewarm, upstairs hot

Rod : Great feedback . Thanks again . I'll order some of the adjustable air vents and go from there . Thanks for the safety warning as well. It's 1 degree out side today ,so I'll make sure the rads are off and cooled before installing.

Unknown

Before changing a vent, make sure to shut the boiler off, not just the radiators. You never know whether a radiator is leaking or the handle just turns but the supply valve stays open. Unscrewing the radiator vent in this condition can get you a nasty surprise. Don't mean to sound like a safety nut but a steam burn can ruin your whole day! Ask me how I know!

At first reasonable opportunity I'd get the main vent situation looked at. The fact the upstairs works okay and the downstairs doesn't is rather odd as it is usually the other way around.

Let us know how the Vari-Valves work out. Vari-valves at minimum setting, vent probably twice as much as the vents on your radiators now. At maximum setting - 10-20 times more.

You may not need them on all the downstairs radiators - provided each regular vent is working okay. You may only need one on the last radiator (farthest away from the boiler) to let the air escape. I'd start there and see how that works and if more are necessary, add them a radiator at a time progressively back down the main toward the boiler leaving an time interval after each addition to check out how the system is now working. It's not a bad idea to keep a chart of the times it takes for each radiator to heat up as then you can see if any change you make in the system is beneficial.

You mentioned TRVs -Once you get adequate heat to every radiator then if any get too hot you can use a TRV on that single radiator in place of the normal vent. You don't use a vent and a TRV together. Just don't put a TRV in the same room as where the thermostat that controls the boiler is located.

- Rod

nicholas bonham-carter

main vents

i would do the main vent installation before the trv's. the main vents do most of the work in a steam system, with the radiator vents taking care of the air removal in the risers and runouts. if you look at the "balancing steam systems using a venting chart", you will see the great difference between the capacity of a radiator vent, and a main vent. the optimum strategy is to use generous main vents to remove the air from the mains [and boiler], which is a large volume to deal with. the radiator vents are then able to remove the air from the riser and radiator [a much smaller volume].--nbc

Joe H

main vents

nbc : Good advice . my plan is to now get the adjustable air vents for the units and in the spring add the main vents in the piping. My hope is i won't need the trvs for temp control if each radiator is adjustable.