Vari-Valve spitting water

kevinm1024

I have a one pipe steam system, I'm looking to replace the vents. I bought a couple Vari-Valve vents but I've been having trouble with them spitting water. I made sure the radiator's pitched back towards the shutoff so it would drain back. I have also tried the vent with the white dial on the bottom (Vent-Rite I think?) and I've noticed they have a small brass insert inside the threads of the valve to keep the water from coming out (I think.) Anyone else have this problem with Vari-Valves?



Another question:

I have two loops off the steam header for right and left sides of my house. There are no main line vents, which I've read I should probably add. I read they should be 12" before the end of the main line, but I'm unclear where you would consider the end of the main line and the start of the condensate return line. There are 4 radiators on each of the loops (total 8) but 1 radiator is shut off on each of the lines, so only 6 are "active."



And another:

I think according to <a href="http://www.comfort-calc.net/Steam_Piping_Donts.html">http://www.comfort-calc.net/Steam_Piping_Donts.html</a> that the T on my main line is incorrect, am I correct? I'm not sure how clear this picture is, in the foreground closer to the top of the picture is the two main lines. The background is the return lines.



Thanks for any help you can give!

jpf321

piping and pressure

Yes, your piping is wacky...beginning between the boiler and the overhead mains, it should no be a straight run to the mains, any water dropping out is being carried vertically or collapsing your steam. The mains should be taken off a horizontal "header". Study all those great pics at the site you linked.



No vents shouldn't spit...what is your pressure control set at? Do you have a reliable low pressure gauge instlled?



Between your piping and pressure you could probably do a better job of prodcucing dry steam.

crash2009

need more pics

Need more pictures Kevin.  We cant see behind the boiler.  I did a little sketch for ya to help you visualise the how the comfort-calc pictures apply to what you have.  Normaly the main vents are around 15" from the drop.  Whether or not you need all that stuff I have no idea.  It is very likely that you have some sort of openings in your main line, now covered with insulation.  The main vent hole should be somewhere between the last radiator and the drop down to the boiler, if not right at the drop itself.

kevinm1024

Thanks!

Thanks for the great help so far! Here is another picture from the back. Would it be better for the main vents to be near the boiler just before the returns drop down or to have them out near where the last radiator of the loop goes up? For instance in the second picture here, the last radiator is on the section of pipe farthest away (the 3' one before it starts coming back.)



Pressure is .5 cut in and 1 cut out. I do not have a good pressure gauge, it goes up to like 40PSI. It can't really pick up on 1 PSI.

crash2009

Need another pic.

 Can you show the yellow arrow higher up? 

jpf321

vent placement quandry...

it's a good question that I have been trying to work through .. what are the pros and cons of vent placement provided they are at least past the last rad riser ...



in theory you don't necessarily want to fill the "extra" main pipes since you would be losing heat and adding pick-up factor. the condensate WILL go where air is, so that's not an issue. placing the rads near the last rad riser also allows you to come to pressure earlier and therefore decreases burn time.



i'd love to hear the opinions of others.



i think in general dead men designed systems that didn't have this as a problem necessarily and were able to place vents between last rad and drop to wet return without a significant amount of leftover overhead piping. i think I remember reading that it was during the "conversion to oil" era that "single loop main systems" were split into 2 separate loops that many of us now have.



in my system, i have a split loop (front and back) which both drop past their last rad almost immediately to a common wet return. i had little choice in vent placement, and just barely enough room between the last rad and the elbow which drops wet.

Big-Al_2

They do spit, even with a properly piped system.

No doubt, your near boiler piping is a mess and that is probably producing wet steam . . . however . . . in my experience, Varivalves often spit anyway.  In most vents, the vent hole is on the top and the mechanism that closes the hole works up from the bottom.  During any fairly long heating cycle, some steam is going to condense in the body of the vent itself.  When the vent cools and re-opens, most of the water drains back into the radiator, and the next time the vent vents, the little bit of water left behind just sits in the bottom of the vent. 

With a Varivalve, the opening is on the side and the thermostatic bellows comes down from the top.  Any condensate that forms in the vent basically just sits on a shelf inside the vent and doesn't drain back all that well.  When the boiler cycles the next time, even before the steam reaches the radiator, just the air escaping from the vent is enough to push out whatever water was left in the vent from the last cycle . . . Haaachhh . . . tooohey.  It spits. 

I have one radiator in my house in a cold upstairs room that I want to heat up really fast.  I use a Varivalve there, and it sometimes spits out a teaspoon of water or so . . . so I keep a small sheet of plexiglass under the vent.  It hardly shows and it protects the hardwood floor.  I've tried Varivalves in other rooms too, but went back to more conventional units to avoid having the radiator loogie on the floor.

kevinm1024

wet steam

About 1 foot after my last radiator tee's off the pipe reduces to 1", so I'm thinking the main line vent should be between the last radiator and where the pipe reduces?



Correction on steam pressure: It's .5 cut-in and 1 differential, so I believe that is 1.5 cut-out, correct?



Crash2009: Here is a better picture of the return lines.



Big-Al:  Good to know I'm not the only one with trouble from vari-valves.



Thanks!

crash2009

Finding the main vent tappings

 I have heard that in the past some people removed the vents for spitting on the ceiling, and plugged the hole.  Your joists are painted, is there any rusty spit markings between the last rad and the boiler?  Sometimes the vents are put where I circled in this picture.

kevinm1024

main vents

I'm assuming the hole would be in a fitting and not just in a section of pipe, correct? I felt around for anything, but a 1/4" hole with a plug in it is smaller then what I was trying to find. I may have missed something.



Any other obvious problems with the piping besides the T above the header on the mains?

crash2009

Which rads are shut off?

I was looking for a bigger hole than 1/8, maybe 1/2or 3/4.  And yes I was thinking it was in a fitting.  Maybe they vented this one through the last radiator.  Which rads are shut off? 

nicholas bonham-carter

main vent location

those unions could enable the main vent placement on the vertical pipes of the returns, above the waterline. then you wouldn't have to bother with the tiny boxed in opening. one of those radiator vents in place looks like an early hoffman vacuum vent.--nbc

Charlie from wmass

Often less than ideal installs

used radiator vents as many line vents. That 1/4" maybe what they used.

Long Beach Ed

Don't Worry

Don't worry, they will stop spitting in about six months. 



The bellows in every one will detach inside the Vari-Vents and they'll stay closed all the time.



Seriously.  two thirds of two hundred we installed on a job died within a year and Heattimer wouldn't even answer out Certified Mail correspondence. 



Other than that, these tend to be very fast vents which are helpful when you have no main vents but tend to spit water when your steam is wet.  You have two choices here.  Either re-pipe that boiler correctly so that the steam is dryer, which will save you lots of fuel, or install slower vents, like smaller Gorton's on the spitting radiators. 



A slower vented radiator will produce condensation slower, giving more time for drainage.   The slower venting will decrease steam velocity,  allowing better radiator drainage and checking the tendency to blow water out of the vents.  This will also cost you more money in fuel as you are holding back the steam. 



When a system is piped poorly, these are the trade-offs that you must make...  either correct the problems, live with the problems or settle for certain inefficiencies. 

Long Beach Ed

Don't Worry

Don't worry, they will stop spitting in about six months. 



The bellows in every one will detach inside the Vari-Vents and they'll stay closed all the time.



Seriously.  two thirds of two hundred we installed on a job died within a year and Heattimer wouldn't even answer out Certified Mail correspondence. 



Other than that, these tend to be very fast vents which are helpful when you have no main vents but tend to spit water when your steam is wet.  You have two choices here.  Either re-pipe that boiler correctly so that the steam is dryer, which will save you lots of fuel, or install slower vents, like smaller Gorton's on the spitting radiators. 



A slower vented radiator will produce condensation slower, giving more time for drainage.   The slower venting will decrease steam velocity,  allowing better radiator drainage and checking the tendency to blow water out of the vents.  This will also cost you more money in fuel as you are holding back the steam. 



When a system is piped poorly, these are the trade-offs that you must make...  either correct the problems, live with the problems or settle for certain inefficiencies. 

kevinm1024

Vent-Rite #1 then?

The 2nd to last on one loop and 3rd to last on the other are the ones that are off. If I can't find an existing blocked vent, would you think I'd be better to do main vents where you highlighted in the picture or closer to the last radiator branch?

crash2009

slower vents

If you cant find a tapping in the main, I think I would run with what Long  Beach Ed said. 

Install slower vents, like smaller Gorton's on the spitting radiators."  and plan for a re-pipe in the spring

kevinm1024

Thanks again

For all of the help and advice.



1 last question:  One of the radiators that is off is in what is now a three season room. the steam pipe runs for about 6" in an unheated crawl space and then up to the radiator in the unheated room. The valve is off, but I still wonder if I'm losing any heat? Or would the trapped air create an effective stop? Obviously any leaking past the valve is a concern also. I'm thinking about capping the branch on the main when I do the rest of the re-piping.

Dave in QCA

air will keep the steam out

As long as the radiator is shut off tightly, the air will be stuck in the pipe, not steam will enter the pipe, and there is no chance of losing heat.