Replacing Main Vents - What to use? Pics inside

BobbyC

I have 2 mains.  Fired my boiler and realized 1 main takes longer to get hot than the other.  Boiler was replaced a few years ago and been wanting to replace the mains been procrasinating.   Hoping i might be able to get better efficiency too.  Heating bills have always been high since I bought this place.   here are the pics.   Thanks alot for your help

BobbyC

Forgot to list length of mains

Measured from where mains tee off right to where current air valve is.

Main 1 - 35 feet

Main 2 - 41 feet

Pipe I believe is 2 inches for mains and near boiler piping is 2.5 inches.

thanks again

BobC

Ventrite 35's are too small

Those two mains contain almost a cubic foot of air each and the vents you have now (Ventrite 35's?) would take over 5 minutes to vent each main. Those vents also should not be at the end of the main because that can expose them to life shortening stress.



I would replace the vents with Gorton #2's and I would move them at least a foot back along that main with a 90 degree elbow, a 12" pipe back along the main (to keep the right pitch), another 90 and a 6" nipple to mount the vent on. the Gortons are a large vent so use a 4" nipple if the 6" is to tight. That will increase the venting dramatically.



The Gorton #2's have a 1/2" thread so you will probably need a 3/4 to 1/2" reduced ontop of that nipple.



Bob

BobbyC

Thanks Bob C

I'm guessing I'll need a pro to install them a foot back or something I can do on my own?  Would I still get better venting if I just replace the ventrite with the Gorton # 2's and leave them in the same spot?

BobbyC

They are ventrite 35's

just took one off

BobbyC

took a look at some pics on the site and catch your drift

Do I do the 90 off the 4" nipple that the ventrites are connected to now?

when should I reduce it from 3/4 to 1/2"?  at the first 90 or closer to the vent 12" back?

I measured out and I got plenty of space for the Gorton # 2.

BobC

Not a bad job for DIY

The problem with mounting the vents right at the t is they can be damaged by water and steam banging back and forth. They should last longer if further away from there.



You can do something like this yourself without to much trouble with parts from the local hardware or big box store, the 3/4 to 1/2' adapter (your existing pipe looks like 3/4") could be just before the air vent or ontop of the existing nipple (do everything else with 1/2" fittings from there. The old vents should come off with a little help from a wrench. Get the Gorton #2's first so you'll know what your dealing with, if you can't find them locally try  - http://www.pexsupply.com/Gorton-G2-Gorton-No-2-Straight-Air-Eliminator-3524000-p



On second look your existing nipple looks like 1/2" on at least one of those vents, check everything before buying the pipe fittings. (the ventrite 35 is 1/2" ID and 3/4" OD). Don't try to use the Gorton body to tighten up the vent, use a wrench.



Bob

BobbyC

Perfect

Thanks Bob.  Gonna order the Gortons and go from there.   Does the venting suffer at all the farther away from main pipe it is?

Also, will it vent better if I use 3/4" and then reduce right at the Gorton or will I notice any performance difference reducing to 1/2" at the T and using 1/2" the rest of the way?   I know it's a minor detail but figure I'd ask and do it the way you recommend.

Thanks again for guidance. 

BobC

1/2" pipe?

Tony,



As long as you have enough vent capacity to vent the main fast it doesn't make a lot difference how long the main is. On longer mains it takes longer for everything to get hot because you have to get all that iron up to steam temperature, insulation really helps shorten that time.



If the nipple on the existing valve is 3/4" you might want to put the reducer right before the nipple IF there is a possibility you will need to install more than 2ea Gorton #2 at that location. An open 1/2"pipe will vent 3.4 CFM at 2oz (a 3/4" pipe probably a bit more than twice that but I'd have to dig a bit to prove it) and a Gorton #2 is rated for 1.75 cfm at 2 oz so two of them would be able to vent at pretty close to their full rate (2X1.75=3.5). I got that info from Greening Steam



With about 40 Ft of main on each main you should be ok with a single #2 at each location and a 1/2' pipe will let you use two each Gorton #2's if need be. As i said it looks like at least one of your vents is on a 1/2" pipe, if that is true I'd just pipe it all in 1/2' pipe.



Bob

BobbyC

Both nipples are 3/4"

so i guess I'll just reduce them both to 1/2" at the 90 before the second nipple and put the Groton at the top of that 1/2" second nipple.  

hopefully that does the trick. 

Thanks

crash2009

Ventrite # 35

is 3/4" male on the outside, and 1/2" female on the inside.  http://www.macwilliamsupply.com/vent-rite-35-air-elimination-steam-vents-air-valve-no-35.html  This makes your existing nipple 1/2".  Use black iron for the fittings.  The union will allow easy removal in the future.  (for cleaning or upgrade)  Two Gorton 2's is the max on a 1/2" pipe.  Here is a picture of an antler I put together a couple years ago.  I copied this diagram drawn by Brad White.

BobbyC

Crash, that's the one.

So the nipple is 1/2".  

Should I use the existing nipple and pipe it all in 1/2"?

How far back after the 90 should I put the Gorton?  12" like Bob C recommends?  Thanks for the pics.   Gonna try and duplicate that set up with the Gorton 2's.  

crash2009

I really can't tell from here,

 but if the nipple fits inside the Ventrite 35, it has to be 1/2".  I'd use the existing 1/2" nipple, then a union, then another nipple 2" or 3" or 4" (you will have to figure that out, looks like you have a floor joist to watch out for), then your 90, then a 9"-12" nipple like Bob recomends (depends on the floor joist), then your T, and a couple 1/2" plugs (one for the end of the T, and a spare)



By the way, if you look real close on that fitting that is painted black, it will be stamped what size all three of those pipes are (2 X 2 X 1/2?)

BobbyC

Thanks Chris

It's 1/2 inch.  I'll follow you and Bob's direction and looking forward to faster venting soon.  Gonna insulate near boiler piping too and any other pipe exposed in basement without insulation.

thanks for your help guys....

BobbyC

New Mains vents on - Pic - look ok?

Put the new mains on the antler from your guidance.  Wanted to share a pic and make sure all looks good.

thanks fellas

Dave in QCA

Looks Great

Nice job on the install!  Should make your system run better with more even distribution of the steam.

BobC

Good job

That should work out fine, you can easily add more venting if you have to.



I tuned my boiler on for the first heat run of the year. The house was at 63 and I set the tstat to 65 (the boiler was stone cold and I'm using a Honeywell RTD 6350 tstat), I timed everything from the start (minutes : seconds) -



0:00    tstat on

06:10  steam at boiler output

09:35  main vent hot 0.05PSI on 0 - 3 PSI gauge

10:54  0.2PSI

16:26  0.4PSI

17:10  0.75PSI vaporstat off

17:59  0.30PSI vaporstat on

19:12  0.75PSI vaporstat off

~~~~

30:54  tstat off



My 2" main is only about 12 ft long and the avg radiator leader is about 16 ft long (2 story house) This cycling continued for 6 more cycles til the thermostat was satisfied, at the end the on to off time was about one minute on and one minute off. I notice the pressure gauge goes up to 0.2PSI and then drops drops below 0.1PSI for a couple of minutes before building again and I'm really not sure why.



Those numbers are the curse of having a steam boiler that is rated at 596 sq of steam and an EDR of 190 Sq feet. I've downfired the oil burner to 1.1GPH and that is about as far as i dare go. I will switch to gas when it's time but I don't want to go with an atmospheric boiler. When I replace it I'll  go with a Smith G8 with a gas gun; it will still be overfired but not nearly as bad as it is now.



Good luck with the new vents,



Bob

BobbyC

thanks

Thanks for help guys.  Hopefully it saves me some dough.  next up is to insulate the house cause I know that is my biggest culprit. 

BobbyC

How long should the mains take to get hot.

guys,

Installed the Gorton 2's and trying to decide if I need more main venting.  How long should it take the mains to get completely hot from the time the boiler starts making steam?  I saw 1 min in a post and not sure if that is the norm. 

Timed mine and one was around 3 mins and the other about 20 -30 seconds after.  

BobC

Should be ok

When you consider that all that iron pipe has to come up to temperature 3 minutes should be fine. In my opinion adding more venting would not hurt but I don't think it would be worth the added cost.



Better to spend that $$ on insulation.



Bob

BobbyC

Insulation

Thanks Bob.  Did some insulation of near boiling piping but still need to finish with some pieces for the 90's. t's etc...