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Water pushing out air vents on condensate return lines

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Comments

  • waterjet
    waterjet Member Posts: 53
    Fred said:

    I wouldn't do it. Short cycling will occur, Extra wear and tear on the boiler gas value, probably will require you to try to rebalance the remaining radiators, maybe even put smaller vents on them to slow the steam down so those rooms won't get too hot. That may add yet another layer of added pressure . Maybe you should look into a two stage gas valve and fire on the lower stage, if that option can be done on your boiler. I don't know how long it would take to recover the cost but I'd rather see you do something by design than do something and see what happens (especially when you know what will happen isn't likely to be all that good).

    Fred,

    What wouldn't you do? Open the valves part way?

    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    I wouldn't shut those radiators down. Even leaving them cracked is problematic. Steam will still push into them, just have to push harder, kinda like trying to move steam through a section of pipe that is way smaller than it should be.
    waterjet
  • waterjet
    waterjet Member Posts: 53
    Ok, so better to have them open the whole way, than even half way.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    At half way, they will heat as if they were open, just a little more pressure to get past that bottleneck. I'd leave them open all the way if it were me.
    waterjet
  • waterjet
    waterjet Member Posts: 53
    edited December 2014
    I guess one might be ok, but three is probably way too many on such a small system. I was afraid that I might be wasting heat. Would it still be unwise to keep just one of them closed down?
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    You probably can get by shutting one off. At least it is reasonable to try one. If you see problems like higher pressures or more short cycling, open it back up and see if that resolves the problem.
    waterjet
  • waterjet
    waterjet Member Posts: 53
    edited December 2014
    Thanks Fred, I'll test it out. I'm going to open all of them and only close the doors on the spare rooms, that way they can serve as a buffer from the cold and the system can work more efficiently.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Dave_154
    Dave_154 Member Posts: 25
    I hate to say this but you do have the old pressuretrol and 0-30 gauge still installed, right? I'm pretty sure the 0-30 is code requirement, even with the 0-15 gauge installed.
  • Fred
    Fred Member Posts: 8,542
    He doesnt need the old Pressuretrol on the boiler even though most of us keep them on as a backup safety device, wired in series but the 1 - 30PSI gauge is required by code. (useless as they are)
  • waterjet
    waterjet Member Posts: 53
    edited December 2014
    The old gauge hadn't worked in years and the service technicians that were here never said a thing about it. I guess code is code, even if that furnace is rated at 15psi and the pressure relief valve is 15 psi.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • tim smith
    tim smith Member Posts: 2,807
    Great thread by you all, I find all of you to be very generous in giving all the time you do to this site, especially Dan. Thanks all for being so giving. Tim
  • waterjet
    waterjet Member Posts: 53
    Definitely! Everyone on here has been very helpful and my system is working better than it has worked in years.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • waterjet
    waterjet Member Posts: 53
    I made a minor adjustment to my steam system that seems to have done the trick. It was still building up pressure during cycles, so today I moved both Gorton #2's onto the long main and put the two Hoffman 75's on the long return. I turned the temperature up one degree, with the cpi set to 1 and it ran for almost 20 minutes without building up any pressure to shut it off, and the long return actually became slightly warm.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    that probably shows the water pooling is in the return, and should be easy to fix. check it with a level.--NBC
  • waterjet
    waterjet Member Posts: 53
    edited February 2015
    I don't see it as a problem, because the short return is always warm after the furnace runs.

    I am able to keep the temperature set at 68 day and night, and the house feels comfortable throughout.

    The venting was the most important thing that I did to improve this system, which is helping to keep the pressure low and heating the entire house more efficiently. I am considering swapping out one of the Hoffman 75's on the return line and replacing it with a Gorton #2. I think I'll try a test first to see if this might help keep the pressure down even more on longer runs.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • waterjet
    waterjet Member Posts: 53
    edited February 2015
    The strangest thing happened when I was doing a simple test to see if I might want to put a larger air vent on my long return line. I removed one of the Hoffman 75's on the return line and waited to see what would happen when I increased the temperature by two degrees. The funny thing is, that nothing really happened while the furnace ran for a little over 26 minutes, but when it shut off it sounded like there was a vacuum noise coming from the opening. I put the Hoffman 75 back in place and didn't think very much about it, until I went to bed. In all the time that we have lived in our house our bedroom has always been at least two degrees or more lower than the temperature set on the thermostat, but after my test, now the temperature is the same. It's like I bled the system and now it works more efficiently. Does anyone know what could have happened to cause this and if I still might want to increase the venting on this line or just keep it as is?
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • waterjet
    waterjet Member Posts: 53
    Update: I think that I do need a larger vent, because the temperature in our bedroom is back to two degrees below the thermostat setting.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    It is very possible the Hoffman has failed closed. Did you shake it when you had it off? Did it rattle? I'm sure you need more than 1 Hoffman 75 on a return line but if it's failed closed, it's like no vent. Besides that, Make sure the tapping that ythe Hoffman is mounted in/on isn't clogged as well. With the vent off, you should have seen some steam coming out of that tapping.
  • waterjet
    waterjet Member Posts: 53
    There are two Hoffman 75's on this return line and both are were new about three months ago. I did move one of them from the short main, because it didn't not seem to close properly on this line and hissed, until I tapped it. They are the cheaper, painted version, so I was told, but I will check them. I did order another Gorton today to ensure that this line is venting well and heat is getting to my furthest radiators properly.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    The green Hoffman 75'S aren't cheaper versions. They are identical to the unpainted 75's Hoffman sells today. Hoffman cut out the painting to save a few cents per unit on production.
  • waterjet
    waterjet Member Posts: 53
    edited February 2015
    Thank you Fred. Someone had told me they were of lesser quality and they actually do seem to be lighter and rattle more if you shake them.

    Just to be sure. Are the same type of air vents used on condensate return lines that are used on mains? This is the type of return that I was discussing previously.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    Yes same vent. You really don't need vents on the return lines. You want them on the ends of the Mains. The only reason to put them on the return is because you have no convenient place to install them on the end of the Main. When you do have to put them on the Return, you need to add additional venting to get the air out of the Main as well as the return.
  • Jamie Hall
    Jamie Hall Member Posts: 24,531
    Well now, Fred -- what you say is true, sort of. A two pipe systems will need vents on the dry returns, to handle the air which is vented through the radiator outlets (which are usually, but not always, traps). Further, systems using cross over traps instead of main venting -- as many vapour systems do -- have to have vents on the dry returns -- usually at the boiler -- and may not work properly at all if there is venting anywhere else in the system.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • waterjet
    waterjet Member Posts: 53
    I just wanted to be sure that the condensate returns didn't require a Hoffman 75H or similar vacuum type of valve, instead of the regular 75 air valve. Since it worked so well when I removed one of them, I'm assuming that adding a larger vent may help to achieve the same result; with more heating going to the furthest points in the system before the furnace shuts off.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • Fred
    Fred Member Posts: 8,542
    waterjet said:

    I just wanted to be sure that the condensate returns didn't require a Hoffman 75H or similar vacuum type of valve, instead of the regular 75 air valve. Since it worked so well when I removed one of them, I'm assuming that adding a larger vent may help to achieve the same result; with more heating going to the furthest points in the system before the furnace shuts off.

    Actually the 75H is not a vacuum vent. It is basically a non-vacuum vent with a higher Drop Away pressure (10PSI) compared to the 75 which has a 3PSI Drop away. You want the 75. The Hoffman Vacuum vent is the #76.
  • waterjet
    waterjet Member Posts: 53
    edited February 2015
    Thank you for clarifying that Fred. I got the two valves mixed up, because when I began upgrading this steam system it had one Hoffman 75H on the long main and the rest were 76A's.

    Also, thank you ensuring me that I'm using the correct type of air vent. For my house to feel this comfortable, with the cold weather that we are having now, is a major improvement and I've already noticed the savings in fuel.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.
  • waterjet
    waterjet Member Posts: 53
    Before I installed the new Gorton #2, I blew through it to compare it to the Hoffman 75 and was surprised when it seemed easier to blow through the Hoffman 75. I installed it and think there has been a slight improvement in the upstairs temperature in our bedroom, that is on this longer return.
    1984 HB Smith BB14-4 oil furnace with Carlin 100CRD burner heating an old two-pipe, gravity, steam system original designed for a coal furnace. Increased venting capacity with Gorton #2s and Hoffman 75s, and installed a Honeywell L408J1009 Vaporstat Controller to reduce pressure. Also replaced all dura-stat modules on traps; two with Barnes & Jones Cage Units in coldest rooms.

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