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Let's Get The Water Back In The Boiler!

New England SteamWorks
New England SteamWorks Member Posts: 1,505
edited April 2023 in Strictly Steam

We are working with a church that has (naturally) motorized zone valves. They are utterly unable to control the water level. If they leave the VXT on (with 10 minute delay), the boiler floods. If they turn it off, the boiler goes off on low water when no one is around.

Dan has an excellent video about this scenario here:


https://youtu.be/uDOuq-dBEHE

The relevant parts are 1:10 and 2:40.

We informed them that the only solution we could think of was to add a boiler feed tank. The cost of which did not exactly leave them feeling thrilled.

Then today my guys ran into this:


Zone valves, no tank. Copper lines from the header to after each zone valve. No issues with water level. Me thinks the two issues are connected, and I am wondering if anyone has experience with this? Certainly easier than a boiler feed tank if my hunch is correct…

Those copper lines pressurize the returns, and Get The Water Back Into The Boiler! Right?

New England SteamWorks
Service, Installation, & Restoration of Steam Heating Systems
newenglandsteamworks.com

Comments

  • Steamhead
    Steamhead Member Posts: 16,796

    ISTR that shows up in Lost Art someplace, but I don't have mine handy- @DanHolohan ?

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,513

    I don't have the book with me.

    Retired and loving it.
    mattmia2
  • Jamie Hall
    Jamie Hall Member Posts: 23,168

    Not so sure they pressurize the return lines — but they do equalize pressure between them and the headeer (which is where they look like they are going — not to a return). When the zone valves close, if they weren't there you could have much lower pressure in the returns downstream holding the water up against the boiler pressure.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 9,575

    Isn't thre another way to make this work with a lot of drips and a few vacuum breakers or something simialr?

  • Jamie Hall
    Jamie Hall Member Posts: 23,168

    If you are running a system with crossover traps and dry returns, then when the zone valve closes the crossover trap for that main will open very quickly and the main and dry return will equalize at dry return pressure. That works for pressure, but you do need drips — ideally one on each side of the zone valve. This all works provided the steam pressure is low enough that the water can't back out of the cold return into either the main or the return through the drip.

    I can easily see how, if the boier pressure is higher, however, the water could be raised as high as the main if the main and boiler weren't equalized. I'd need to see the rest of the piping and know the boiler pressure, though, to see if my guess was any better than speculation..

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505

    It's a 1-Piper, no traps.

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JohnNY
    JohnNY Member Posts: 3,226

    Is it ok to like this? Whoever thought of it understood what needed to happen and took a non-conventional approach to get there. I wouldn't have done it, but I don't hate it.

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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    mattmia2Alan (California Radiant) Forbes
  • JUGHNE
    JUGHNE Member Posts: 11,042

    I had zone valves on a 2 pipe system in a school that was to be demoed in a few years.

    I adjusted the gates to not fully close thinking that this would keep the supply pipe from going into a vacuum and not returning water. It seemed to work OK for a hack job.

  • 109A_5
    109A_5 Member Posts: 1,377

    Awhile ago we ran into a church (naturally) with motorized zone valves.

    How was this job resolved ?

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,831

    "What ever works in a fight" Marquis of Queensbury rules only get you so far sometimes 😉...The longer I do this, the more unconventional solutions join the conventional ones in the 🧰 toolbox. Mad Dog

  • ScottSecor
    ScottSecor Member Posts: 851

    I'm mad at myself for not trying something similar. We currently have five or six churches with the same problems and not longer service a few more with similar problems. Today with Megapress and the Megapress "threadolet" tap tool it would not be all that hard to add a few much needed bypass tappings.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453

    I think the copper tubing is there to drain the water in front of the zone valve so they don't hammer when they open.

    Mad Dog_2
  • realliveplumber
    realliveplumber Member Posts: 354

    Then why wouldnt they have tapped it off of the bottom of the pipe, instead of the side?

    New England SteamWorksCLamb
  • 109A_5
    109A_5 Member Posts: 1,377

    I'd would have made it NOT look like a sloppy add on, or after thought. I wonder if the tube just went from one side of the valve to the other would have worked just as well, using a lot less tubing and not as sloppy. They probably just went with the easiest places to drill the holes.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    New England SteamWorkscbprov
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505

    Remains unresolved…

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • ChrisJ
    ChrisJ Member Posts: 15,588
    JohnNY said:

    Is it ok to like this? Whoever thought of it understood what needed to happen and took a non-conventional approach to get there. I wouldn't have done it, but I don't hate it.

    I think it's ok to like anything that works reliably.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    Mad Dog_2
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505
    edited March 2023
    Hey! We found another one!


    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,831
    If they tapped the bottom of the pipe, it would become a Trap...Mad Dog
    New England SteamWorks
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    edited March 2023
    I am going to have to dig through my files. I had a one pipe system I wanted to zone and worked out a way to get it to work properly. I think I ran it past Denny Molloy and it passed. IIRC you have to run an equalizer down from the supply on the system side of the zone valve to the wet return from that zone and then run the return over to its own trap before going into the condensate pump or boiler feed tank. The zone then runs its own pressure and the boiler can do whatever pressure it wants. Basically you pipe each zone as though it has its own boiler and the zone valve and trap/condensate tank isolates the zone from the common boiler.
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  • 109A_5
    109A_5 Member Posts: 1,377
    I like this last one better, although I think the check valve serves no useful purpose. Since relieving the vacuum that is apparently trapping the condensate in the return system would flow in the same direction as the steam. I suppose you could put a vacuum break after the zone valve but that just lets more oxygen into the system.
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    @realliveplumber They tapped it off the side beacause it was easier and they didn't know what they were doing anyhow.


    The right way to do a zone valve (if you must have one) is if the pipe is pitching down to the valve inlet put a drip on the inlet pipe and drip it back into the boiler or into a wet return to keep the condensate off the valve when it is shut. Not into the boiler supply or header.

    If faced with the opposite....zone valve installed in a pipe pitching up the inlet side will be fine if the condensate can drain back counterflow. On the outlet side it will collect condensate when the valve is closed drip it through a check valve installed below the boiler water line or use a steam trap and drip either one to a wet return.
    Mad Dog_2
  • Steamhead
    Steamhead Member Posts: 16,796
    Steamhead said:

    ISTR that shows up in Lost Art someplace, but I don't have mine handy- @DanHolohan ?

    Well, I stand corrected- as far as I can tell, this isn't in Lost Art. But I know I've read it somewhere.........
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    Mad Dog_2
  • dko
    dko Member Posts: 576
    Steamhead said:

    Steamhead said:

    ISTR that shows up in Lost Art someplace, but I don't have mine handy- @DanHolohan ?

    Well, I stand corrected- as far as I can tell, this isn't in Lost Art. But I know I've read it somewhere.........
    https://heatinghelp.com/systems-help-center/zoning-steam-systems/
    The last sentence
    mattmia2New England SteamWorks
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,831
    Its all a  blur...Holohan wrote..thats close enough as a cited footnote!  Mad Dog
  • ScottSecor
    ScottSecor Member Posts: 851
    I may be wrong, but I'm almost certain I've seen large flanged (four, five or six inch) steam zone valves with that bypass built in. Possibly Minneapolis Honeywell?
  • jumper
    jumper Member Posts: 2,228
    ChrisJ said:

    JohnNY said:

    Is it ok to like this? Whoever thought of it understood what needed to happen and took a non-conventional approach to get there. I wouldn't have done it, but I don't hate it.

    I think it's ok to like anything that works reliably.
    I'd be proud to think of this although I am partial to feed tanks.
  • retiredguy
    retiredguy Member Posts: 898
    edited May 2023
    I have never seen a set-up like that with copper lines that bypass the zone valves. They may be doing this as a bypass to overcome holding condensate in the piping. I may put just enough steam in the piping to break the vacuum but not enough to add heat to that zone. On a 2 pipe system you need to make sure that you have the system vented properly with or without vacuum breakers on the return lines. On a 1 pipe system the vents on the radiators solve the problem. Normally, on a steam system that is zoned, each zone should have a drip trap installed before the valve to get rid of any condensate that may be present before the valve. On this job however, the zone valve may be close enough to the header and the boiler that the drip trap may not be needed although if I were installing the zone valves I would have done the job correctly and installed the drips. As to the necessity of a condensate pump system, every job is different. Some jobs need them and some do not. As @ScottSecor mentioned, I knew of 2 ways on large steam systems to install zone valve, they were either installed with a "step control" to open the valve very slowly in steps or a 2nd small bypass valve was installed that would open first to warm-up the zone before the large valve was opened. As I have said many times in my 40 years in the business, every day you can learn something new and today was no different.