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Hurst steam boilers+pneumatics

I have one question: It's normal for a commercial steam boiler to have a pneumatic relay on the side to fire the burner (When a pneumatic control system is used) But every time the unit fires, there is a deafening release of air from the relay. We think the backlash involved is destroying the delicate the electrical contacts inside. This has happened at least 10 times this season so far, and is getting costly. (The relay has been replaced once, and it's insides replaced at least 5 times) It's an odd problem, any ideas?

Thanks in advance, the other pneumatic control air threads were of no help.


  • Maker's name?

    What make and model would this be?--NBC
  • Dave in QCA
    Dave in QCA Member Posts: 1,777
    Pneumatic Pressure?

    I see that you have a new compressor for the pneumatic system.  The air line should go to a pressure reducing and filture and dryer equipment.  It looks like I can see that equipment on the wall in the background, in fact it looks like there might even be 3 pressure reducing stations. 

    So, the big question, what is the air pressure once it is in the pneumatic system.  It should be 20 psi. --  No more, no less.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • RJ_4
    RJ_4 Member Posts: 484

    Most all old pneumatic systems failed to heat, when air press. was lost bldg would go to full heat. It is probably normal for the boiler relay to bleed off on a call for heat,  The 3 way valves on the wall are probably for day night changover.  day 15 psig,  night 18-25 psig.  or summer winter changeover,  summer 15 psig, winter 18-25 psig. check bldg thermostats to you which system you have. Are the tanks on the wall connected to the pneumatics ?  Some of the old systems had air compressors with little air storage so external tanks were used.
  • Smith19
    Smith19 Member Posts: 95

    As you can see from the image, the Burners are Gordon Piatt model R's from 1995. I think they have special GOPEG relays on them. As for the actual pneumatic set up, It has a few pressure reducing valves. These blow off periodically as they should. As for the four actuators you see lined up, those are a redundant 1952 set up to control air. They were cut off after the new compressor was put in and weep badly, so I'm guessing the PSI falls below 20. Are GOPEG relays poorly designed? Of course we can't really know as I think that's a part that is no longer in stock due to GOPEG's closure.

  • Smith19
    Smith19 Member Posts: 95
    Pneumatics cont.

    NBC, the compressor is quincy and like I said the burners are GOPEG R's and the boilers are Hurst LPW's.

    There is also a refrigerant dryer in between the compressor pumps as you can see, but our climate here is too dry for it to blow off periodically.
  • RJ_4
    RJ_4 Member Posts: 484

    just as the phrase dead men of steam we can use dead men of pneumatics, the men who are good on old pneumatics are slowly disappearing  I would look at it for you, I live in colorado. i am a retired Steamfitter.
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