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Does this sound right?

DanC Member Posts: 1
First off, this is a great site and I've been reviewing it for a long time and cleared up a lot of small issues with my 5 year old WM EG45 steam boiler!

I realize the 30 psi gauge and pressuretrol is required as is, but I think they're next to useless for low pressure situations in steam settings.

Like I say, I've been doing tons of reading here (just retired) and want to add a low pressure 0-3 psi from Wika (33041) and a vaporstat 0-16 oz (L408J1009).

I'm going to add these and tee them into the present configuration after the steam trap. The vaporstat will control the day-to-day steaming and I'll set the pressuretrol cut-out at 5 lbs or more to act as an extra safeguard. 

>>>does the required series wiring mean I can simply continue the 2 wires from the pressuretrol and terminate them on the R and B screws of the new vaporstat? Or am I wrong on that?

I know it's Thanksgiving so I won't do anything till next week after waiting for help from you guys. This place is great and thanks for any and all responses! 


  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    Series v parallel

    What you're describing sounds like a parallel circuit, though could be misinterpreting what you're saying.

    In a series circuit, you'd take the hot wire and connect it to the first switch in the series, then take a wire of the same color from the other terminal to the next switch, and so on, until you reach the last switch, where you'd connect the neutral wire to the second terminal, completing the circuit. This means that, if any switch in the series is open, the circuit will be open.

    In a parallel circuit, you would connect a hot wire and a neutral wire to each switch so that each switch is capable of completing the circuit, and the circuit will only be open if all the switches are open simultaneously.

    If you're like me, a picture would be clearer than a description. I don't happen to have one, but there's an article on Wikipedia that has pictures. See http://en.wikipedia.org/wiki/Series_and_parallel_circuits.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2011

    I had to draw it on a picture to explain it.  Starting at the top of the photo, you will run one wire from the pressuretrol to the vaporstat.  Then you take your original two wires (the two that are on your pressuretrol now) and send one each to the vaporstat and the pressuretrol.  Your new vaporstat will come with a diagram that will tell you which terminals to use.  For most applications the center terminal is not used.
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,188
    edited November 2011

    Do it yourself electrical work isn't for everyone, and obviously you can render an important safety device useless if you do the wrong thing.  Test your work when done by manually tripping the devices to assure that they afford protection.

     The photo above shows the proper wiring, while the improper piping shown can quickly destroy both controls, affording no pressure control to the boiler.   Notice there are no steam pigtails (boiler traps)?   Honeywell requires them ahead of the elbows to protect the controls and piping from scale and corrosion.   

    That said, each control should have its own pigtail, as they clog very often (we've seen some clog every two years) and controls sharing a pigtail will both be rendered useless if the thing clogs.

    New York City requires a redundant pressure safety on steam boilers in all multiple unit buildings.  The higher one must have a manual reset, so the operator is alerted to the failure. 

    The same arrangement will maximize safety in a private residence. 

    A vaporstat's benefit to the system is only realized when that system builds steam pressure, meaning when every radiator is filled completely with steam and all the vents are closed.  On a properly sized and vented system this rarely happens.

    In that properly designed system, only on the coldest (design temperature) days of the year will the system be completely filled with steam and only then will the vaporstat act and save you fuel. 

    Let me pass along that those old steel pigtails can be beasts to get loose out of the boiler if they have been there for years.  But they're easy to snap off right at the tapping.   Mess with it, break it off and you'll cry a hundred tears.  A thousand tears on a cold day.

    Good luck with your project and enjoy a healthy and long retirement. 
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