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Doing a blowdown under pressure.

ChrisJ
ChrisJ Member Posts: 15,592
Before firing the system up again for the fall I really want to do a blowdown.  The last time I did this I closed both of my king valves and the return valve and then adjusted my pressuretrol for 3psi or so.



This time I want to go to a higher pressure, but not sure how high is recommended?  I'm assuming 10PSI or under should be perfectly safe?



Also,  I don't want to mess with my pressuretrol setting if possible.  Is it safe to just hold the mercury bulb from tripping with my finger and let go when I hit the desired pressure?   My concern is I don't know if this may damage the diaphragm in the pressuretrol.
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

Comments

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    How high were you planning to go?

    Check your manual, but I think the max operating pressure is around 20 psi, and the surge pressure is around 50. I think your safety valve will pop before you can damage the pressuretrol. You wouldn't want that to happen.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • ChrisJ
    ChrisJ Member Posts: 15,592
    safety valve

    I believe the T&P will pop at 15PSI so I don't want to get close to that but I'm wondering how high most guys go?  5? 8? 10? 12?



    I guess one of my concerns is I noticed last time I did this at 3PSI the pressure crept up a little bit past where I shut the burner off so my fear is if I get too close to 15PSI I might be very sorry, or maybe its good to test it?  Something tells me its a bad bad thing when that pops.
    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
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Very bad

    unless you're into scalding. Dan has a description of what it's like on here somewhere. It didn't sound fun.



    Anyway, I'm curious about how much pressure to use too. Part of my new header design was to allow for blowing down the boiler. There is a short video on the subject somewhere in the resources. I'll see if I can find it when I get home tonight.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • JStar
    JStar Member Posts: 2,752
    Pressuretrol

    You can jump out the electrical contacts on the Pressutrol to make it easier.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    That's what I was thinking.

    When I skimmed it last year I just jumped the terminals in the lwco for the pressuretrol and the thermostat with a pair of clip leads.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • ChrisJ
    ChrisJ Member Posts: 15,592
    shorting / jumping pressuretrol

    I thought about that too, except its just as easy to simply and a lot safer hold my finger on the mercury bulb.
    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
  • gerry gill
    gerry gill Member Posts: 3,078
    why dont you just

    open a return plug on the side of the boiler and go in with a homemade 'wand' hooked to a garden hose and wash out the boiler. I did it for a customer today. You'll be amazed at what comes out.
    gwgillplumbingandheating.com
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • ChrisJ
    ChrisJ Member Posts: 15,592
    hosing it down

    Should I make up a custom head for my pressure washer using soft copper tubing? :)



    I'm assuming the easiest way to hose a boiler down like my EG-45 would be through the skimmer?
    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
  • Rod
    Rod Posts: 2,067
    Flushing the Boiler

    Hi Chris-

      I don't know about using a pressure washer. That might be overkill! :)  It works quite well just using a garden hose. I believe your safety is on top of the boiler and that might be the best place to flush from. Also you can use your skim port.

    I hook one hose to the bottom boiler drain valve and lead it to a floor drain and then just run a lot of water through the boiler using another garden hose and a wand I made up with fittings from Home Depot.  The water splashing around the inside cleans off most of the sediment.

    - Rod
  • gerry gill
    gerry gill Member Posts: 3,078
    i have a copper pipe

    with a ball valve that has a female hose connection on it and the working end is a 90 degree elbow with the leg cut off so that the water still goes sideways but is essentially a straight pipe. I just roll it in circles inside the boiler.
    gwgillplumbingandheating.com
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    edited September 2012
    Video

    Here's the video on near-boiler piping that mentions blowing the boiler down under pressure. He says 10 lbs. That'd make me a little nervous.



    http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
This discussion has been closed.