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  1. #1
    Join Date
    Feb 2008
    Location
    Saginaw Mi
    Posts
    5

    Johnson Flow switch issues

    Working on a P/J F61KB-11 flow switch with no isolation valves. Switch is bad and I want to just change the head. It looks like I can do this without loosing any water but cant recieve confirmation from Johnson. Anyone know for sure?

  2. #2
    Join Date
    Mar 2009
    Location
    Several Miles from Sane
    Posts
    1,458
    Sorry but I don't know for sure !

    Hey, you have a 50/50 chance it will work. If it doesn't you still have to drain the system down and replace the entire switch assembly anyway.

    I say go for it, it just might work.

    As far as JCI, they will not tell you it can be done cause they sell parts not advice. JMO

    Let us know how it turns out.
    If sense were so common everyone would have it !

    All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!

  3. #3
    Join Date
    Jan 2008
    Location
    Taxachuesetts
    Posts
    198
    I would bet the paddle is long gone. Any chance you can find a place for a DP switch, and just abandon the paddle POS?

  4. #4
    Join Date
    Feb 2008
    Location
    Saginaw Mi
    Posts
    5
    both good points, didn't want to pipe in a differential switch just for cost reasons. But it will probably be cheaper than spending all day bleeding a 30 year old National guard armory. That is also why I think the paddles are fine, plus I can watch the linkage fully swing with flow, the switch is just shot. Thinking about doing it on the fly and hope a vacuum holds out. Trying it in about an hour, thanks for the responses! Also, I did recieve a call from JCI and they recommended not doing changing heads due to calibration issues. I thouhgt that was what the calibration screw was for.

  5. #5
    Join Date
    Jan 2003
    Location
    USA
    Posts
    1,685
    I wouldn't even consider replacing half of it. What’s going to happen when it sticks closed a week after you get done with this franken switch?

    Turn off the pumps, boiler / chiller, make-up water, relieve the fill pressure if possible. Prep the new one and do it on the fly, and of course your going to get wet....



    I got a good story from a “hot” swap of a sensor well. We had a pretty large (~5-10k gal) domestic hot water tank with a steam HX that heated the water. For whatever reason the sensor location was shown on the discharge of the tank, and that’s where it got installed. This sensor controlled the steam valve that heated the water. This worked fine with continuous flow out of the tank. During the night when there was no demand, the discharge line would be stagnant and cool off. This caused the steam valve to open, and the water in the tank got hotter than hell. Realizing that a well would have to installed in the actual tank, we found a tap that could do the trick. Being young and stupid at the time, I figured a hot swap was not a problem. Manually closed the steam valve off and at the end of the day I specifically remember checking what our sensor was reading to get an idea of how hot the water was. ~100F (on the discharge)…..no problem. With the new well taped and doped up, I unscrewing the plug telling myself it was a cake walk.

    Well as the last thread of the plug let lose and it shot across the room (note to self, large tank will still have plenty of pressure even with makeup cut off), I got a real good idea of how far off the discharge sensor was. Trying to hold back that lava hot $hit, I realized I had made a major error. I wanted to rip my off my shirt, and scream like a girl. If I had to guess that water was well over 160F, it filled the room with fog. Being a trooper I got the new well in, but not before getting scalding burns over most of one arm and all of my chest, and down my legs. It took a few days before the wonderful burning sensation went away.

    I have done a good handful of hot swaps since, but never again with "hot" water….

    Moral of the story, be careful gents….a poached weenie is no fun.
    Last edited by orion242; 10-28-2009 at 11:04 PM.

  6. #6
    Join Date
    Nov 2005
    Location
    Captive DDC Customer
    Posts
    108
    agreed about the weenie, hands & face. Have the water cooled and sucking backwards on the port (cooled, as it may decide suddenly to push water out the port instead of suck air into the port) or completely drained before unscrewing a flow switch from a pipe.

  7. #7
    Join Date
    Sep 2007
    Posts
    132
    I used to hot swap wells and such in large tanks, but would always isolate the tank from the system and open a drain valve, which would put the tank into a very slight vacuum. Then I'd pull the old well, and slap the new one in while the tank was "gulping air". Never once got wet, or had to drain a tank.
    There's a lot to know.

  8. #8
    Join Date
    Feb 2008
    Location
    Saginaw Mi
    Posts
    5
    I did it on the fly, took about a gallon to the face. all worked out though.

  9. #9
    Join Date
    Mar 2009
    Location
    Several Miles from Sane
    Posts
    1,458
    New switch, full warranty, a little wet and you become the hero.

    Sounds like hopkins34 comes out the winner !
    If sense were so common everyone would have it !

    All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!

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