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Saddle valve use for air purge??

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by ozzie88, Nov 25, 2012.

  1. ozzie88

    ozzie88 Member

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    This systom i am helping a friend on has NO air release purge valves anywhere.Still can here air gurgle in the pipes but is better now since i tried valve. Couple on the top baseboards is all. I thought in stead of taking everything apart to put a air valve in why not use a saddle valve,?? Put on,poke hole, let air out and cap off. I did put one on it seems to work good.good to 1 1/4 pipe.
    Anything I am missing here?[​IMG]

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  2. Bob Rohr

    Bob Rohr Minister of Fire

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    where do you plan on installing it? It may work as a high point vent, but not as an inline air eliminator. Check the temperature rating.
  3. peakbagger

    peakbagger Minister of Fire

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    It might help a bit but its no substitute for a full size purge valve. My parents had some small bleed valves installed on their loops and the service techs were real careful never to drain the lines as it was a major PITA to get the air out. I drained a loop once and it would not purge and I needed the heat as the place was cooling down. I installed a full size purge valve on the return and it took about 5 minutes to purge.

    I really dont like saddle valves, too easy to hit accidentally and spring a slow leak.
    Taylor Sutherland likes this.
  4. ozzie88

    ozzie88 Member

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    I putting it at high point just before it goes into the side tank on left side ,pipe goes into tank 30inchs so air get traped there, I know it cheap way to try fix this but wow,you should see what he has running on ONE taco-pump. His house has 3 zones all with these hand valves on them and then there his moms house next door 45foot run of 1 1/4inch pipe to 2 old steam radiators with air bleeders on them, he uses these hand valves to control flow rate,said he doesent believe in zone valves or control valves etc? and he wonder why not getting all air out? Get the picture??

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  5. Bob Rohr

    Bob Rohr Minister of Fire

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    The system really needs an air elimination device. Looks like you have enough isolation valves to cut an air scoop into the supply line off the top of the boiler. A microbubble type would be best, but the inexpensive cast iron scoop or ramp type would be a big improvement.

    That boiler is an ideal location to remove small air. Remove the large expansion tank install a float type air vent at that tapping. Then connect both expansion tanks, and the fill valve to a tee where the small expansion tank is now attached, if it is connected to the return pipe? Hard to tell in that picture? This will solve a few issues, air removal and you will be pumping away from the expansion tanks do the pressure the circ adds to the system will aid in proper air removal.

    I doubt a saddle valve will help much and the rubber seal where it saddles on will probably not last long in that environment.

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  6. ozzie88

    ozzie88 Member

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    Thanks for the info, the drawing looks good and will work, I do understand what you said and why it makes sences. I even have an cast iron air scoop now I will show him this and see if i can talk him into doing this,it wont be much work at all. See he wants it to circulate without pump on,since I added that side tank he says it dosent now? But i told him it has so much air in it it cant move water with air bubbles,heck it gurgals when pump on you can here all air in it. [cavitation] I have 4 tanks and my water will move threw them all with no pump,I have all air out. I know i have to get air out for it to work right,this is such a low buget operation just thought of saddle valve,
  7. Bob Rohr

    Bob Rohr Minister of Fire

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    Tough call, but if it is worth doing, it's worth doing right:) You need to move fluid at least 2 feet per second to push air along, and get it back to a point where a vent can function. The old gravity systems were an engineered system, much different than todays small piped systems. Small diameter piping needs flow velocity, imparted by the circ pump, to overcome the piping resistance.

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