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Hydraulic separator design

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Ahcene
Ahcene Member Posts: 1
Hello,

I have an installation for heating an arena with a a heat pump and a boiler.

the hydraulic separator is used with the heat pump on the primary loop and the gas heater on the secondary loop, as shown in the attached picture.




Is it correct to install it like that??

Thanks

Ahcene

Comments

  • hot_rod
    hot_rod Member Posts: 22,472
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    Check to see if the heat pump requires a buffer tank, the manual usually shows how many gallons per ton of HP capacity.

    The new inverter drive can use smaller tanks, some can run without buffers, I've heard?

    What type of boiler? If it is a standard cast iron, it will need return protection on those low temperature zones.

    The boiler could be on the same side of the sep as the HP, so it uses the air, dirt,and mag function best.

    Here are a couple examples with a buffer. This shows 3 pipe buffer, which provides the lowest return for highest efficiency, for both HP and mod con..
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • leonz
    leonz Member Posts: 1,180
    edited March 2023
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    You should be using a battery of large Internal Air Separators, large Airtrol Valves and large Steel Compression Tanks in mounted in parallel with a common central pipe Tee'd into each steel compression tanks Airtrol Valve to remove air bubbles to do this as there are no bladder tanks to eventually fail, zero moving parts, no automatic air vents that will go bad and leak and air separators that have to be cleaned.

    By making plumbing the system in a single loop everything will be piped in series and you will be able to
    remove the air bubbles quickly.

    You are making the entire system harder to maintain which is something you do not want ever.
  • hot_rod
    hot_rod Member Posts: 22,472
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    All hydronic systems benefit from a good micro bubble air purger. A good brand and #30 expansion tank run about $180 online

    A 15 gallon Wessel compression tank and AirTrol fittings, sight glass come in around $ 995 at the same website.

    So for the difference you could buy 12 extra #30 tanks, about a 180 year supply. And have a more efficient system. I doubt many of the new cast boilers even have a top port for an AirTrol fitting? Certainly not the air elimination chamber in the sections.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • leonz
    leonz Member Posts: 1,180
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    I guess we are going to disagree Bob,

    Not knowing the size of the heat loads and the water volume is a sticking point.

    Keeping it even simpler by using a single large Wessels saddle tank, Internal Air Separator, gauge sight glass, airtrol valve for a single loop that could use manual flow regulator valves would probably cost less than the large microbubble air separator in the drawing.

    A large heating system like this needs simplicity to provide reliable heating and snow melting.

    My thoughts on this anyway.

  • hot_rod
    hot_rod Member Posts: 22,472
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    leonz said:

    I guess we are going to disagree Bob,

    Not knowing the size of the heat loads and the water volume is a sticking point.

    Keeping it even simpler by using a single large Wessels saddle tank, Internal Air Separator, gauge sight glass, airtrol valve for a single loop that could use manual flow regulator valves would probably cost less than the large microbubble air separator in the drawing.

    A large heating system like this needs simplicity to provide reliable heating and snow melting.

    My thoughts on this anyway.

    What is large? Rare to see even large radiant jobs hold more than 40- 50 gallons total fluid. So a 5 gallon diaphragm tank or 15 gallon compression.

    I suppose when you start talking thousands of gallons?

    An example in the Amtrol Engineering Book shows a system with 2,640 gallons

    1520 gallon compression tank
    OR
    364 gallon hydro tank

    The compression tank at 4150 lbs empty, when waterlogged weighs over 7 ton!
    The bladder tank 1737 lbs waterlogged.

    Price out a 1500 gallon ASME compression tank!

    What is an internal air separator?

    The separator in the schematic does hydraulic separation, microbubble separation, dirt down to 5 micron, magnetite down to .05 micron size.
    What compression tank provides those functions?

    A microbubble sep is a vessel with a media inside, fairly simple
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • leonz
    leonz Member Posts: 1,180
    edited March 2023
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    Bob, I did not offer my comment to argue with you or anyone else.

    A large system with a circulator could have cast iron or steel radiators with 1 1/4" pipe. As long as water is flowing out a boiler it will bring the air bubbles with it eventually and they can be stripped out of the water flow with a properly mounted horizontal Internal Air Separator using a riser to a steel compression tank.

    An air scoop of any size with a3/4 top tapping could be used to feed air bubbles to the airtrol valve for it to strip the air bubbles from the water flow too.

    A B+G Internal Air Separator is a cast iron NPT threaded tube with pipe wrench flats on both ends and a internal cast baffle plate that has 4 tappings; two (1 1/4") tappings and two 3/4" tappings.

    The (1 1/4") tapping for one size I.A.S. is for full water flow that passes over the baffle plate that forces the water and bubbles over the baffle and upward toward the riser pipe that reaches the airtrol valve that is threaded into the steel compression tanks bottom NPT tapping.

    I cannot upload a picture of a B+G Internal air separator from a Zoro image but they are simple enough as they do not use media to separate air bubbles just the water flow and the cast in place baffle.

    If you type in Internal Air Separator in the search engines search box an image of a red B+G Internal Air Separator should pop right up.

    All I do with my system is turn the thermostat up to drive any trapped bubbles out of the system at the beginning of the heating season.


  • dko
    dko Member Posts: 643
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  • leonz
    leonz Member Posts: 1,180
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    Thank you dko.
  • hot_rod
    hot_rod Member Posts: 22,472
    edited March 2023
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    A friendly discussion is what I had in mind😉
    Argue if you must.

    we have tested most all of the various types of air removal devices so we have data on what they are and are not capable of.

    Ask B&G if the sell more cast scoops compared to the various different high efficiency air devices they offer.

    Spirotherm developed the micro bubbler specifically because ramp type scoops were not doing an adequate job. Cast boilers were more tolerant to some air trapped up high. The mod con boilers don’t tolerate air well, any size bubbles.
    Assuming they are even installed properly and flowing within their comfort range, below 5 fps.

    If you had a micro bubble air purger on your system you would not have trapped bubbles to burp out every heating season👍🏻

    micro bubble  air purgers can be piped up to compression tanks, also
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • leonz
    leonz Member Posts: 1,180
    edited March 2023
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    Keeping things simple by eliminating air vent was one of many reasons I went with a steel compression tank as I had nothing but trouble with my old system when my water well collapsed and air slugs parked up in the high point of my system and I had to climb a step ladder to open the key vent to purge it.

    I have no more headaches in dealing with automatic air vents for the last 7 years with my coal stoker boiler.

    I thank the dead men and Mr. Holohan for making my system simpler. If I knew then back in 1982 what I know now I would still have my open to air saddle tank hanging in the ceiling making the plumbing even simpler.
  • hot_rod
    hot_rod Member Posts: 22,472
    edited March 2023
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    Air vents, coin operated, key operated, float type are for high point air elimination. With a good microbubble type purger at the boiler, you should not need all those vents, maybe just for first start up.
    Float type point air vents can actually suck in air if the system goes sub-atmospheric. Like when you pump at a compression or expansion tank.

    If you have any flow at all, even noisy flow, it will be removed at the purger near the boiler. It may take an hour or more depending on piping, zones, up and down, etc.

    I cant post pics right now without getting kicked off??
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • delta T
    delta T Member Posts: 884
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    Just checkin, but there will be a pump on the snowmelt loop.....right?
    Tinman