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Expansion tank sizing

samstusamstu Member Posts: 1
edited August 12 in Gas Heating
Hey everyone. Replacing an old Weil-McLain with a Burnham Series 2 299k BTU (input).
There are 6 loops going to 6 apartments (Building size is approximately 5,800 Sq Ft).
-It is a baseboard heating system

The heating contractor has ordered an Amtrol Extrol SX-60V expansion tank (32 gallon tank volume) to use on the system (floor standing).
Reading the literature on Amtrol's website (link below), it appears that this model is grossly oversized.
However, when I pointed this out to him, he insisted that it's what my system needs.
So I turn to you: Is there any way that a 299k boiler would need such a large expansion tank?

Here is a link to the Amtrol sizing chart:
http://www.amtrol.com/media/documents/extrol/9015183_07_16_EXTROL_IO.pdf

Amtrol Extrol Specification details:
http://www.amtrol.com/media/SUBMITTAL/p44_Submittal_01_17.pdf

And if it is too big, will that cause any problems? Is it worth arguing over or should I just let it go?

Thank you!

Comments

  • hot rodhot rod Member Posts: 7,283
    Is it an old iron pipe system? The sizing has a bit to do with the total system volume.

    Certainly no issue with over-sizing, other than cost.

    Maybe he had one sitting around in his shop :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 2,840
    The only way to size a tank correctly is to know the water volume in the system . Two ways to do this:
    1. calculate the water volume in the boiler and the pipe fittings and baseboard.
    2. Drain the system and the fill and vent it using a water meter to read the water volume.
    3. 3 Guess

    As @hot rod said oversizing (in this case) will not be a problem other than cost
  • lchmblchmb Member Posts: 2,562
    and if you guess make it bigger...;)
  • MikemanMikeman Member Posts: 1
    My residential hot water boiler system would occasionally raise in pressure when all three zones called for heat and possibly the domestic hot water demand at the same time. At times the pressure relief valve would blow off some water.The boiler had a small, properly functioning Extrol EX30 expansion tank. I finally plumbed in a second EX30 tank next to the first, figuring two small tanks were better than one larger. If one fails there is still some protection from the other. I don't believe the expansion tank can be too big because the air pressure in the tank controls the point at which the bladder moves. I also assume that if there were an internal leak from the domestic water side the system pressure would eventually rise no matter how big an expansion tank one had. My question is whether there is any error in my thinking or possible problems I should watch for
  • leonzleonz Member Posts: 126
    samstu said:

    Hey everyone. Replacing an old Weil-McLain with a Burnham Series 2 299k BTU (input).
    There are 6 loops going to 6 apartments (Building size is approximately 5,800 Sq Ft).
    -It is a baseboard heating system

    The heating contractor has ordered an Amtrol Extrol SX-60V expansion tank (32 gallon tank volume) to use on the system (floor standing).
    Reading the literature on Amtrol's website (link below), it appears that this model is grossly oversized.
    However, when I pointed this out to him, he insisted that it's what my system needs.
    So I turn to you: Is there any way that a 299k boiler would need such a large expansion tank?

    Here is a link to the Amtrol sizing chart:
    http://www.amtrol.com/media/documents/extrol/9015183_07_16_EXTROL_IO.pdf

    Amtrol Extrol Specification details:
    http://www.amtrol.com/media/SUBMITTAL/p44_Submittal_01_17.pdf

    And if it is too big, will that cause any problems? Is it worth arguing over or should I just let it go?

    Thank you!

    ======================================================

    If it were me:

    I would cancel the order for the bladder expansion tank because you can have him install a steel expansion tank in the ceiling joists of the basement near the new boiler and not have to deal with having an air scoop, bleeding radiators and have a much simpler system to live with.

    The steel expansion tank has no bladder and depends on the steel expansion tanks having a 1/3 volume of air and 2/3's volume of water to do the same job with an airtrol valve to control the air volume in the system.

    All that is needed is to have a line coming from the pressure line above the boiler to the airtrol fitting where the hot water and micro air bubbles
    rise into the airtrol valve from one half of the casting and are absorbed by the cooler water inthe steel expansion tank and the cooler water sinks back into the system from the cool water return in the airtrol valve

    The Airtrol valve has no moving parts and just sits there hanging in the
    basement ceiling joints and does its job silently

    You can simply install multiple steel expansion tanks and airtrol valves in the ceiling joists and have excellent air trapping results if you do not have the room for a single tank.

    You do not need automatic air vents in your system either and I do not miss bleeding baseboard radiators.

    My system operates between 4 and 12 PSI with zero issues on oil and coal.
    Save your money and your sanity in the process as a steel expansion tank will last for 50 plus years.


    OH!!, if you already have a steel expansion tank in the basement ceiling joists you can still use it-do not let them rip it out-at most it needs an airtrol valve and then you will be in fat city and not have to bleed radiators if you have them install drain valves in the return lines in the basement to power purge the air from the systems cold water when filling it.
  • STEVEusaPASTEVEusaPA Member Posts: 1,639
    leonz said:


    If it were me:

    I would cancel the order for the bladder expansion tank because you can have him install a steel expansion tank in the ceiling joists of the basement near the new boiler and not have to deal with having an air scoop, bleeding radiators and have a much simpler system to live with...

    I'm afraid I don' concur. Who wants to hang, what is probably a monster size tank, with all that weight, from ceiling joists.
    Without seeing the entire system, piping, etc., that's a tough call to make from a computer. Sure simpler.
    But I'd rather go with the properly sized bladder tank, modern air elimination. Easy to isolate and check.
    steve
  • hot rodhot rod Member Posts: 7,283
    leonz said:

    samstu said:

    Hey everyone. Replacing an old Weil-McLain with a Burnham Series 2 299k BTU (input).
    There are 6 loops going to 6 apartments (Building size is approximately 5,800 Sq Ft).
    -It is a baseboard heating system

    The heating contractor has ordered an Amtrol Extrol SX-60V expansion tank (32 gallon tank volume) to use on the system (floor standing).
    Reading the literature on Amtrol's website (link below), it appears that this model is grossly oversized.
    However, when I pointed this out to him, he insisted that it's what my system needs.
    So I turn to you: Is there any way that a 299k boiler would need such a large expansion tank?

    Here is a link to the Amtrol sizing chart:
    http://www.amtrol.com/media/documents/extrol/9015183_07_16_EXTROL_IO.pdf

    Amtrol Extrol Specification details:
    http://www.amtrol.com/media/SUBMITTAL/p44_Submittal_01_17.pdf

    And if it is too big, will that cause any problems? Is it worth arguing over or should I just let it go?

    Thank you!

    ======================================================

    If it were me:

    I would cancel the order for the bladder expansion tank because you can have him install a steel expansion tank in the ceiling joists of the basement near the new boiler and not have to deal with having an air scoop, bleeding radiators and have a much simpler system to live with.

    The steel expansion tank has no bladder and depends on the steel expansion tanks having a 1/3 volume of air and 2/3's volume of water to do the same job with an airtrol valve to control the air volume in the system.

    All that is needed is to have a line coming from the pressure line above the boiler to the airtrol fitting where the hot water and micro air bubbles
    rise into the airtrol valve from one half of the casting and are absorbed by the cooler water inthe steel expansion tank and the cooler water sinks back into the system from the cool water return in the airtrol valve

    The Airtrol valve has no moving parts and just sits there hanging in the
    basement ceiling joints and does its job silently

    You can simply install multiple steel expansion tanks and airtrol valves in the ceiling joists and have excellent air trapping results if you do not have the room for a single tank.

    You do not need automatic air vents in your system either and I do not miss bleeding baseboard radiators.

    My system operates between 4 and 12 PSI with zero issues on oil and coal.
    Save your money and your sanity in the process as a steel expansion tank will last for 50 plus years.

    Leon, you are stuck in the horse and buggy days :)

    Sure if you have a working compression tank, run it till it drops, sometimes literally.

    The diaphragm tanks with micro bubble eliminators add so much value to modern hydronics.

    Heck, some of the new boilers only hold 1 gallon of water, why would You hang a large volume un-insulated tank above it?

    An Extrol 15 or 30 covers a lot of new boiler installations.




    OH!!, if you already have a steel expansion tank in the basement ceiling joists you can still use it-do not let them rip it out-at most it needs an airtrol valve and then you will be in fat city and not have to bleed radiators if you have them install drain valves in the return lines in the basement to power purge the air from the systems cold water when filling it.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • leonzleonz Member Posts: 126
    edited November 1
    I am not a licensed plumber, I am a homeowner and end user of a steel expansion tank system with my dual fuel coal stoker boiler. They work and always have worked which Dan has described very well in his well written books about plumbing and heating.

    What is so hard about hanging a steel expansion tank and holding it in place with pipe straps OR creating a hanging shelf to hold the tank in the ceiling joists of the basement?

    If there is already a steel expansion tank in the basement(most likely) why remove a perfectly good appliance that has no moving parts to fail?

    At most it may need an airtrol valve and the airtrol valve can be installed with the tank in place as long as one is careful in installing it.
    Perhaps all that is needed is to just lower it down and putting it in a pipe vice to install the airtrol valve. and then hanging it back up with pipe straps which is not that big a job with a second set of hands and a step ladder.

    The steel expansion tank does not need an air scoop UNLESS you wish to use an air scoop for large diameter piping coming off the boiler to feed the steel expansion tank.

    BUT in saying that you can use a B+G steel expansion tank of up to 100 gallons in capacity with a 3/4" inch tapping and no large diameter piping to feed it.

    Smaller expansion tanks can be tied together in parallel to create the needed amount of expansion capacity with a bit of planning and after the airtrol valves have been secured in the steel expansion tanks they can be lifted into place and then the ball valves and copper or steel piping connections can be installed and then tied into the hot water feed line coming from the boiler.

    if you use a 100 gallon tank you will have 67 gallons of water in it and 33 gallons of air for compression which will allow the end user to have a very low operating pressure like I have which runs from 4-12 pounds. I am using a B+G NRF25 3 speed circulator to feed hot water through
    225 feet of baseboard which I absolutely hate and I wish I had cast iron radiators to hold even more water.

    Bladder tanks are not all that great and I am glad mine is gone as the extra capacity allows me to have a lower operating pressure and much less water noise.

    Using bladder tanks also requires automatic air vents and they will fail and leak- I don't have that problem anymore and no longer have to blow $10.80 to replace one each time they start leaking.

    They still work and work very well so why reinvent the wheel if the system still has a steel expansion tank hanging in the ceiling?

    If I had known better in 1982 when they installed my wood and coal hand fed boiler I would have never let them rip out the horizontal open to air expansion tank that was hanging in the ceiling joists above the old boiler.


  • STEVEusaPASTEVEusaPA Member Posts: 1,639
    67 gallons of water is 558 lbs, plus tank hanging over your head. And it's not maintenance free. I wouldn't want the task of draining/recharging it if (when) it became water logged.
    steve
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 2,840
    I wouldn't install a steel compression tank now if I had another choice. Too many problems (waterlogging) and you can't use automatic air vents with them.

    that being said I wouldn't scrap one without a good reason,

    A properly sized bladder tank is the way to go.

    There is no problem using multiple bladder tanks as long as they are piped correctly.

    @samstu , this should solve your problem
  • leonzleonz Member Posts: 126
    edited November 6
    I disagree with you completely.

    You are NOT supposed to use automatic air vents with steel expansion tanks anyway as they will remove all the air in the system and defeat the purpose of the air cushion volume in the steel expansion tank..

    this is why:

    (1) As long as the steel expansion tank has an airtrol valve in the base of the tank and it is plumbed properly,(2) the system filled,(3) the water fill valve shut off and(4) the excess water drained from the steel expansion tank through the vent valve and(5) the vent closed he will have no problems.

    The steel expansion tank will work silently and with no issues unless your system has a leak sometime somewhere.

    "Steel expansion tanks become water logged when automatic water fill valves are used and not shut off after the system is filled and then the tank drained to create the proper air cushion or a new boiler is installed with an automatic air vent by mistake".

    A steel expansion tank works very well and is very effective in removing micro bubbles from the hot water heating system.

    A steel expansion tank properly sized or one larger total volume lets the end user have a low pressure system with much more water
    to aid in heating the home or business.

    I have a B+G 15 gallon steel expansion tank in my system and I wish I had a 30 or 100 gallon tank for my home heating system due to its simplicity and low operating pressure of 4-12 PSIG at all times

    A B+G steel expansion tank with 15-100 gallons capacity can be used with a 3/4" airtrol valve and 3/4" pipe and tapping's and does not require an air scoop BUT one can be used if desired but is not required.
    There is no air bubble noise either once the hot water comes up to temperature to dissolve any remaining air bubbles that float back in to the expansion tank.

    The steel expansion tank simply hangs in the ceiling joists using pipe straps or is laid on a strong shelf and has no rubber bladder to fail.
  • delta Tdelta T Member Posts: 462
    "A steel expansion tank works very well and is very effective in removing micro bubbles from the hot water heating system.'

    Sorry, but no, micro bubbles are removed far more effectively using a modern micro bubble resorber. You are excited about your low pressure of down to 4 PSI. This is giving you a subatmospheric pressure at any point more than 9' 3" above that pressure gauge. This is not something that will work in a lot of systems, causing cavitation, possible air addmittance through packings on valves, etc.

    While I agree with the general sentiment that there is nothing wrong with a properly installed and maintained steel compression tank, it is not a one size fits all solution and there are modern alternatives that function much better in most cases.
  • leonzleonz Member Posts: 126
    I guess you and I disagree. I run my dual fuel coal stoker at summer temperatures with the steel expansion tank and it works very well with the oil side of the system as well with those pressures.

    As much as I despise my baseboard and how poorly it heats my old school house home I have no issues with my steel expansion tank and its use as it was properly installed with the airtrol valve.

    Steel expansion tanks are used in multistory buildings with hot water heating as well.

    AS long as the system has an airtrol valve, the system properly filled then the fill valve is shut off then properly bled through the steel expansion tanks drain vent until all that remains is air they work and work well and what little air bubbles that remain in the system are absorbed and then allowed to rise in the hot water side of the air trol valve where they are released into colder water in the steel expansion tank.

    A steel expansion tank with an airtrol valve has no moving parts and simply hangs in the ceiling joists and simply works with the heat of the system to carry the hot water containing air bubbles upward just like a gravity hot water system would while the hot water is rising into the
    open to air expansion tank and being released to the atmosphere above the water level.
  • STEVEusaPASTEVEusaPA Member Posts: 1,639
    @leonz all comments are welcomed. But you are assuming facts not in evidence.
    1. We don't know what is there currently, the OP never indicated. Could have an old, rotted out tank, undersized, who knows. It's a large system which requires it's own unique circumstances-also what we don't know.
    2. The OP asked if what was being told to him is correct-it probably is, but we're not there.
    3. No one is installing/hanging a new steel compression tank, about 600lbs when properly charged, from the ceiling. If there is an existing tank, and it's in good shape, sure changing the Fil-trol would be easiest. But again, who knows if it ever worked properly.
    4. For ease of maintenance, the bladder tank can be isolated and checked easily. Should they go with your idea, use the steel tank, and close the water feed, besides relying on the LWCO, a system that big and old is probably losing a little water somewhere and you are increasing maintenance.

    Overall, the bladder tank is the way to go, based on the collective experience of everyone who responded, one of those being the top guy in the industry.
    With all respect to you, you're experience is solely based on just one system-yours, and unfortunately, not all your facts are correct.

    Maybe the OP reports back and we get the final results, some pics.
    steve
  • leonzleonz Member Posts: 126
    What your saying is that in my reading of Dans writing is wrong and he is wrong too in describing how his steel expansion tank works?
    The B+G folks have a diagram for the option of hanging multiple tanks of smaller volume in their literature so they are wrong too?
  • STEVEusaPASTEVEusaPA Member Posts: 1,639
    Of course I'm not saying that...Please work on your reading comprehension.
    steve
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 2,840
    @leonz ,
    regardless of what anyone thinks you are entitled to your own opinion.

    But then again so are the rest of us.

    When in doubt.....look around.

    No one as a general rule has been installing plain compression tanks for the last 40 years because,

    Installers like the simpler piping
    they would rather use automatic air vents for air removal
    they dislike service calls for waterlogged tanks and
    leaking gage glass connections regardless if it is related to a bad installation
    A bladder tank is usually smaller than the compression tank it replaces

    Bladder tank installations are less troublesome and more forgiving (in general)
  • gonzalezj618gonzalezj618 Member Posts: 1
    Hello.. I am a homeowner and our house has a Hyteck boiler model BT-18NE with input BTU of Maximum 120,000 and minimum 55,000. A local plumber/heating contractor replaced the The Water Expansion (leaking water).. Now the pilot turns on but the burners won't.
  • STEVEusaPASTEVEusaPA Member Posts: 1,639
    You should start this in a new thread. Maybe Erin can move it to it's own thread, as you're problem is not with the expansion tank.
    steve
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