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Expansion Tank vs. "Fil-Trol"

| Posted in Energy, Heating & Insulation on January 23, 2002 11:04am

*
After servicing our Weil-McLain boiler, the service tech suggested replacing the “fil-trol” tank with an “expansion tank” to be located above the boiler. Is there any advantage to this? What would I use to replace the fil-trol’s water feed valve?

He also suggested that the fil-trol would not allow enough pressure into the system to effectively bleed out any air. This combination of air and the potential of scale buildup results in considerable banging and clanging from the boiler.

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  1. BrianGale | Jan 14, 2002 08:15pm | #1

    *
    Scott,

    Perhaps others can comment, as I am not an expert, but I see no reason to replace your "fil-trol" with an expansion tank, as a "fil-trol" -is- an expansion tank. The fil-trol is a valve on the top of the tank that is operated by the diaphragm in the tank, hence adding water when the system pressure drops too low. Typically, the system should only take on water during the initial fill, and maybe a time or two after that as any air is bled out of the system. If system pressure is a concern, there is a schrader valve (just like a car tire) on the bottom of the tank where air can be added to change the system pressure. If you want 15 psi in your system, the tank should read 15 psi, etc. If you need to add air to increase system pressure, I believe Amtrol recommends you remove and drain the tank first before adding any air. (I've done this on mine before.)

    Scale buildup, water sloshing noise, etc. is due to air in your system. You need the appropriate air bleeding device, like a Spirovent, to remove excessive air. System pressure can help remove it but only to a point. Do you have hot water baseboard or radiant-in floor heat?

    On the previous note, you should have a water supply shutoff valve to your fil-trol tank (also called boiler feed supply, fresh water supply, etc.). If you don't have one, install one. Imagine if your system sprung a leak while you were away- the fil-trol valve would pull in water and continue to dump it all over the house (or wherever the leak is). Bad idea...

    -B

    P.S., as a side note, if your tech doesn't know what a Spirovent is, or can't explain what side of your tank (upstream or downstream) your circulator pump should be on, its a dead give away you need to get another tech. I've been down this road before...

    1. Kerr | Jan 15, 2002 01:39am | #2

      *and when in doubt, ask this question on http://www.heatinghelp.com, the hydronic experts.

      1. Stray_ | Jan 15, 2002 11:59pm | #3

        *Brian,I experienced something similar to your example. The boiler feed (not sure if it's fil-trol or other brand) just got stuck in the open position. Filled my steam boiler full with water, then the pipes, then the relief valve started blowing water into my basement. 3 inches worth before I noticed it.All happened 2 days after I bought the house.....Are you suggesting that one should turn off the supply valve when going away?

        1. Scott_Finney | Jan 16, 2002 01:32am | #4

          *BrianI have baseboard heat, divided into two zones with a pair of Honeywell valves. I have noticed that occasionally I can hear water sloshing and gurgling when the heat first comes on - I have imagined this is a large bubble making its way through the piping.I will check the expansion tank again - I had to replace it a few years back, along with the circulator. The clanging is getting pretty outrageous - I am reluctant to call another tech out - this would be the fifth time and I'm getting pretty tired of "why don't you just replace the whole thing with forced air". I would not be surprised if their is scale in the boiler - I have had to replace every piece of original (35 year old) copper pipe, including 3-inch copper waste due to some kind of corrosion that literally ate the pipes away, brass fittings too.By the way, I have not heard anything from Spirovent, despite several attempts to get info from their web siteKnow any expert techs in the Chicago Northwest suburbs?

          1. BrianGale | Jan 16, 2002 07:23pm | #5

            *Hi Scott-The scale and corrosion problems I don't have any experience with. The noise or sloshing you talk about is most assuredly air, or could be velocity noise (the natural noise water makes when moving thru the pipes but I doubt it.) I have almost the same setup you do minus the zone valves (wish I had them). My boiler is in the basement, and of course naturally air rises thru the pipes to the first floor when filling, and my air seperator is in the basement (so its tough to circulate the air back to it). My fix will be to install a small air purger on the top floor by one of the baseboards this spring. Sorry you are having so much trouble. Sounds like the corrosion thing is quite odd. Go to heatinghelp.com and post a message. Those guys are pretty good at getting things figured out and will help find a good tech. If your current techs tell you to get forced air it means "they don't have a clue what they are doing".Stray-Supply valve should never be left on. A better approach is to have a low water cutoff switch. When pressure drops below "X" preset, the system won't turn on. Allows you to realize something is amiss, go fix the leak or check pressure and refill. The previous owner of our house left the fill on once too and consequently flooded our basement as well when the expansion tank popped a leak. Get the book "How Come?" by Dan Holohan available at the heatinghelp website. Very handy...Good luck-B

          2. Scott_Finney | Jan 17, 2002 08:44pm | #6

            *BrianAn air purger? Sounds good - where would I get some data on those. Is this the same as the little brass can on the top of the boiler?Thanks again, Scott

          3. BrianGale | Jan 18, 2002 05:40am | #7

            *Hey Scott- Probably the same thing. It looks like, well, a little miniature garbage can with a little air valve cap on top. You might try putting one of these on a 90 degree elbow with a stem, and sticking it at the highest point in your system, say on the end of a baseboard. I have a Taco air vent (garbage can) at the highest point in my system, which removes the major air trapped when first filling the system, and I have a Spirovent at the boiler which takes out any little remaining air. One thing you can do when filling your system is close off one of your two zones shut with the zone valve, fill the system, turn the other zone valve on, the one you just filled off, and then continue filling. This will help get the most amount of air out. I have also opened up my pressure relief or drain valve at the boiler, and let it run while doing the filling, just to help get the air out as much as possible.Check out this link...http://www.partsguy.com/heating/boilers.htm and look at the #67 Air Vent. That's a quick picture of that garbage can. Hope this helps- wish I had a scanner hooked up here; I'd just draw how this is supposed to look...Good luck-Brian

          4. The_Tennis_Court_Builder_...on_t | Jan 18, 2002 08:15pm | #8

            *Scott,Here's my .02 cents worth...Fill heating loops with a sump pump in a 5 gal mud bucket...run water or antifreeze solution into bucket and pump in...have return line drain dump into bucket too. run till no bubbles in mud bucket and then close up valves. You will then have an airless fill of your system. Now when you run system...you will have dissolved gases that need to be eliminated. The spirovent works great for them. Bleed vents work too on high points. near the hydronic stream,aj

          5. BrianGale | Jan 18, 2002 08:49pm | #9

            *AJ-How exactly does one achieve system pressure during filling when using a sump pump? You suggest circulating the water thru to achieve the air removal (which by the way I have heard of your suggestion and agree that it works), but then how do you obtain say 12 psi in the system? Usually you get your pressure from city water during filling...Just curious-B

          6. The_Tennis_Court_Builder_...on_t | Jan 18, 2002 10:10pm | #10

            *Brian,There has always been pressurized water available for me. The sump may put out 12 psi too but I do not know that for sure. My system is mainly for checking for air...and for adding antifreeze. The bucket still will show air when city water is used to do the purge.near the eddy in the stream,aj

          7. Scott_Finney | Jan 19, 2002 01:05am | #11

            *So as long as I get the majority of the air removed when filling the tank, and then install a Spirovent (on its way as I write this!)for any dissolved water, I should be good shape.One of the tech's suggested that I may have a small leak that is pulling air into the system. If there is a leak, could that pull air into the system? I would have thought that would cause a loss of pressure, which would then open the fill valve attached to the expansion tank - hmmmmmmThanks to all Scott

          8. The_Tennis_Court_Builder_...on_t | Jan 19, 2002 01:09am | #12

            *Scott,When you add water...you are always adding dissolved gasses that will bubble out of solution under heat. Your Spirovent will help. If you do have a leak, then you may corrode and scale up the system faster than you may like.Leaks should be found if possible.near the stream,aj

          9. Scott_Finney | Jan 19, 2002 02:11am | #13

            *aj,A leak would cause more internal corrosion if it resulted in additional oxygen getting into the system?The boiler doesn't knock right away upon firing - after a couple of minutes, tho, it is really rattling down there. Could the circulator be hanging up as it heats up, boiling the water sitting in there?

          10. The_Tennis_Court_Builder_...on_t | Jan 20, 2002 12:40am | #14

            *Scott...Sounds like your system does have a leak you do not know about or another problem or two. I think it's time to get some estimates and look sees by a local set of eyeballs.near the stream,aj

          11. BrianGale | Jan 21, 2002 04:44pm | #15

            *Sounds like you've had an air problem for a long time that may be causing corrosion problems and its catching up with you. A few years ago a team went to the North Atlantic and recovered many artifacts from the Titanic. The stuff they pulled off the ocean floor 2 miles down wasn't rusted or corroded. Why? No air down there...If you had a leak in your system, you would see a pressure loss. In physics, nature always wants to balance itself. If your system had a leak at 12 psi, it wouldn't be sucking in air. Check your drain valves, ball valves, zone valves, make sure they are not leaking and are shut tight.Make sure your Spirovent is on the hot side (output) of your boiler, your expansion tank can hang on the bottom of the Spirovent (there is a drain plug you can hang it from) and put your circulator pump downstream right behind the circulator (pumping away) from it.Incidentally, may I ask where you obtained your Spirovent (online I assume?)Good luck-B

          12. Stray_ | Jan 21, 2002 06:38pm | #16

            *BrianRE: not leaving the feed valve open...I have a 2-pipe gravity steam system, which is open to the atmosphere (ie steam fills the pipes and the air is purged from the line to make room, every time the boiler fires). Therefore I lose some water vapor via this purged air, and so the system does need to fill on occasion to maintain water level. This may mean the valve opens up for 10 seconds once a week, but I don't see how I can keep the valve shut. Granted a hot water system is a different animal, and H2O loss shouldn't be expected.

          13. BrianGale | Jan 21, 2002 09:48pm | #17

            *Stray-Should have read your post more carefully- not well schooled here on steam- I know very little about it. I would still try to think out some way however that should a sizeable leak of some sort occur it didn't cause a mess. Even a simple water alarm that sits on the ground to sound off in the event of a puddle forming might be nice...they sell them at Home Depot for about $10.-B

          14. BrianGale | Jan 21, 2002 09:50pm | #18

            *Scott-Should have said "put your circulator downstream right behind your Spirovent"....-B

          15. Wet_Head_Warrior | Jan 23, 2002 08:45pm | #19

            *I suggest you go to HeatingHelp.com and ask the pros. Following the advice of someone who has gained all his knowledge from his system and a book is scary to me. Not knocking Brian. But he himself said he doesn't really know what he is talking about. If not done correctly this stuff can kill. Do you really want to follow the advice of a pro or a homeoner when it comes to that level of risk?As far as the guys who have been out there... does not sound like they knew what they were talking about either. The comment about just going to forced air showed they do not know what they are doing and are scared of your system because they do not undertsand it. Ask the guys on the "Wall" at HeatingHelp.com They should be able to help. There may even be a knowledgable pro in your area hanging out there. Happenes all the time.Here is a tip... be humble when you ask for advice. Awhile back a guy came to the "Wall" and asked a vague question. No answer. He then proceeded to rip everyone a new one and questioned their expertise because he did not get an intelligent answer to a dumb question (a dumb question is one nobody can understand)If you post like you have been here you will get the best answers. Good job.PS. Brian... please do not take what I said as a personal insult. You gave it a good try. The way you post makes me think if I needed advice in the area of your expertise YOU are the one I would want answering my question.

          16. Wet_Head_Warrior | Jan 23, 2002 09:08pm | #20

            *Now after reading a post elsewhere I am not so sure about my last sentence. An attitude that "the pros don't know what they are talking about" and "they are all trying to rp you off" and "the pros say you need this and this but I know better" STINKS to high heaven.Maybe that is not what you are saying. If not please correct me and I will apologize. I just see it so often. Then I get to explain to them why the system doesn't work or failed early. Then somehow it is MY fault. I speak from experience.Oh... wait... it is the arrogant DIYers that give me all the good repair jobs. Sorry. I was knocking the source of my livlihood.NOTE... I did not say DIYers. I said ARROGANT DIYers. There is a difference. A homeowner can through diligent study and by asking lots of advice from the real pros learn enough to install a safe heating system that works great. I have seen it and have helped some do it. My real beef is when they then think THEY are qualified to advise someone else on how to do it.Or when they think they can ignore what they are told.Actual conversation..."I know you told me to XXXXXX, but I decided that wasn't necessary so I did it XXXXXX. Now it doesn't work and you told me this is the best way to heat my house."Delivered in an accusing manner. I looked him in the eye and said. "If you are arrogant enough to not listen to a real pro, then want to accuse him when it doesn't work, then I do not have the time to talk to you."Or what about the guy who in a public place ripped me a new one for promoting RFH. Seems he had installed his boiler piping with CPVC pipe and it deformed and leaked. He had used black poly for the tubing because it was cheaper. He has spaced it 1 tube in every other joist to save money. I had spent 4-5 hours explaing how to do it all because he was a friend's dad. He then proceeded to tell everyone there that I was the one who didn't know what I was talking about. That I was ripping people off by trying to tell people to use the more expensive materials.Now understand, I am not saying I have all the answers. That is why I ask questions at the "Wall" too. I go to seminars and training meetings. Shucks, I even get useful tips from homeowners. I guess my biggest pet peeve in life is arguing a ppint from a position of relative ignorance. That is the one sure way to piss me off. Looks like I have some work to do on myself huh? I will work on it.

          17. BrianGale | Jan 23, 2002 10:57pm | #21

            *Wet Head Warrior,Not sure where you read the posts "the pros don't know what they are talking about" and "they are all trying to rip you off" and "the pros say you need this and this but I know better"... I sure don't recall saying that and stand corrected if I did. I did mention in an above post that I should have read one of them more closely relating to steam equipment, and that I didn't know a lot about steam equipment. True, my knowledge (and I did state "I am not an expert") of hot water boilers and specifically baseboard heat has been cultivated by solving problems with my own system, and doing a lot of reading and experimentation. My education as a mechanical designer has helped in many respects too. Notice that for each suggestion I made, I backed it up with either my own experience, a suggestion based on fact, or my best assumption- which incidentally I make very carefully as I would hope others would too.-Brian

          18. Wet_Head_Warrior | Jan 23, 2002 11:04pm | #22

            *Thank you for the correction. My comments were not based on direct quotes, but on what I seemed to see between the lines. I was wrong and apologize for any offence. Thanks again.

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