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Why Hoffman #4s make clicking sound

Hi All
I have been working to understand whether the amount of make up water used by my brand new (April 2018) Burnham Independence (IN8I) --245 BTU/hr --one pipe system with 13 radiators (there are also 2 small ones in bathrooms that are off). The new boiler has an auto feed with a gallon counter.

All return pipes are exposed, and there is no evidence of leaking. Ditto on the visible supply lines. Ditto on the radiator supply valves ( i put glasses over the valves to ck for condensation)

Last Spring, just after the install, it was still cold, and the boiler was used for about 5 weeks--it used 3 gallons in that time--so I figured there was a problem.

I found that the mains were letting alot of steam out. So, in October, I replaced them with Gorton #2s (there are 2 mains on either side of the house). That seemed to help, but the make up water went to 5 gallons after about 2 weeks in late october.

So, I replaced all the radiator vents--someone had installed verivalves on all radiators--and I put shot glasses over them, and found a significant amount of condensation during a cycle--so, I replaced all of them with what was the original valve for the system --Hoffman no 40s--i know this because the person left the old valves in the enclosures--so I bought brand new ones.

I did the replacement 2 weeks ago--it has been cold, and the system has been working. It now appears to be using about 1 gallon of make up water per week.

I will ask for thoughts about that 1 gallon in a moment. First, my question about the "click" noise the new Hoffmans make---one thing to note--in case anyone out there has hammer noise in a steam system --mine has absolutely horrible for clanking, and hammer--it totally, 100% disappeared with the new Hoffmans--so, if you have that issue, you may be venting too fast.

Anyway, the system works great--radiators come to heat fast, no hammer. However, late at night when the house is very quiet and the steam is on, I can here all the valves periodically making a light, metallic "click", and then I hear gas hissing (escaping)--then the click happens again and the hissing stops--all the valves do this, and they do it multiple times during a heat cycle. It is like a symphony of clicks.

Why do they do this? I assume they are venting air--but why do they close, wait awhile, then vent air? Why doesn't all the air vent, then close when the steam arrives? I am wondering if they are only venting air--and whether the hiss could be steam--remember, these valves are all brand new, so I doubt they are malfunctioning. I haven't had time to use shot glasses to see if steam is venting, but i am assuming they are new and working right.

Anyone know how these things work, and why they'd open and shut multiple times in a heat cycle?

Now onto the makeup water rate of 1 gallon a month. I am well aware of Burnham's anxiety producing chart in its documentation that indicates that a service person should be consulted if an I8 boiler uses more than 3 gallons in a season.

Note that it DOES NOT say that using more than 3 gallons a year is a sign of a problem. All it says is that a service person should be consulted to check the system for leaks.

Burnham is shamefully ambiguous on this point. The manual indicates that a "leaky" system can drastically shorten the life of the boiler--but, it gives ZERO definitive guidelines of how much make up water is too much.

All they tell you is to check for leaks beyond a given threshold for the boiler size.

So, I have done that in spades--there are no leaks on my system (I suppose it is possible a pipe in the walls is leaking, but that seems unlikely to me, given they are vertical and drain completely).

To put my usage rate in perspective: 1 gallon a week / 13 radiators = 9.84 ounces of water loss, per radiator, per week. So, per day, that is 9.84 ounces / 7 days = 1.4 ounces lost a day per radiator. Now, lets say the steam comes up 1x per hour. So, 1.4 ounces/24 cycles in a day = .05 ounce of loss per cycle. These are ballparks, obviously, but they do put the loss in perspective.

So, think about that.--- .05 of an ounce per heating cycle, for each radiator in my system equates to 1 gallon of makeup water per week. If you put a shot glass over the radiator vents, I am confident you will find a properly functioning vent lets that tiny amount of water escape on a given heat cycle.

So,, am I correct to conclude such a rate of water loss is "normal", and not indicative of a "problem"?

So, what do you all think about this? If I take the Burnham documentation to heart, I will worry I am using way too much make up water. But, based on the above calculations--it seems to me Burnham is creating unnecessary confusion about whether "normal" make up water is nothing to worry about. Given the above calculation on the per radiator loss of my system , it seems ludicrous to think a 13 radiator system could function and lose only 3 gallons (or less) per year.

Any thoughts?


  • ImYoungxDImYoungxD Posts: 120Member
    edited December 2018
    The air vents open and closes because the radiator condensates and the cool air needs to escape to bring in more steam.
    Or your pressure is too high and the air vent can't handle the pressure.

    I have a couple of hoffman 40s and they do the same.
  • coelcanthcoelcanth Posts: 62Member
    what does the sightglass show you ? where is the water level in the boiler during the heating cycle and where is the level when it's cool ?

    i had problems with dirty water in my new boiler, which made the waterline surge drastically, which would trigger the LWCO, and then the autofeeder would overfill, which in turn exacerbated the issue and continued the cycle...

    if you are relying on the autofeeder and not filling manually, i might guess you don't actually need so much makeup water, and it is being added in error..

    i was able to resolve the issue by carefully skimming the boiler and monitoring things while only adding water manually.

    are your 13 radiators absolutely massive ? your boiler sounds quite large.. maybe that is part of your vent sounds, if related to pressure
  • KC_JonesKC_Jones Posts: 4,100Member
    dkirkwood said:

    So, think about that.--- .05 of an ounce per heating cycle, for each radiator in my system equates to 1 gallon of makeup water per week.

    That would be 85 ounces of steam per heating cycle per radiator, remember steam is 1700 times the volume of water, it doesn't sound so insignificant when you put the proper perspective.

    If you are trying to justify 1 gallon per week or 20-25 gallons per year as normal or acceptable, I for one am not going to back that. 20-25 gallons per year is crazy high, you should be looking at the 3 gallon number more seriously.

    Steam leaks can be very difficult to find as it just absorbs into the air and the steam is invisible. I am not on site at your house to see what's going on I only know the things I have done to close up my system. 1 of those things was repacking every valve in the house, that was the biggest water usage change I saw. Also I feel running very low pressure (a few ounces) helps a lot, this can also have the added benefit of quieting those valves down.

    The clicking is relatively normal. Once the vent cools it opens, then steam hits and it clicks closed, lather, rinse, repeat.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Jamie HallJamie Hall Posts: 10,303Member
    I'm not sure we scare folks with some of our comments on adding water. I'm not advocating a lot of water, but I would not say that a steady rate somewhere around one gallon per week for a 400,000 BTUh boiler in cold weather would be excessive. Warmer weather that should go down, and, of course, with the boiler off it should be zero.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • mikeg2015mikeg2015 Posts: 770Member
    I think for many leaks you need a good IR camera to pick them up. Best if you let the house cool off first for more contrast.

    What I do find is that early in the season I was adding at least 2 gallon a week on a 375k input boiler (20 gallons). But the last 2 weeks haven't added any, it's held steady just above the normal line.

    My theory is that the radiator valve stems packing swells a little and a few pinhole leaks seal themselves up. Some vents might have been leaking initially, and have reseated a litlte better after inital debris worked itself out.

    Every year I limp it along is a bonus in my mind. The oversized boiler turned 35 and there were a ton of steam leaks that just needed threaded tape, a packing nut tightened a little, and new gauge glass seals for $7. They must have been adding 3+ gallons a week before I fixed everything. 14 radiators, so 14 valves, 14 unions, 14 vents, and I count about 150 push nipples for all the radiators and boiler sections. They all can leak.
  • FredFred Posts: 7,816Member
    The newer Hoffman vents do click when they open and close. They pretty much always opened and closed during a heating cycle, but the clicking makes it more noticeable.

    As to the water usage,
    has this boiler been skimmed? Did they install a skim port? What is the pressuretrol set at? It should be .5 Cut-in and the Differential (white wheel inside the Pressuretrol) should be set at "1". Even though you installed new Gorton vents on the Mains, are you sure they are fully closing when steam hit them?

    Do you have any radiators shut off? If so, steam may still leak past the supply valve but condensation may not be able to return to the boiler.
  • dkirkwooddkirkwood Posts: 20Member
    Well, I found a significant leak, if not "the leak"--I update this in hopes it helps anyone else pondering make up water issues.

    Although I had looked a the supply valves, I missed the leak. This past weekend I put glasses over all the valves again, to determine which showed any condensation, to target them for replacement.

    That's how I noticed a drip on a supply valve that is mounted sideways--the valve stem is horizontal, not vertical. The drip fell into the hole where the supply pipe comes up--that is why i never noticed water.

    So, i put a dish under the drip. To my amazement, I collected 18 ounces in 18 hours--that amount of loss correlates almost exactly to the amount/rate of makeup water being added.

    I repacked the valve yesterday--and so far, not a drop. I will update in a week or so to record the impact the fix has had on the make up water.
  • dkirkwooddkirkwood Posts: 20Member
    This is the promised update--I hope this helps someone out there wondering whether an old steam system is adding too much make up water.

    While my logic in my first post was "logical" in that the amount of water loss from boiler spread over all radiators did not seem like much, and therefore "normal", I could not have been more wrong. The fallacy of my premise was dividing the loss over all radiators--if you divide it over one radiator (or leak) it is a totally different conclusion in terms of severity.

    It has been 4 weeks since I found the leak and repacked the faulty valve. The meter on the boiler that measures make up water has not budged since. And, the day I repacked the valve, I know the boiler had lost at least 1/3 gallon since the autofeed had last registered a new gallon of input. I know this because the day I noted another gallon of input on the meter, is the day I found the leak. I put a dish under the leak and collected the water for 24 hours, then measured the loss (to confirm the severity of the leak). So, even starting with a significant amount of loss, the make up water has not yet been enough to register a gallon of input since the repack of valve.

    In other words, it appears Burnham's 3 gal/season makeup water specification as the limit for "normal" for my boiler is accurate.

    If you are fighting the same problem on an old steam system, don't overlook the radiator vents--I think replacing them back to the original hoffmans (getting rid of the quick vents) made a huge difference in the overall performance of the system, and also helped retain water.

    Having been in the house 18 years, I can say the heating system has never functioned as well as it is now--so i hope this saga helps someone
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