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Trickle Sounds at Baseboard Heater

tony75
tony75 Member Posts: 10
Thanks for reading my post. Nerves are getting frayed here. :-)

I have a boiler system that just passed a clean and check last week. There is one upstairs bedroom on my second floor, one of the furthest from the basement boiler, that has a trickle sound that lasts for several minutes. It is an unused bedroom, so I'm not always in tune with the sounds, but it has been going on for a few months. I thought this was due to air in the lines as it is the most common source of noise in a baseboard system, but I bled the lines today and only got one short burst of air (less than one second - midway through the bleed).

Here are the facts:

1) The baseboard heats well and the room is warm like the rest of the house.
2) There is no moisture related evidence of a leak in the floor, walls, or downstairs ceiling - something I'd be certain to find if this was an actual leak occurring over several months
3) The noise lasts for several minutes (I have set up an audio recorder to get a more accurate measure of the intervals and lengths)
4) The sound is not unlike the tinkling sound a toilet makes when the water doesn't quite stop running (a really tiny flow) or like you are pouring a tiny stream of water into a glass with some water already in it. It sounds very clear (not muffled) and has a certain ring to it that makes me think it is flowing through the pipe.
5) The boiler is 30 years old and I'm not sure the pump was looked at as part of the clean and check.
6) All the upstairs room have some amount of gurgling noise, but they are brief (10 seconds) and don't sound anything like what is happening in the suspect bedroom.
7) The suspect bedroom has a bleeder on one end of the pipes (the top one) and what appears to be a shut off valve (the bottom one)
8) The noise stops immediately after half-closing the valve (not even one or two seconds later - immediately)
9) Today was the first time this baseboard was bled in at last 10 years (probably closer to 20). Same with opening and closing that valve.
10) The baseboard was very hot when I bled it, and started to make the trickle sound before I quit.

Since bleeding the lines today didn't solve the problem, I left a message with my regular HVAC company. I know they are booked through the month, so I may need to call somebody new.

What do you suspect is going on here?
A - A pinhole leak that is quite high up on that pipe and is somehow draining in a way that doesn't show
B - A blockage or significant corrosion on that valve preventing the flow of water
C - An issue with the circulator pump being weak
D - The baseboard needs further air bleeding (is this best done when cold or hot??)






Comments

  • JUGHNE
    JUGHNE Member Posts: 8,686
    If my baseboards have that sound it has always been air.
    The old school method I read of for bleeding baseboards was to turn the tstat up to run the system temp up to beyond normal.
    Get it good and hot and then shut the system and pump off. The longer you wait the air in the system should to up to the high points and then you bleed air. This may work in your case.

    Also what pressure is the system running at?
    For a 2 story you should have 12-15 PSI showing.
    This will push water up to the top of the system.
    If too low then the water may not be pushed to the top of the piping/BB and air may accumulate at the top.
    tony75
  • tony75
    tony75 Member Posts: 10
    edited January 2018
    Get it hot and then shut the system and pump off ---> both of those things are a little murky for a beginner - Would turning the thermostat way down after a cycle be sufficient to turn off the boiler and pump? How would you do this exactly?

    Also, my psi gauge is a steady 15 (I am pointing the Dropcam at it as we speak to determine if any small changes are happening during the day). It was just below 20psi before the clean and check and there was a good bit of water emptied from the expansion tank hung between the basement rafters. The tech said that there was nothing unusual about that.
  • tony75
    tony75 Member Posts: 10
    edited January 2018
    Also, it seems that the sound coincides precisely with the firing of the boiler and ends when it stops firing and the typical short gurgle is heard in another upstairs bedroom.
  • Zman
    Zman Member Posts: 6,792
    Maybe some pictures of the boiler piping.Particularly the tank and air separator.
    My guess is that it is set up with circulator pumping towards the expansion (maybe compression) tank.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    tony75
  • JUGHNE
    JUGHNE Member Posts: 8,686
    Do you see the electric power disconnect switch for your boiler.
    There usually would be one switch that shuts off the boiler/fire and the pump(s).

    Get it hot......turn tstat up to 75 or 80......let run for say 45 minutes.
    Shut it off with that switch. (you do not want the pump running)
    Let it set awhile.......30-40 minutes.
    Go bleed air from every baseboard.....starting on the lower floors.
    Turn tstat to your comfort setting.
    Turn power back on for system.
    This might help.
    tony75
  • Paul48
    Paul48 Member Posts: 4,470
    Because the system is completely pressurized, trying to bleed an individual baseboard can be near impossible. The water takes the path of least resistance, and the air may not be in that path. The only way to effectively purge the air is to isolate the boiler, and use a garden hose to create flow in one direction, through the system, and out onto the lawn. As a friend explained to me.....a no heat call can turn into an 8 hour, 2 man ordeal, with no luck. Try explaining that to a customer. He further explained, that the first thing they do is pump the system empty, and add the necessary valving to do as I described above. Best Wishes and Good Luck
    tony75
  • tony75
    tony75 Member Posts: 10
    Zman - I can post some photos later today

    Jughne - "Shut it off with that switch. (you do not want the pump running)" --> Is there anything involved with turning the main switch back on? I've never touched this switch before and I'm not sure if it affects the pilot light, etc.

    Paul48 - "The water takes the path of least resistance, and the air may not be in that path." --> I'm not quite sure what you mean by the last half of this, but I'm starting to rethink the "normal" gurgle sounds that I hear at the registers. As they can be louder or softer, I think that small amounts of air could be trapped at individual peaks (one side of a 12' baseboard must be slightly higher than the other in an older home).

    So, each time I hear a normal gurgle sound (once at the start of boiler firing and once when the boiler firing concludes), are those both times when water is being pumped into the system? Or, is the first gurgle when the pump starts circulating water in the system continuously and the second gurgle when it finally stops continuously pumping (20-25 minutes later)?

    I think my problem yesterday was that I was trying to bleed the baseboard while the furnace was firing - as evidenced by hearing the trickle sounds as I did it. I think what I will do later today is try again, following jughne's advice, shortly after the boiler finishes a cycle.

    I also think that I can rule out a leak because the sounds coincide with the boiler firing. In a system that holds pressure, those sounds would continue until the waterline was below any pinholes. I'm still stumped as to why one baseboard would have such a weak flow compared to the others. I'm also stumped why that baseboard has a flow valve while the others don't.

    Thanks for your responses, everyone! I so happy I found this board!





  • JUGHNE
    JUGHNE Member Posts: 8,686
    If you have a "standing pilot light" shutting off the power will not shut it off.
    If you have a pilot that lights itself automatically when needed for boiler to fire it will work as before.
    In either case you will have nothing to worry about as far as powering down and back on.

    Paul 48 suggestion would be the proper way to purge IF you have the valves in place for that procedure.
    What I suggested you can do yourself.
    If works for me. (and I do have all the valves in place if needed, but for the baseboard part of my system this was enough)

    Pictures will get you more help/advice.
    Some pictures of the heaters and their bleed valves would be good also.
  • tony75
    tony75 Member Posts: 10
    edited January 2018
    I'll add pictures of those too later this evening.

    I'm definitely more interested in a simple DIY solution, as I thought I had the answer before but it didn't seem to help. Learned a lot in the past 24 hours! Still hoping to learn a bit more about exactly how pumps operate while the boiler is firing (constant pumping or only at the beginning and end of the cycle).

    If I was going to drain the whole system, I'd probably just let a pro do it and have them include some additives while they were at it just for the sake of going the whole 9 yards. Waiting for warmer weather would eliminate much of my risk, so I'll probably go that route unless the place stops heating or a leak is discovered.

  • Peter_26
    Peter_26 Member Posts: 64
    Who performed the "clean and check"? Did they do anything else other than that service? Did you bring up the noise with them and what did they say if you did?
  • tony75
    tony75 Member Posts: 10
    The clean and check was performed by the company that installed the furnace 30 years ago and has done these preventative maintenance appointments every year or two. This time, it was done by a younger guy who I'll refer to as Mr. Short Answer.

    He gave the boiler a clean bill of health. When I mentioned the noises, we went upstairs to that empty bedroom and pointed out that the that the end cap was too low and that the valve was pointed towards the wall. He didn't hear the sounds (I really wish he would have), but he did say that the baseboard just needed to be bled and that water would be added to the system automatically to make up for what I removed. I was able to insert a key into the valve without any problem (although it was a tight fit) and placed the opening of a plastic shopping bag at the valve opening and drain about a pint of water into it. It's too bad I had such poor timing.
  • Zman
    Zman Member Posts: 6,792
    I am still thinking that the air issue is related to the expansion tank orientation. Raising the pressure to it's previous pressure may help. Pictures?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Peter_26
    Peter_26 Member Posts: 64
    I had the same issue and it was both the expansion tank and air scoop leaking. My system must have been running with air in it for a long time because the air scoop was rusted from the inside out. Does the automatic feeder even work, can you hear it run if it needs make-up water? I have a monoflo system and it was rather tricky to get all the air out. What's the pressure gauge indicating?

    There is an infinite amount of experience and advice on this forum but as several have pointed out, pictures are needed. This will give all the experts something to study and comment on.
  • tony75
    tony75 Member Posts: 10
    Thanks for your patience, everyone! It has been a very busy couple of days.

    Here's what I gather from your comments:

    1) send pictures! Will do. I will bring my phone down there later today and upload them in an upcoming post here.

    2) the expansion tank may be a factor. While the maintenance guy did remove some water from it a few weeks ago, tapping on it yesterday sounded as if there was little if any water currently in it.

    3) air scoops have a limited life span. I guess the only way to know if it's rusted out is to take it apart, but the amount of air in the system makes me wonder if it is. At the same time, the system has never been silent and the lines haven't been bled in ages.

    4) listen to hear if the automatic feeder is working. - I'm not sure if it is taking any water in during normal operation. I've actually shut off the water while being away for an extended amount of time and the boiler maintained pressure. Not sure how I can test that (aside of purging a lot of water) or at what point in the cycle I would hear it.

    Here is the current situation:

    The original trickle sounds have diminished. I hate to say they are gone because that would be bad luck, but my recordings aren't picking it up and I've no longer heard it at night.

    The gurgle sound at the start and finish of a cycle has picked up quite a bit in my main bedroom. I removed the endcap from the baseboard (painted and discretely screwed into the wall) and did a bleed a few minutes ago. The first 15-20 seconds was air - although I only gently opened the valve to the barest minimum since it was the first time in decades that it was used. Hoping to see/hear some improvement.

    Air scoops are pretty interesting. I would have thought that they would have been located at the highest point of the pipes to work as intended and not the hottest point of the system as I just learned. I've also read that as the water cools, the pressure actually rises and an amount of air separates from the water.

  • tony75
    tony75 Member Posts: 10




    Using this diagram, I can figure out what most of my system parts are.




    But where is my air scoop??
  • JUGHNE
    JUGHNE Member Posts: 8,686
    The pipe coming out of the top of the boiler with the pressure pop off valve, does it go up to the compression tank?
    Some boilers had a design of air scoop built into the castings.

    If you could find literature for that boiler it would indicate it if so.
    tony75
  • tony75
    tony75 Member Posts: 10
    That makes sense. I figured there has to be some method since the baseboards haven't been bled for so long!
  • tony75
    tony75 Member Posts: 10
    edited January 2018
    Huge improvements here. A brief summary for those researching a similar issue:

    Problem: One baseboard on the upper level was making loud trickling water sounds intermittently. Also, loud gurgling sounds are heard each time the boiler starts. (No issues with boiler pressure or any visual evidence of a leak - just anxiety-provoking noise)

    Steps to solution:
    1 - Attempted to bleed the baseboard in the room with the trickle sounds. Valve was installed pointed towards the wall, so a plastic bag was used to catch the water. Untouched for decades, the valve operated normally though took a bit of strength to budge. I believed that very little air came out because I did it while the boiler was running and the circulator pump was on. I did it a second time later that day while it was off and it was silent after that. (note: The lack of immediate results from the first attempt may have been misleading - see below)

    2 - Unexpectedly, these sounds migrated to a different bedroom. This was a relief because the precise location of the trickle sound was now at a jog in the line and not where the lines descend through the floor - proof that the noise didn't indicate a leak. The bleed valve was near that exact spot and was easily accessible. The line was bled a couple minutes after the boiler cycle was completed - allowing for the water to be hot (maximum separation between the water and air) and the bubbles to settle at the high points. The air released was many times greater than what was expelled in the first room and both the trickle sounds and the gurgling sounds have diminished.

    3 - I monitor a wi-fi camera pointed at the boiler to determine its cycle time and interval. After having some success bleeding that baseboard once a day (a couple minutes after a cycle has completed) and hearing a gratifying short puff of air each time, I have found that it is much more effective in my case to do it mid-cycle while the circulator pump is running and the noises can be heard. I don't hear air escaping, it appears that only water is coming out, and the sounds continue after a cup of water has been collected, but like magic the trickle sounds do eventually stop after a few minutes or during the following cycle!


    Lessons Learned:

    1 - Some people keep their valve keys in the valves! Check all the baseboards before spending time and money on a new one

    2 - A bleed valve that has been untouched for 20+ years is probably still going to be durable.

    3 - While bleeding the lines after a cycle has concluded will allow a satisfying puff of air to escape, doing it mid-cycle seems to be more effective for eliminating trickle sounds- even though there's no immediate evidence that it is working.

    4 - Don't overthink it!

    Thanks, everyone!
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,493
    I think that the old style expansion tanks are piped in such a way as to need no air scoop. The air scoop can remove the air cushion, which is not desirable.
    Some difficult to purge systems have had some Dawn dishwashing liquid added to the system to dissolve the air pockets, at higher temporary pressures.—NBC
    tony75
  • JUGHNE
    JUGHNE Member Posts: 8,686
    Once you have the extra air out of the rads. I would not bleed any more.
    The type of compression tank you have should collect all the air eventually. It air is released in other places the air in the tank will diminish and become water logged.
    Often an auto air vent is installed on these compression tank systems and the tank will become water logged.
    tony75