Boiler makes loud whistle. Sounds like air escaping a balloon.

Jim100Flower

I have new a Laars Minitherm JV225NDISU2 natural gas forced hot water boiler with six zones of baseboard. About ten times a day it makes a loud whistling sound for about 5-10 seconds. It sounds like air escaping from a balloon. You can hear the sound throughout the house and from two floors above. I think it would wake someone sleeping in the basement.
The sound is hard to localize but I think it is coming from the boiler pump. The boiler installer replaced the pump with one twice as big and also lowered the boiler temperature. Both actions reduced the frequency and duration of the whistles but have not eliminated it. Do you have any ideas as to causes and remedies?

clammy

Looking at your boiler pump it looks l8ke it’s on low speed have you tried it on med or hi and what’s the boiler water pressure should be at least 15 psi ,the boiler looks to be piped primary secondary .is the boiler pump pumping into the boiler . Those style heater exchanger require good flow ,the installation manual may show that pumps mounting to pump into the boiler not out of due to the pressure drop across that heat exchanger ,it been a long time since I ve installed one .usually on those type of heat exchanger you will experience noise issue due to low flow ,you should sit down there and try to isolate it to the boiler or system .Also don’t count out short cycling from being over sized .hope this helped peace nd good luck clammy

Intplm.

@Jim100Flower Check the vent above the air scoop. Those things can sometimes make the noise you are describing. There is a little cap on top. That cap should be loose to let air escape from the system. Tighten the cap down by hand. If the noise goes away? You got it.
And also do what @clammy said.

Jim100Flower

Thanks
@clammy Boiler pump is on High and pumping into the boiler. Pressure just above 15 PSI. It is not short cycling.
@Intplm. Noise is not from the cap.

Intplm.

Is there a time that you can anticipate the sound and post a video of it?

icy78

Got any zone valves that could be the culprit?

hot_rod

I'm not seeing a P/S piping? If not be sure any one of those circulators can provide the flow the boiler requires.

JUGHNE

I think I see P/S piping with the pump backwards, pumping into the top of the boiler???

Jim100Flower

@Intplm. Here is a video of a whistle. This is not the typical loud whistle that I can hear from the 2nd floor, but it is a whistle. In the video I turn the pump speed down and then up. It is coincidence that the whistle ends at this point. In an earlier experiment it got louder when I turned the pump down.

https://photos.google.com/photo/AF1QipOGZjwFzksnu7lWNTZBFVuS0Hpy1wMPbQMDUGOS">https://photos.google.com/photo/AF1QipOGZjwFzksnu7lWNTZBFVuS0Hpy1wMPbQMDUGOS

Intplm.

@Jim100Flower Sorry bud. The vid. didn't seem to load. A screen pops up stating the page could not be found. The pictures that you have posted earlier are all that show up.

hot_rod

when copper tube type boilers get scale build up they tend to make various noises. Adding a cleaner or conditioner may help. Chemical Specialists has a product that you inject and leave in to quiet scaled boilers

Does it make the noise with circulatory finning, burner off?

Thst could narrow down a pump or flow only problem

Jim100Flower

@Intplm. Oops - I tried to link to google pics. Here is a link to YouTube
https://youtu.be/M4Tf30JYbio

JUGHNE

I see now that both in and outlet are on the top of the boiler.
Are they clearly marked as such?
Does the piping instructions have the pump pushing into the boiler return or pulling out of the outlet?

Intplm.

Vent damper motor. When you press your hand against it, does it change the sound. Try that and do the some for each circulator. Hold and push each one trying to isolate which one is making the noise.
I'm thinking this is a circulator cartridge that is making the noise but its still hard to tell.

Intplm.

A screwdriver to each one and to your ear will also help.

Jamie Hall

Sounds a lot more like a bearing to me than a whistle... question is which one -- but I'd start with whichever motor and pump it was that changed speed.

hot_rod

Yes, it does sound like a bearing issue now. If the pumps are multiple speed, try switching the speed selector switch to see if the sound changes, that may pinpoint which is the squealer.

Intplm.

@Jim100Flower If you do not have a long enough screwdriver to lean in with as suggested above, go to the nearest big box pharmacy and get a inexpensive stethoscope.(they have them there cheap). Use the stethoscope on each of the suspected noise makers. (Hopefully the noise is only coming from one circ. etc.)

Jim100Flower

UPDATE: I haven't heard a whistle in a week. Yeah! The only change is that we added a chemical cleaner, Silver King. It contains Silicone and is supposed to coat the insides of the pipes and lubricate. I think it also makes the water thicker. Whatever it does, my whistle is gone.
I also checked with the boiler manufacturer and the new boiler pump is the right size.
As a funny side note, @Intplm. I misread your comment and thought it was not helpful. I read it as "if you can't stand the whistle, stick a screwdriver in your ear!" Ouch!

Intplm.

Sorry about that. Would never write such a thing. Seems I wasn't very clear. And I only use a screwdriver now since my stethoscope went missing........👂
Glad to "hear" the noise is gone.

HotanCool

Glad it's solved. I was going to say it sounded like air in the pipes and or a circulator. Still should of put on a better Air Elimination device with the new boiler,than that scoop.

pell

Having this issue with a customer, thought it might be a bearing in the draft fan, can wait to see if the Silver King corrects the problem. He has a Laars and calls it "The Tea Kettle".

pell

Do you remember what Silver King Cleaner you used?

hot_rod

pell said:

Having this issue with a customer, thought it might be a bearing in the draft fan, can wait to see if the Silver King corrects the problem. He has a Laars and calls it "The Tea Kettle".

If it is a Laars copper tube boiler, the kettling sound often indicates scale inside the tubes. It needs to be cleaned with a delimer

A product like this