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Hydronic Noise in Boiler

Recently we have had introduced to our Hydronic system - a noise - similar to a whistling noise. This noise is apparent all throughout the house - where the Hydronic panels are located. When the Hydronic system is activated about 5 minutes into its operation we have this whistling noise through the pipes and panels. Like a plane landing - where the noise diminishes as it goes on. After about 5 minutes - the sound disappears - quietly to nothing... I have bled each panel in the house to try and remove what maybe an airpocket somwhere - however this has made no difference... BUT what I did find tonight - was as soon as the Hydronic system started - I went out to the boiler and just lifted the pressure release valve - this made a squeaking noise thoughout the house and it released water through the copper pipe (attached to the release valve) and the noise was no longer there - much quicker than waiting for the five minutes - each time... So I feel I have the answer - which is located at the pressure release valve on the boiler (outside) however - what can I do to fix this...? Is there an auto release valve that should be working on the boiler and it is not? Anyone in the know - this would be greatly appreciated - and will bring peace to my mornings - instead of putting up with the noise..

Re: Hydronic Noise in Boiler

Why are you running the heating system in July???---do you heat the tap water off the boiler???

A specific noise can be very hard to pinpoint, & can be caused by any one of 10 possibilities:

1) check the psi gauge on the front of the boiler---it should read less than 30 psi when the boiler is running.
2) most systems have an air valve right at the boiler on the MAIN SUPPLY PIPE---this can "whistle" if partially blocked with dirt.
3) if you have hard water in your area, calcium salts often collect at the bottom of the internal combustiion chamber & make weird noises when the flame heats them.
4) a bearing in the main water pump can be on the way out & is squealing at startup.
5) a bearing in the oil burner pump can be on the way out & squealing.
6)there may be a restriction (clogged with dirt) in the fuel line that is causing high cam running pf the fuel pump & a squealing noise.
7) a faulty fuel nozzle on the inner part of the oil burner inside the combustion chamber that's on the way out will often make a squealing noise.

8) etc.,etc.

Since most systems are made up completely of metal piping throughout the house, the noise from one specific area will be telegraphed to the entire system.

It's often helpful to take a short length of garden hose, hold one end up to your ear & try to locate the noise from the other end of the hose as the boiler is running.

Re: Hydronic Noise in Boiler

Thank you for the reply...

July - I am in Australia - and it is cold in July... I should have said this in my post - however that is OK..

WOW - I could not believe the amount of possible causes. I will do as you say and use the hose to pinpoint and see what the cause maybe... I may need a pro - to inspect and resolve - however I will have a beginners go to visually inspect and see what maybe the cause. Thanks again and I will answer the questions below - based on my inspection results.. (all the way from Australia)

Re: Hydronic Noise in Boiler

I would check the pump bearings.

Re: Hydronic Noise in Boiler

They make a vent to keep air out of the system they are called Camvents, Floatvents, etc.. When air gets into your system these will automatically vent out the air. Theses are about two inches in dia. by three inches long and should be located at the highest point in your piping. There is a little nut on the top of these which lets the air out and after a while they rust and become useless. If you have one of these, and I'm sure you do, try to turn the little nut on top, not to much!! It may have to be replaced, easy fix, but have someone that knows what he's doing do the job. Good Luck !!! :)

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