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Forced hot water making noise

My forced hot water heating system just started making noise this year.
You can hear the water running through the pipes when it first starts kicking in. The system is 4 years old, and it has never done that before.
Any thoughts as to what it could be?



Re: Forced hot water making noise


That's a classic symptom of air in the system---temporarily shut down the boiler by flicking off the boiler on/off switch.

You'll have to start at the baseboard/radiator at the highest point in the system & remove the end caps of the baseboard to find a little bleed valve that can be turned with a screwdriver slightly counter-clockwise to open the bleed valve to let the air out.

First scrunch a wad of paper toweling and place it at the base of the bleed valve & open until you get water coming out & close the bleeder---go on to do all the other bleed valves in the piping you can find.

If you have radiators, instead of baseboard, there is a bleed valve on the top of one side of each radiator that has to be opened & bled of air in the same way as mentioned.

There are a few systems that don't have bleed valves on the rads/baseboard, but most do.

Check the psi gauge on the boiler---you should have approx. 12 psi showing on the gauge---if it's less, there is a water inlet valve that you can open to add more water to the system until you get to 12 psi on the gauge.

Flick the boiler on/off back on.

Please post back to advise how it went.

Re: Forced hot water making noise

I have a similar problem. Had my system completely bled and some solution put in to dissolve sedament. Things were better, but now reappearing. I do have a spirovent which is supposed to eliminate air bubbles. I noticed an oily solution coming from the spirovent and thought perhaps it is clogged and the air is not getting out. My technician did not seem concerned about it. However, I have not heard any air coming out for some time.

Also, my guage is normally sitting at 18 psi. I understand from what I see and read the normal setting should be 12. Could this higher reading be affect boiler and resulting in noise? Help. I am not getting sleep.

Re: Forced hot water making noise


All of the settings you mention may be normal for your system.

I'll assume the noise problem is indeed air for the time being & suggest you try & bleed the air out at the HIGHEST POINT IN THE SYSTEM.

Air always gravitates to the highest point in the pipes & will stay in the system even with a spirovent (usually next to the boiler).

If the tech got some improvement when he was over, see if you can find any bleed valves at the baseboard or radiators & follow the procedure listed in the previous post.

Boiler psi pressure should approximate 12-15 psi when boiler is cold & approx. 25 psi when boiler is hot & has been running for a while.

The "black oily stuff" is usually iron oxide residue from the internal iron parts of the system & is harmless.

Do not allow anyone to drain the old boiler water & put in new boiler water---it just adds more air to the system.

Please post back to advise how you make out trying to bleed rads/baseboards & if you have more than one floor, have rads or baseboard, have an expansion tank propped between the ceiling joists of the boiler room, or a small one that looks like a 20 lb. propane tank.

The "propane tank" style usually has a label that says on it "Amtrol" or "Extrol".

Re: Forced hot water making noise

I too am having the same 'running water' noise throughout my baseboard heaters.

I took your advise and looked for a place to bleed the the zones and found no valves on the baseboard units. Could I have missed them somehow?

I also tried to bleed the zones using the spigots on the returns for about 5 minutes each and that didn't work either.

The highest zone in the house is not getting any heat at all.

I do have an expansion tank off the boiler as well.

Any suggestions?

Re: Forced hot water making noise


On systems that have no bleed valves on the baseboard, these systems usually have a PURGE STATION-type air removal system intead (that uses the spigots).

These systems often have the older, elongated-type steel expansion tank propped between the ceiling joists of the boiler room above the boiler.

To purge air from the piping via the spigots (purge), the boiler on/off is switched off & a short length of garden hose is connected to the spigot & the other end is put into a trash barrel or 5 gal plastic bucket---the 6' washing machine rubber hoses with the screw-on connection, widely sold are ideal for this.

The spigot is opened & the "fast-fill" lever on the PRESSURE REDUCING VALVE is opened to allow water flow into the bucket until all the air bubbles disappear from the bucket.

If you have zone valves, you will have to manually open the valve before you start the purge.

When done, close the manual lever if you have zone valves & turn the boiler on/off switch back to on.

Pictures of these valves are at the site below---click onto "homeowner", then onto "valves" then onto the particular valve--also click onto "tutorial" for more photos & info.


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