strange noises

PMyers

No zone valves. Each zone has its own circulator, controlled by an ARGO relay panel. Noises occur more often when it is cold out, inside is normally 68 set back to 62.

PMyers

circulator noise?

We have a tenant who hears a gurgle,then a whoosh, then a bang in her baseboard convectors. This is a new system, 6 zones, each with Grundfos circulator, primary secondary, with a Munchkin 199. There is no obvious pattern to this noise, maybe it happens more when it is colder.

Brad White_26

Sounds like

air entrainment followed by water hammer. I suspect it happens when the circulator starts up. A bubble of air is caught in a compromising position at an elbow, fitting or cheap hotel. (Gurgle.) It compresses (vapor lock) then releases as the forces equalize, (whoosh) followed by a slug of water heading to the next hard turn. (Bang.)

I would make sure that the circulators are pumping away from the expansion tank, and that there is an air separator, the obvious good things. I suggest that if you get the air out this goes away.

John White

Maybe too much head? Flat curve may be better. Check it out, don't just assume it's air. People get a bit away from using products designed for American systems, annamored by other stuff.
Just food for thought. jhw

Brad White_26

Could be too much head, yes

but in order for the noise and impact to occur, I would submit that there has to be a difference in density or two media together, as well.

If a consistent gurgling at a high pitch level or tone I would think velocity, too much flow. But the "gurgle, whoosh and bang" leads me to think hydraulic shock, no doubt exacerbated by, as you well pointed out, possibly too much head. A lot of circulators on one system do add up. Wonder what color they are?

Brad White (no relation)

PMyers

These are three speed Grundfos circulators, and the noise happens even on the lowest setting of the pump. The system has been operating for over a year, pumping away with automatic air venting. None of the other five apartments experience this noise.

PMyers

These are three speed Grundfos circulators, and the noise happens even on the lowest setting of the pump. The system has been operating for over a year, pumping away, with automatic air venting. None of the other five apartments experience this noise. Tenant also reports that the noises are heard randomly througout different rooms in the apartment. This is a second floor apartment in a 3 story building. We left the auto fill off for a few days to see if there was a leak causing fresh water(and air) to be introduced but pressure held steady for 5 days. Thanks all.

Brad White_27

Thermal Expansion?

That is the only "Big Bang Theory" (tm) I can come up with. Forces building up and letting go. Does not explain the gurgling and whooshing though.
What is the boiler temperature when this happens? And outdoor temperature for that matter?

Brad

Ed_26

noise

Possibly a zone valve hammering?

Brad White_9

I thought so too, Ed

but Paul says circulators, no mention of zone valves. But you are right, the pattern of progressive noise begs the question.

Paul, might Ed be right in that you may have zone valves AND circulators? Worth checking...