Hot Water Baseboard Heaters Gurgling

butlerc

Hi there,
We moved into our home almost two years ago and we have hot water baseboard heat. I've heard this type of heat is great and quiet...however...ours is not quiet. Whenever the boiler kicks on and the water starts heating, there are super loud gurgling sounds...not just trickling. Glugging and gurgling, it keeps me up at night. I had a technician come out when we were inspecting the house and he suggested installing an air separator with an auto vent. I had a different technician come out and tell me that that was overkill and not necessary...and that I probably won't be able to get rid of the gurgling sounds because that's just the nature of this type of heat. We live in Ohio and these types of systems are not super common in this area so I feel like I'm having trouble finding an "expert" on this system. I don't want to pay for something unnecessary and not have the noises stop, but every single time it gets cold out, this bothers me. I've watched videos on purging the whole system, but the technician said there was never any reason to recirculate new water or purge the whole system. We have a split level, so a basement with the boiler and then three levels above that. It is a closed loop system with three zones—three separate thermostats. We have a few bleeder valves which were bled a year ago when one of the bedrooms was not getting any heat. We have an expansion tank, and the pressure-reducing valve was replaced last season because it was not the proper one for that system. In addition to the gurgling, the metal expanding sound every time it heats is deafening. I've sort of made peace with that not being fixable, but the gurgling does not seem right.

I guess my question is...do I need an air separator with an auto vent?
Will that solve my issues? Is it normal to need to bleed air out every so often? Here are some pictures:

neilc

where does the expansion tank and makeup water tye into your system?
i can't make it out, but i think you're piped into the top of the boiler,
and the circ is pushing into the boiler,
and that combination is wrong,
you want the circ to pump away from the tank and feed,
look up, search for pumping away here on this site, both as a book, or as articles / threads,

with the boiler and circulator shut off,
do you have an air vent up at your highest radiator, and if you open it does it maintain a steady stream of water or air escaping?
trying to prove proper pressure, and that the tridicator is close to accurate,

are the vents automatic or manual?
if they're automatic they may be drawing air in because of the pumping "to" configuration you have,
try increasing your pressure, 20, 22, 25 tops,
or get the air out that you can with the circ off, then tighten down the vent caps (hope they're all there)

I think i see a way to take the feed from the boiler and connect to that return/valve manifold, where that plug is,
put a vent where the boiler feed is connected now, and add one at the tank,

the tank, should be down, low, so water flows to it, and air doesn't get trapped,
someone put an expansion tank up at the ceiling where the old compression tank was,
wrong location now, and good luck changing it out,

I can't see any venting at the boiler, and or tank,
you could check for air up at the tank line,
the drain there, crack it open and see if that burps water or air, let the air out, keep the water,
do this with the isolation open so you stay live to the system,
be ready to catch some water in a bucket,

post a picture of a rad and its vent