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loud swishing water in baseboard radiators after boiler servicing ( JACKTHESHACK ?)

My radiators had popping and little clanking sounds, minimal bubbly swishing. Kept having nightmares the pipes were bursting... Our utica boilers are from 1983. Saw that the pressure was in the 30's and drained some water hoping to reduce pressure. (we are new homeowners, 2 flat, 2 boilers, learning as we go). One boiler's pressure stayed at 0, while the other was rising into the 60's and we panicked and called a 24 hr heating cooling company on a Sunday and paid $85 for the 30 minute visit.

The guy explained :

our pressure relief valves (don't know the difference between that and a pressure reducing valve after reading this thread..) are the wrong kind (allow for 150 psi vs. 30).

Expansion tanks are too small ( we need a 30), need replacing

One of the feeders(?) had a blockage or was broken, need replacing.

We manually fed water into that one (he wouldn't do it, but allowed us to).

It looked like replacing the parts could be something we could dowith my handy dad, but dad felt uncomfortable doing this in case something went wrong. He referred us to a different guy he used.

Long story short, they replaced:
unit 1: expansion tank, pressure relief valve, air vent, feeder
unit 2: expansion tank, pressure relief valve, air vent

My dad gave him our check and I called the worker as I was not home. He said everything is good except that the feeder valve on unit 2 needs replacing as well as the water keeps leaking into the boiler a little but he didn't have the part then. He told me to turn off the lever (was on for 4 hours at that point). I asked if they relieved air from the radiators in the units and said there was no need, they did it all in the basement (initially they told me they needed access to the units so I arranged for it).

I came home and it sounded like little waterfalls in surround sound all over my apartment. It was very loud. I called and he blamed it on air getting into the system again because of the leaky feeder, and offered to replace it in the morning. I said we'd have to sleep elsewhere for the night as it's REALLY loud and I worried the pipes may get damaged. I was assured the pipes would not be damaged and after some convincing he sent a guy out to get the air out (in the basement boiler room). It did not help. He said they need 2 people for one to bleed the radiators while the other is bleeding the air in the boiler room. I offered to bleed them upstairs but he wasn't responsive. we are up ALL NIGHT.

I plan to be very polite and to trust them, I just want to be educated.

After they drained the system and refilled it, can there be anything else wrong in the system that could be causing this trouble? Could they have incorrectly fed the water back into the system (they did drain all of it)? THe pressure is at 24, winter in Chicago. Is this ok or should be be under 20? Could this swishing around be doing any damage (I worry about sediment getting dislodged and causing a blockage, pipes getting distressed, etc...) Anything I should be on the lookout for?

The airvents look small and different and I want to know that they are working. How do I know if they are the correct ones? Do they come in different sizes/quality? The guy who came later said that the air vent can't handle all the air that's in the system now, but I think I may have heard a quick hiss only once while listening for it. I have no research to back up my suspicion of the air vents,, just an intuition/paranoia.

Any insight, expertise, or experience, would be GREATLY appreciated

Thanks guys!!

Re: loud swishing water in baseboard radiators after boiler servicing ( JACKTHESHACK


It sounds like the repairman may have replaced some parts that didn't need to be, and perhaps should have given you better service.

Are these oil-fired or gas-fired boilers???

It'll take you a while, but eventually you'll find someone in your area that is a good service person, will come over promptly, & solve the problem promptly at a fair price----consult the Yellow Pages under "Oil Burners--Service & Repair" to find a list of independent technicians who will work with or without a service contract (they also service gas-fired equipment); the standard way of having your heating equipment serviced is to contract with a local technician who will come over every fall to clean the boilers, do a tune-up to replace oil filters, nozzles, & clean the boilers---then if anything goes wrong (it almost always happens at the WORST time of winter) the service tech is under contract & is required to come over to fix the problem; this way you can avoid finding yourself in the situation where the system breaks down, there's no heat & you're at the mercy of anyone you have to call to get the system running---they always charge top dollar for "emergency services" in these situations; on the other hand, it may have been that the previous owner didn't do any annual boiler service for some time, in which case it was neglected & almost certain to break down when needed for the coldest weather.

You can also consult the Yellow Pages under 'Heating Equipment---Parts" to get a list of boiler repair servicemen by asking the counterman at some of these parts houses in your area---but the best way is perhaps to take the time to call neighbors, friends & co-workers and ask them for a recommendation for a good, reliable, honest service person that will come to your home promptly & do the job right.

As to your present problems with air in the system----there's no damage or harm that air will cause to the system; but it has to be removed for the system to run efficiently & for the peace of mind of the occupants; there should be a BLEED VALVE on each of the radiators/baseboard that has a little slot that can opened with an ordinary screwdriver (a small number of bleed valves have a special key that fits on a tiny square peg, available at Home Depot); if there are any radiators/baseboard that are situated slightly higher in the flat than the others, start bleeding with those first; hold a small cup under the bleed valve & open the screw valve until you see water come out; when water comes out close the valve & go on to the next bleed valve until all of them have been bled.

WHY IS THERE AIR IN THE SYSTEM: Whenever new water is added to a boiler/radiator system IT ALWAYS HAS ENTRAINED AIR IN IT.---once the boiler fires & heats the water up to 180 degrees the entrained air SEPARATES out of the water and you get the characteristic "waterfall" sound as it is pumped thru the piping/radiators; there is almost always an "air scoop" and main air bleed valve in the large supply piping near the boiler that also expels the air; this has a small adjustable twist screw that can be turned by hand to open & allow air to escape.

INCREASED WATER PRESSURE IN THE SYSTEM: Another thing that happens when the boiler fires up to 180 degrees is that THE VOLUME OF WATER IN THE SYSTEM EXPANDS (WATER EXPANDS WHEN HEATED) ABOUT 4%; thus if you have 15 gallons of water in your heating system (typical) the volume will expand to 15 1/2 or 15 3/4 gallons, this water has to go some where or it will crack the piping----thus the use of an air-filled bladder EXPANSION TANK near the boiler that is always installed on these systems, which temporarily absorbs the expanded water volume (approx 1/2 gallon) until the boiler cools down; if the expansion tank is defective, or some other condition is present to cause more water pressure, there is a PRESSURE RELIEF VALVE that is designed to open at 30 psi to prevent damage to the piping/boiler----it's hard to believe that someone put a 150 psi relief valve on the piping, as the repairman claims in your post; normal system pressures can be read on the boiler gauge on the front of the boiler (there are two needle pointers on a boiler gauge dial: one indicates system pressure in psi, the other indicates boiler water temperature); when the boiler is cold the pressure should read approx 12 psi; when the boiler is hot & firing it should read approx 20 to 25 psi----there is a high limit safety device that shuts off the flame (oil burner or gas manifold) if the boiler temp exceeds 200 degrees; there is a pressure reducing valve (feeder) (set at 12 psi) connected to the house water inlet supply pipe which reduces the house water pressure (usually 50 psi) down to 12 psi, which is the standard pressure all residential boilers operate at in the USA; keeping the pressure at approx 12 psi minimizes water damage in the event of a burst pipe, or other leakage, and also prevents under normal conditions the boiler water (non-potable) from entering the house drinking supply (potable).

Given the age of your equipment (almost 30 years) it's even more important to have periodic service done (at least annually); there have been notable improvements built into newer equipment; an annual service person will be able to tell you how EFFICIENT your boilers are operating at, & for older equipment, typical readings are in the 50% range, which would mean that 1/2 your heat is flying up the chimney to heat the great outdoors----newer boilers can get between 85% to 95% heating efficiency, which would mean considerable fuel savings even just buying an 85% eff. unit for approx $1500-$2k plus installation; if you have natural gas available this will realize considerable savings & put more reliable equipment in your cellar.

Re: loud swishing water in baseboard radiators after boiler servicing ( JACKTHESHACK

thank you so much for the thorough response...

They are natural gas fired boilers.

I did consider new boilers but because we just bought the house and so many other expenses that came with it we have to work with what we have while we can for another year or maybe two until we can spend the money on something more efficient. That is the plan.

The feeder/pressure reducing valve has now been replaced on our unit.

The 2 guys are back today and they have been bleeding the radiators in our apt for over 2 hours now. The water is on in the boiler room that replenishes the water during the bleeding. there are 2 valves in the apt, i think they are 2 seperate loops. They seem to be doing it in no particular order, but are trying to follow through and fix the problem after doing it downstairs did not do the trick. It's hard to say which part of the apt is higher. The problem persists but is better. They said the pipes may not be level throughout the apartment so air gets trapped.

AT this point when they are bleeding the radiators, they are sitting there with 3 cups or more filling them with the steady jet of water that occasional spittles some air out, and doing this repeatedly on both valves one at a time.

Anything I can politely suggest to them that they didn't think of?

Re: loud swishing water in baseboard radiators after boiler servicing ( JACKTHESHACK


I wouldn't want to 2nd guess workers that seem to be on the right track; from your post, it seems like they're doing what they can to remove air from what in most HW systems is a relatively easy task, but they seem to be having problems due to lack of individual bleed valves on the rads, convoluted piping that is catching air pockets, a large convoluted hot water pipe supply system that runs every which way under the floorboards,etc.; it's just a matter of time before most or all the air is successfully removed; once the air is gone, I think you'll be able to appreciate the excellent heat obtainable from the forced hot water system---a heating system I believe is one of the best that exists.

Glad to see you have gas-fired boilers; gas burners are much preferred these days over oil due to the lower cost (in most cases) of the fuel, and its cleaner-burning aspects, which allows the equipment to last longer; Utica makes good boilers; somewhere in the near future, try & get a service technician to do an efficiency test on the 2 boilers to determine if they are operating at 50% or 60% or 70% or 80% efficiency; the higher the efficiency, the less gas that is being used during the winter months to heat the house; you can then make an informed decision as to if you need to replace the boilers sometime in the future by asking the technician that does the efficiency test if he thinks you should keep or replace the boilers.

The sites below offer more info on the air-purging process; in some cases it's as simple as periodically opening the bleed valves on each rad; in other cases, the air is pesky due to the piping arrangement & lack of bleed valves & has to be removed through an air-purging process; if there are no individual bleed valves on each rad, a good near-future project would be to add additional bleed valves throughout the flat.

Another site below illustrates the various & many types of piping systems that are used in HW heating systems; you would have to ask one of the technicians there if he knows which one exists in your flats, or over time you can do some detective work & find out for yourself; the diagrams will help you identify which piping system you have so you understand how the water goes thru the system; the blue box in the diagrams is the BOILER; the RED LINE is the SUPPLY PIPE supplying the pumped hot water to the rads; the ORANGE LINE is the cooler RETURN water being pumped back to the boiler for re-heating.


Re: loud swishing water in baseboard radiators after boiler servicing ( JACKTHESHACK

Thank you for the links, looked over them, will be reading them soon. I really appreciate your advice, and I share your views on energy efficiency. (using mostly led/cfl lightbulbs, motion sensor lights in common areas, energy star appliances, etc..) i will follow your advice.

it's 4:30, and I'm being woken to that sound again like the toilet is running in my bedroom, though it is MUCH better than the first night after their first repair work, before they came back to bleed the system.

My gut feeling, which may have more basis since I first had it, is that the air vent in the boiler system is not working properly /is not installed for efficiency/ is not the best quality… something.. When they left the rads were very quiet, after a long time of bleeding. They did jack up the heat I guess to create more pressure during bleeding at the time. Now it is set to 68. Maybe 5-8 hours later (?), i heard some minor swishing in the front loop, just ignored it. Now, more than 12 hours later, the running water sound is creeping back in when the heat kicks in, BOTH loops. Enough to wake me up and cause my guy to toss and turn. It's like sleep apnea :)

I have a few questions.

1. How can I test that the air vent is releasing air? Any way I can observe it?

2. Have you heard of people not using an air separator that the air vent sits atop, but diverting the air in a different manner with pipe arrangement? Any possible benefit/ disadvantage to one over the other?

3. Are there different qualities of air vents? This one is about $6-8, a 1/8th watts air vent.

4. Could water be leaking out of the system and creating air gaps in the loop? If so, where would it be going? What could be failing? If there was a leak in the walls, would I know?

5.What else could cause that a quiet system gets noisy/swishy as time passes within a 24 hour period? Note that both loops are similarly swishy, and both loops seemed silent for a prolonged period of time when they left.

6. If I turn down the heat at night, that water molecules shrink, right? Where does that air escape when the bleeder valves are not open on the rads? Does it create some vacuum??? Or is that taken care of by the air vents downstairs?

7. Are the 2 loops upstairs sealed off somehow so that they are happy and not contaminated by new air /water entry? If so, at what point? What could be failing?

8. I dont know if the previous owner ever had the boilers cleaned. The techs said if it the air doesn't feel hot in the front, i don't need it done. I'm thinking to do it anyway. Does getting the interior, pilots, etc.. cleaned help anything other safety and prolonged life? Anything that may help the rest of the system work to eliminate/prevent air bubbles/ water leaving the loops?

Thank you for any insight/ ideas. It feels so much better to not feel clueless. I'm a new homeowner and trying to learn, but I'm learning everything at once. It's a privilege to have this resource.

(Here it goes again btw, I'm in a room where the 2nd loop is heating the room, my bedroom is on a separate loop).

I do prefer not to second guess technicians, but I've unfortunately learned to brainstorm and do my own research (TOH, etc). It doesn't always work out right away, and I'd be a really bitter person if I didn't speak up in the past living with floors that aren't sealed properly, skimcoated walls over bulging plaster cracks that weren't repaired first (even after watching TOH videos and specifically asking for some repair work first), but hearing "i've been doing this for .. years and this is how we do it and it's fine". Until the crack comes right back and they admit they didn't do anything to secure the plaster to the slats after all.. etc, etc, etc... :)

I do like these technicians, I trust they are experienced and would probably use them again. I understand they ran into complications that may be hard to troubleshoot. , but at my job I get feedback and have to revisit projects too, I have to question my own approach, it's part of the process. I don't pretend to know more than anyone, so I don't feel I'm stepping on toes, I'm sure you can understand and relate.

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