Hydronic boiler - whooshing sound when boiler "closes:

RickHowland

System: Utica 15B boiler. 2 zones. Feeds zone 2 first, then zone 1. Zone valves Taco Z075c2-1. Grundfos Alpha pump, set to Auto (with one zone open usually runs at 1 GPM, 9 watts, both valves open highest it hits is 13W). Spirovent vent, Amtrol Tank (6 months old).
2 story home.
You can hear (pretty loudly) a whooshing sound of what seems to be like water turning off, when call for heat stops. I run to the boiler when I hear it and both valves are closed. At first I thought it might be happening when both valves are open and one closes that it caused the sound. But today when I ran to boiler both were closed. Tried to recreate sound by turning one thermostat on, other closed, ran a cycle, but no sound. Tried both open, calling for heat, then closing one or the other (tried both ways of turning off one zone first, got nothing so put both back on, then closed the other, no sound). This sound does NOT occur every heat cycle, but we hear it 2 or 3 times a day. The "whoosh" lasts about 2 seconds, heard on both floors but mostly directly above boiler.

I'd call a tech but I don't see how he could recreate it, when I can't, and it does not happen every time.
Help .

hot_rod

Try putting the pump in another setting, see if it stops. The auto adapt may not be adapting quickly enough?

EBEBRATT-Ed

also check the water pressure in the boiler should be 12-15 psi cold and around 20 when hot

rick in Alaska

This is also assuming the pump is wired in such a way that it shuts off when the zone valve does. It sounds like what might be happening is that the pump is still running when the zone valve shuts down, which can cause that kind of sound.
Rick

SuperTech

What side of the system are the zone valves installed on? Is your Alpha circulator setup so it's constantly energized?

RickHowland

I'll answer all questions: Water pressure is good, never above about 17 or 18. It was mentioned the pump may still be running when the valve closes. That is exactly what happens "normally". There are 2 zones. So yes the pump may be running and both valves may be open at the same time. Then one valve is "satisfied" and closes and the pump runs because the other valve is open. Now, I do see that if one valve is open, then closes, the pump still "runs" for a few more seconds as it shows the number of watts declining then shutting off. I was asked which side the zone valves are on, they are on the "out" side. I was asked if the pump is constantly energized? I do not know how to determine that.
I try to catch what is happening as far as when it happens or does not happen. But short of camping out at the boiler for hours it is hard to catch. When I hear it, I run to the boiler to see what is open and what is closed. MOST of the time it appears that it happens when one valve is still open, but the other is closed (just closed), but I have seen it where I run to the boiler and both valves are closed.
(I am keeping fit running down to the basement, up to first floor, then up to second, then back down, etc.).

Ironman

Pictures please. Of the boiler, pump, zone valves from far enough back to encompass all.

MikeL_2

Rick,
        I had a customer with a similar issue - taco zone sentry zvs. It took many hours on site to catch the problem in real time.
        The circulator for all zones was on the supply, and 4 zvs on the return at the boiler. The intermittent whooshing noise was heard in the dining room. The dining room was on the opposite side of the house from the basement boiler room; about 30 feet away.
          The problem went away after switching to Taco 570 series zvs, a much slower closing valve......

HomerJSmith

The Alpha is constantly energized when the cord is plugged in to an electrical outlet.

rickhow

Answers to recent posts: I post photos are requested tomorrow. The pipe comes out of boiler, then Alpha pump, then up, makes a left over to a joint (hanging from joint is expansion tank, top of joint is spiro vent, then goes to zone 2 valve, then zone 1 valve. through to baseboards, then two returns (zone 1, 2) to individual ball valves, then back down to boiler.
Mikel, I too thought it had to do with zone valves, but was thinking as the valves are 5 years old that they were closing too slow, so thanks for the tip that valves may be too "fast". I too have yet to catch the problem in real time to see which (or both) valve is causing the problem.
About pump being constantly energized. The "cord" (in sheath) comes out of pump into box hanging on side of boiler (which has led display for service codes, and contains electrical wires to the pump. Out of that "box" comes a cord (in sheath) to transformer, then transformer to wall outlet. The pump has an led display which show how many gallons per minute and how many watts are being used when it is on. When not needed (pump not running) the display is black. no lights.

hot_rod

Which operating mode is the Alpha in?

rickhow

It is set in Auto Adapt.

hot_rod

Maybe try one of the other pressure settings, see if it slows down the flow quicker?

Ball valves stop flow by shearing off the fluid stream. When the gets down around 80% shut down, they present a crappy flow path across the two edges of the ball. Under high flow conditions that could be where the noise is starting.

Noise at any type of zone valve often indicates excessive flow.

Assuming it is a standard ball inside? They do build characterized balls for more precise fluid control, balancing for example, Bellimo and others.

rickhow

I will do that. I watched a few videos on Youtube on this pump (specifically my model) so it is easy to try some different settings. Thanks.

rickhow

Isolated the problem. Keep in mind the water (out) first goes through zone valve 2 (2nd floor), then feeds zone valve 1(1st floor). I turned up both thermostats so both valves open. Running nicely (Alpha pump indicates 3 GPM, 13Watts). I then stood at boiler and had my wife down 2nd floor, leaving 1st floor running. When the valve closed for 2nd floor (1st floor still open), I got the sound. Alpha dropped to 1gpm, 3Watts. I then reversed the process, leaving zone 2 (noise valve) open, closed first. did NOT get the whoosh sound. Third try I just operated 2nd floor only. Got the sound.
So, it is the 2nd floor zone valve. Either closing too slow or too fast and causing the "woosh" sound.

Redrum

Hi Rick;
Please see my started thread - https://forum.heatinghelp.com/discussion/157729/hydronic-system-whoosh-noise/p1

Note that I am not a pro, I am a homeowner, but have had hydronic heat all my life, so at least a "little bit" knowledgeable.

As you can see from the thread, the kind people here had allot of ideas on how to resolve. I never did fix it, mostly because I waited until summer, and I spend 80% of spring through fall away from home. I guess I just lived with it.

I never had the sound with my old boiler - Weil McClain with Honeywell valves, but with my new boiler - Buderus with Taco valves (feeding 1" to 3/4" zones), it "might" have been there, but when I added a 1/2" fed panel radiator as a new zone, it showed itself.

I can manually close a valve with another open, in fact, pause halfway closed, and whooosh...

People recommended I switch the pump to a delta P, and I intended to do so (summer thing), but my head says it's cause by the valve switch from honewell to taco (as recommend in my thread).

Just thought I'd show you the thread, maybe something is relevant to your issue

From your last post, is the troublesome zone a different type of valve or a different piping size?

Jim

RickHowland

Solved! Called a tech out. He could not figure it out. In my frustration I went to the Taco Website and sent a note to their Tech department. Recall the zone valve I had was a Taco Z075C2-1. They answered that they do know this valve sometimes in various applications can cause such a sound. It is due to closing too fast. The recommended I replace the Actuator head with one from a model Z075C2-2. Just remove the actuator head and swap in the head of the c2-2. A simple snap off and snap on no need for any "plumbing" activity nor need to replace "brass". I sent for it today on Amazon.

Redrum

Thank you for posting this, I have the same ZxxxC2-1 (I have 100 = 1" and 075 = 3/4"). So, when you say "solved" have you tried it yet, or are you waiting for the actuator from Amazon?

Jim

rickhow

Good point...I have not tried it yet...but I'm having faith that what Taco rep told me is the cause. Because he said it is a know thing that happens sometimes with these valves. I post actual results.

Redrum

Great, thank you for posting what you find out. From the previous link I posted, I (along with the supportive forum members) worked on trying to solve it for a long time, until I finally gave up and just lived with it. If it works for you, that would be great to know.

I believe it may, one of the forum members that works at a hydronic valve manufacture thought my problem started with the new boiler install, which eliminated the old honeywell valves and replaced them with taco. He said (paraphrase) that the closure mechanic is different, there is some compliance to the way that the honeywell close. Since a valve swap for me is a big deal (5 zones) I put it off "until summer" and then of course, it no longer made noise Like I said, I just have been living with it.

Thank you again for posting
Jim

rickhow

I will post results next week when I get the valve. I have 2 valves but only replacing one (didn't want to pay for 2 if this is not the problem). Price range for the exact same part was widely different at all different suppliers. Cheapest $112, most expensive $181. Most were "plus shipping and handling". I went with Amazon as it was only a bit more than the cheapest place, bur free shipping, and no haggle returns so I can return it if it is not the fix.

rickhow

Still working on it. Replaced the head on the valves with those I ordered from Amazon. No change at all.
Purged entire system, was some air, now no air. No change at all. Today I am replacing the Taco valves with Honeywell.

Redrum

thanks for the update, how disappointing for you. I'll be interested to hear how you make out with the honeywell. Like I had mentioned, I did not have the sound until I replaced my boiler (and the valves - honeywell to taco), but all my zones were 1" (reduced to 3/4" at radiators), and when I added a 1/2" for a panel radiator, the woosh got real apparent. So I don't have experience with 1/2" and the honeywell valves.

Jim

rickhow

FIXED!!!! Replace the TACO with the Honeywell and my system is totally quiet. Purged every ounce of water out and refilled too (purged air too). The Honeywell valves did the trick. No more Taco for me.

Redrum

good to hear. which honeywell valves did you use?

rickhow

Honeywell valvs V8043F1036. Looked locally at supply houses. Prices averaged around $300 each (solder on style). I looked on Amazon and got them for $106 each, free delivery. They also had it listed as "Amazon's Choice", but this was MORE money for $126.95 each. There were also quite a few listed for $112 each. Down the road if the valves need, for example, a new motor, you can buy it on Amazon and replace it without have to disturb nything to do with the water, ball valve, etc. Or also get an entire head replacement. I had Honeywell on my first boiler and they served me well for many years. They are not as fancy looking as the Taco, but what good did fancy do me. Taco may have nice LED lights, nice shape and colors, but never again for me.