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MasterPlumbers
We’ve problems with a termostatic valve designed for house heating circuits. It begins chattering when it is near to be closed. If someone knows which can be the causes for this noise…
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The chattering is due to high velocity through the valve. A globe valve before the chattering valve for the purpose of reducing the quantity of water to the minimum required for the circuit may stop the chattering.
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Harold I am appalled PLEASE re read this question.
As Experts in HVAC we both know of a condition called “hunting” when a thermostatically controlled device is “hunting” prior to fully closing or opening.
We know from experience that the set point is not always reached and the controller seeks (hunts) to do its job.
This chattering is a classic example if a controller that needs to have its actuator replaced or re calibrated
The Globe valve although used for “throttling” is also going to give a much higher friction loss and thus impede the actual flow of the hydronics.
What I would have suggested it to remove the actual controller and go back to a manual COMFORTABLE setting using a manual setting with the original plastic cap normally supplied.
When we work with pneumatic and electronic it can become tricky setting the actual desired set point with a manual set anticipator like the older Johnson controllers with master and sub master stations or the Good OLE Leslie steam stations.
The easiest fix is to just leave this valve in the N. O. position for fail safe setting.
Have a Happy and Healthy New Year and keep on posting.
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Yes, Sylvan. I understand your reason for assuming that this person’s house has a Johnson controller with master and sub master stations or the Good OLE Leslie steam stations. New York City homes are often over 5000 square feet built before insulation was fashionable and may have these devices.
At the moment, we don’t know what this person has, so it is a best guess. Does the ‘termostatic valve’ have a plastic cover? Did Sylvan guess correctly? If the person has a balancing valve of some sort before the valve, he may reduce the noise by reducing the flow rate.
Will opening the valve adjust the heat in the loop or the room? Or will it make the rooms overheat? Tune in for the next installment.
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quote:
Originally posted by Harold Kestenholz:
Yes, Sylvan. I understand your reason for assuming that this person’s house has a Johnson controller with master and sub master stations or the Good OLE Leslie steam stations. New York City homes are often over 5000 square feet built before insulation was fashionable and may have these devices.At the moment, we don’t know what this person has, so it is a best guess. Does the ‘termostatic valve’ have a plastic cover? Did Sylvan guess correctly? If the person has a balancing valve of some sort before the valve, he may reduce the noise by reducing the flow rate.
Will opening the valve adjust the heat in the loop or the room? Or will it make the rooms overheat? Tune in for the next installment.
Harold my home is approximately 7,400 SQ. Ft with 20+ Cast Iron Radiators some as much 24 Sections 3 tube 22″ high and ALL these radiators have a NON ELECTRIC zone valve connected
What I did do is use various manufacturers to test which valves not only held up the longest BUT which ones were trouble free.
Some of these valves are over 20 years old and TWO valves did have “hunting problems” from the giddy yap (GET GO) Day installed ETC.
Even when I did replace the valve actuator they still hunted /CHATTERED causing a hydraulic shock wave back to the HB Smith rock mills boiler GREAT BOILER by the way.
Even when I removed this 13 section pork chop boiler and installed TWO gas fired boilers in its place (I love redundancy) the chattering continued so I just removed the actuator completely and end of problem.
Many, many times I install a non electric zone valves to fine tune a system instead of using CRAP electric zone valves or high priced circulators for each zone with related fittings to prevent unwanted circulation.
These valves if properly utilized cannot only increase comfort and fine tune the system to make up for the original installers mistakes in sizing it also allows for huge fuel savings.
The old fuel bills were over $800 per month NOW 12 years later using two boilers and running gas as opposed to cheaper more efficient Oil my average cost per month is hovering around $425.
So you see Harold I don’t have Leslie valves and electronic or pneumatic controllers like one of my accounts has, A ONE family home they have over 18,000 SQ. ft to heat with Cast Iron base board and radiators and Scorched air for the main living room with 4 air handlers to boot (a nightmare to service) PLUS they do have pneumatic controllers on the supply and return headers.
Want to see it let me know on the PIPDL.
IM serious if you want to see everything possible in ONE heating system this is a must see considering it is a ONE FAMILY home with a monthly heating bill exceeding $1,400 per MONTH[Edited by SylvanLMP on 09 January 2001]
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Sorry, but it has been impossible for me to reply to your answers. I’m up to my eyes at the moment.
I work in Spain and we’re trying to redesign a thermostatic valve, because we want to sell it in England. But our valve doesn’t work as well as we expected because of this “valve chattering”. I didn’t know what this meant and what causes it.
The valve is pneumatic controlled, with no electronics. It begins chattering in a working point, as I told before, when is near to be closed. At this point, the water flow is 50 l/s. The valve must work correctly by itself. So, a globe valve before our valve is not the right way.
Our problem is to guess the reason of this valve chattering. We have three possibilities:
If the chattering is due to high velocity through the valve, the pressure can fall down the saturation pressure. This could be cavitation.
Some kind of vibration can cause resonance with the spring.
Finally, water hammer is our last option. But this is often caused when you close a valve quickly and you have a large mass of water.
Weave measured the noise. It’s too noisy to be cavitation. With the frequency we’ll be able to say if it’s some kind of resonance or water hammer.
What do you think about this? Could you think of any new reason for the chattering?
Thank you very much. Happy New Year. -
quote:
Originally posted by [email protected]:
Sorry, but it has been impossible for me to reply to your answers. I¡¦m up to my eyes at the moment.
I work in Spain and we¡¦re trying to redesign a thermostatic valve, because we want to sell it in England. But our valve doesn¡¦t work as well as we expected because of this ¡§valve chattering¡¨. I didn¡¦t know what this meant and what causes it.
The valve is pneumatic controlled, with no electronics. It begins chattering in a working point, as I told before, when is near to be closed. At this point, the water flow is 50 l/s. The valve must work correctly by itself. So, a globe valve before our valve is not the right way.
Our problem is to guess the reason of this valve chattering. We have three possibilities:
„h If the chattering is due to high velocity through the valve, the pressure can fall down the saturation pressure. This could be cavitation.
„h Some kind of vibration can cause resonance with the spring.
„h Finally, water hammer is our last option. But this is often caused when you close a valve quickly and you have a large mass of water.
Weave measured the noise. It¡¦s too noisy to be cavitation. With the frequency we¡¦ll be able to say if it¡¦s some kind of resonance or water hammer.
What do you think about this? Could you think of any new reason for the chattering?
Thank you very much. Happy New Year.
Thank you sir for CONFIRMING my Assumption it was PNEUMATICS.
“The valve is pneumatic controlled, with no electronics”
The problem associated with this type of modulating action is as follows.
Electric valves are either NO or NC
Electronic and Or Pneumatic are modulating and thus can cause a “hunting effect” chattering.What you can try is reversing the valves action as follows Have this valve in the normally OPEN position and using the “controller” to close the valve when the desired SET POINT is reached.
The beauty of having a Normally Open valve is in this fail safe mode you will have constant circulation thus less chance of freeze up.
As a chief Stationary engineer I used to Calibrate these types of valves and if you adjust the air pressure you can eliminate the hunting.
Double check your set point to the actual travel distance on the actuating piston or diaphragm.
You may also want to increase SLIGHTLY your orifice to over come the possibility of excessive velocity especially during valve opening or closing.
What I did when installing steam stations (high pressure 125#+) was to use several step down valves prior to using the steam to heat domestic hot water and absorption systems for my Air conditioning Environmental Controls.
If your having problem controlling various valves do to different application / pressure /volume needs try adding slightly more resistance to the piston assembly VIA higher tension springs etc.
Unfortunately after I turned 27 I no longer found heating that interesting and thus gave away all my heating testing equipment BUT what you could try is set up a test bench like I did when repairing these devices and put a Gauge on either side of these valves and test for the following.
Charge the system and then modulate the valves like under system demand and see when the chattering starts WHAT pressure then you can try a slower closing valve design like we used in the Navy on flushometers a Naval flushometer like a Sloan type that uses hydraulics.
Too bad your so far away as It would be fun working this kind of problem out.
I had something like this going on in Rhoda Spain at a Winery BUT those were the days I worked cheap and didn’t mind traveling
This winery was trying to maintain an exact temperature for the wine.
Ah those Benefits working in the big vats .I am sure your problem can be repaired by simply hit and miss with the valves opening sizePLEASE feel free to Private E mail me again. Sylvan
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You have a complex problem. If you will eliminate controller harmonics by closing the valve slowly with a screw instead of the pneumatics, you can concentrate on the valve shape. If turning the valve closed with a screw does not produce the problem, then the noise is due the controller.
Pneumatic/spring control is problematic in that powerful fluid dynamics have to be overcome with resonant chambers and harmonic lengths of metal.
Double-diaphragms with fluid trapped between and the fluid passing through a motion-dampening orifice gives greater control than a harmonic spring-resisted air chamber. Zone valves here using wax cartridges in metal pistons have shown durability without resonance.
It is interesting to know the application of this valve. Fifty liters per minute provides a heavy column of water with strong inertia. Providing 120,000 btuh or more with one valve is unusual for a residence. That translates to a 4800 square-foot zone in a larger house, unless operating a 3 or 4-way valve.
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Thank you very much to both of you. I was looking to some information about valve chattering in internet and this page was my last option. I didn’t hope I could find information.
It seems like a game. Harold, you are right. One of the clue is wrong; the water flow is 50 l/h. A little mistake. Sorry.
We have the valve installed in a test bench. The valve is bidirectional and the noise begins when the flow is perpendicular to the piston, a 1 bar and 50ºC. The piston is opened between 0 and 0.2mm. The differential pressure is 0.35 bar. If you want to see a section of the valve, I have some plans of the valve.
We don’t know the frecuency of the noise, what would be an interesting fact. To change the resistance of the spring would be the better choice for avoiding a problem with resonance.
Thank you very much.
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Why type of material is you valve closing disc made of?
And what velocity are you using?
If your valve is a soft seat material and in a Globe pattern this may elimate the noise
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The valve closing disc is made of rubber.
Te velocity is 0.25 m/s.
And all the valve is metallic, excepting the closing disc.
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