"knocking" Apirlaire 560 - need an arrestor?

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  #1  
Old 01-02-19, 11:22 AM
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"knocking" Apirlaire 560 - need an arrestor?

My Aprilaire has always produced a loud knocking sound when the the solenoid valve is shutting off.
Recently it has been bothering me more. Is an arrestor the fix?

It seems that Aprilaire even offers an arrestor
https://www.airqualityparts.com/apri...-arrestor.html

I am assuming this model would work as well?
https://www.amazon.com/86592-Shock-B...MHHFQG03ZHY77R
 
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  #2  
Old 01-02-19, 01:25 PM
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Should help. You must have very high water pressure causing water hammer.
 
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Old 01-02-19, 04:45 PM
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thanks. i don't think I have particular high water pressure. I also have the supply valve only slightly open in order not to waste water in the humidifier.
I don't have the issue with other devices such as ice maker, washer. I think the the solenoid installation on the humidifier attached to the large metal duct amplifies the issue.
 
  #4  
Old 01-02-19, 05:11 PM
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I also have the supply valve only slightly open in order not to waste water in the humidifier.
That's a good reason for knocking. The valve requires water pressure to close.
I have never in 25 years seen that problem.

If you want to mess with the water flow..... change the orifice on the output side of the solenoid.
 
  #5  
Old 01-03-19, 03:37 PM
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Originally Posted by PJmax View Post
That's a good reason for knocking. The valve requires water pressure to close.
I have never in 25 years seen that problem.

If you want to mess with the water flow..... change the orifice on the output side of the solenoid.
I turned the water full open to test. Getting the same bang.
 
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Old 01-03-19, 05:33 PM
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I would recommend getting an inexpensive gauge to check the house pressure.
Pressure test gauge
 
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Old 01-05-19, 09:18 AM
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I got a pressure gauge. I measure between 76 and not quite up to 80 psi.
 
  #8  
Old 01-05-19, 09:53 AM
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I would consider that not only high for the humidifier but for the whole house. Normally the incoming water pressure is kept at or below 55 psi. You may need to consider a whole house PRV (pressure regulating valve).

I had never had a problem with one of those solenoids chattering. I went thru all the Aprilaire specs and could not find a maximum recommended water pressure on the bypass type units. If you aren't going to address the whole house pressure you may need to change the solenoid.
 
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Old 01-05-19, 01:57 PM
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I checked and I don't have a regulator. Would need to get one installed.

I still find it interesting that Aprilaire actually offers an arrestor:
https://www.airqualityparts.com/apri...-arrestor.html
 
  #10  
Old 01-12-19, 09:58 AM
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Here is an update.

I ended up ordering a water arrestor as a short term fix:
https://www.supplyhouse.com/sh/contr...ct_id=660-GTR0

During the installation I noticed two things:
1.) My solenoid did not have a strainer installed on the supply side (little black part). I obtained one. Took me a while to figure out how to get the part inside. Needs to fit into a slot, so the part needs to be turned and pushed.
2.) I believe I had the wrong orifice installed. I found a white part. Based on Aprilaire's instructions, the white one is for a different model, the 560 needs a yellow one. So, I switched to yellow part as well. I think it helps reducing the water flow. So, I don't have to play with the supply valve anymore. But I don't know the water flow of white part. I foudn data on yellow part: 3 GPH. Does anyone know flow rate of white part?

As a result, the humidifier switches on/off whisper quiet. I should have done this a long time ago :-). I still will need to watch the overall water pressure situation...
 
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