solenoid valve on HGB

[Kirky]

Hi all hope you are all well and rested after the Christmas break. Got a problem with a solenoid valve on a Hot gas bypass. As I'm sure you have guessed it a Airedale chiller unit working as part of a close control system. When I was first called out to the unit I found that the pipe had split on the bypass due to vibration and work hardening . So I replaced the bypass pipework and solenoid valve as it was a simple liquid line solenoid valve which was installed I replaced like for like. Against my better judgement but that's what the powers that be wanted. Anyway the valve lasted 2 months and rupture. Clearly not fit for purpose. Spoke to Airedale and traced correct valve have installed the valve and it's working however making a load buzzing sound when operating just doesn't sound right. I have kept the bypass as short as possible and installed it in such a way that when the valve closes gravity allows the oil to drain back is there any other factors I haven't considered which could cause this buzzing sound when the coil energises. Haven't really worked on many HGB with solenoid valve in the past only seen them on Airedales and don't look after many of them any advise welcome

[stufus]

Hey Kirky
Is it the coil that's buzzing or is it vibration in the valve itself.
Obvious question , is the coil voltage correct?
What type of valve is it(brand/model)
Cheers
Stu

[Kirky]

Hi Stu

It's a Bailey Gill GF1-4F 1/4 inch flared valve the coil voltage is correct 230-240v. It the valve that is vibrating almost seems like the coil isn't powerful enough to properly open the valve . Everything is working ok just very noisey worried the valve will fail again what you think could it be that I don't have a big enough differential for the valve to operate properly suction pressure on the system seems low at 4 bar for 407c discharge pressure 17 bar

[stufus]

Not a fan of standard solenoid valves for HGB as the internal diaphragms just aren't up to the job and struggle at the higher temperature (not pressures).
Is it being used for compressor loading or evap freeze protection?
At what back pressure is the valve being energised ,what's the application CCU?
Have you gone through the controller parameters.
Better off with a straight forward mechanical pressure regulator.
Cheers
Stu

[chemi-cool]

Stu, its the same pressure as on the liquid line, its the higher temp and vibrations from the compressor that f****s it up.

[stufus]

Well spotted Chemi
Should say higher temperatures.
Cheers
Stu

Stu, its the same pressure as on the liquid line, its the higher temp and vibrations from the compressor that f****s it up.

[Kirky]

The application is CCU and the HGB is for compressor loading I'm not a fan of solenoid valves on HGB myself but for some reason Airedale are. I have used the valve specified by Airedale so must be a pressure issue when I first installed the new valve and ran it up it's was fine hissing away nicely but since we hit setpoint and the unit doesn't have much load started buzzing. Im going back to it Monday so will check pressures on and off the valve at the mo only have suction pressure at 4 bar rising to 5 bar when valve opens and discharge 17 bar dropping to 16 when valve opens. Chiller controls very simple can specify water temp setpoint which at the mo is 8 degC which the chiller is pissing at this time of year.

[Kirky]

Hi all update

Been back to site today and valve has ruptured. Checked pressure on valve 17 bar and off 5 bar differential of 174 psi don't know if this is enough to operate the valve properly can't find any data sheets on bailey Gill valve. Tried getting in contact with manufacturer no reply yet. Vibration seems to subside when load on chiller increases. Finding this most puzzling valve seems to operate chiller works fine it's just this buzzing and then valve ruptures either on stem or on flare due to vibration .

[stufus]

!Bg)ttOQ!mk~$(KGrHqIH-CYEsLCt-zpkBLGos+fJw!~~_3.JPGYou could try putting 1/4 vibration eliminators either side of the valve if you're going to replace it again like for like again to deal with the vibration issue.
But the high temps will still be a factor.
Personally I'd do away with it all together and fit a mechanical discharge bypass valve if it's for compressor loading,something along the lines of a Sporlan ADRSE-2(above pic) and depending on compressor type,a crankcase protector(pressure limiter).
Failing that get Airdale involved (if they will)
Cheers
Stu

[Kirky]

Cheers stu my company have decided to send a senior engineer to look at the job which is fine takes pressure off me. I'm going to stick with him see what he does that I didn't. Thanks for advise though will update soon

[stufus]

No worries mate ,keep us posted.
Cheers
Stu

Cheers stu my company have decided to send a senior engineer to look at the job which is fine takes pressure off me. I'm going to stick with him see what he does that I didn't. Thanks for advise though will update soon

[Kirky]

Hi Stu

Right senior engineer thinks that the solenoid valve is failing because it is operating / clickling on and off to much so he wants me to widen the dead band so the valve will not operate as much. Don't suppose you are familiar with Airedales and CAL3200 controllers and can guide me towards how to widen the hot gas dead band

[stufus]

Hi Kirky
The CAL 3200 is I think a generic controller used by Airedale .You Will probably need to cantact them for guidance as I'm not familiar with the I/O's (inputs-outputs)they use on the controller to perform the HGB.
The last time I saw a Cal controller it was on a spray painting booth.
I found this but it doesn't really clear anything up for me.
http://www.instrumart.com/assets/108/Cal3200Manual.pdf
Maybe one of the other members is more familiar with them.
Or your senior engineer could attend and guide you through the process ,since it's his judgement call.
Sorry mate
Cheers
Stu