calling all danfoss AKV experts

[littleyapper]

hi all your very valued opinions please:
the factory super heat settings on danfoss electronic valves are between min 3 max 12
1.should these be adjusted or not!!
2.i am led to believe that the controller will/should find its best possible superheat any way
3.doctors differ patients die
all your thoughts welcome!!

[Grizzly]

Hi Little Yapper.

You are correct you would not normally adjust these settings. I am finding it difficult to think of a situation where you would need to operate outside of these?
You are also correct that the Adapkool Controller floats the s/ heat setting based upon the operating conditions at any given time.

Finally I went to a doctor once about my S/Heat. He advised More Beer.
Grizzly

[Mark]

hi all your very valued opinions please:
the factory super heat settings on danfoss electronic valves are between min 3 max 12
1.should these be adjusted or not!!
2.i am led to believe that the controller will/should find its best possible superheat any way
3.doctors differ patients die
all your thoughts welcome!!

Hi littleyaper,

How is the AKV controlled, what application is it used on, multiple units / plant.......etc

Mark

[Magoo]

Hi Little yapper
If you are running the adapkool software on a computer monitor, you can set superheats on each evaporator. using service access setup.

[RANGER1]

littleyapper,
Which controller are you using & what would the application be?

[littleyapper]

ekc 414a on this job but its a general question ..its a super market diff cabinets chill + frozen
i am 100% behind grizzly and have operated this way for years.....but i am getting different views now from different people.
i understand that you can set up super heats etc (with or with out a computer )but WHY would you need to if the controller is as good as they are saying.i am a big fan of danfoss and their electronic valves just a little confused at the moment!! If you are to narrow the band from 3 to 12 down to (for example)4 to 8 why use these elect valves at all use a t.e.v with a lovely super heat of 6(mmmmmm)
i thank you all for your input and if i knew where the scales were gone to thank you i would...
Mark they are controlled with s2 s3 s4 s5 and suction transducer using 50% air on and 50% air off as temp control ... site is working well and has been for years but my s/heats are all up aroung the 10ish area but are moving up and down....DISCUSS
THANKS AGAIN ALL .... I HAVE SAID IT BEFORE AND WILL SAY IT AGAIN HIS SITE IS THE DOGS BOLLIXS (thats good where i come from)

[RANGER1]

littleyapper,
The only basic things I can suggest to check would be full liquid line at AKV with a bit of subcooling
as well as head pressure control.
They s/heat tend to follow head pressure a bit if its not very stable.

[Grizzly]

Partial blockage somewhere maybe?
Liquid line filters OK? Sub-cooling OK?
(Read system charge issues?)
Appreciate your comments LY.
Have you previously monitored your S/Heats as closely?
Or is it as you suggest if the control is as finite as Danfoss suggest, why 10k?

I understand your need to clarify what is going on. I would think most on the forum are similar. It's the sign of a good Engineer if you ask me.

Good Luck with your quest.
Grizzly

[littleyapper]

thanks again all ....how about this !!!
on start up of a new plant would you leave the factory set superheats (again on electronic)or would you narrow the band i will finish this thread now as it might be getting painfull
cheers

[Silhouette]

Is the controller set for on/off control or modulating control?
If it's on/off then the AKV shuts completely on reaching control temperature this can produce a low then wide TD, on modulating control the controller will reduce the AKV opening time as it nears control temperature then modulate the AKV to maintain control temperature this can produce a constantly wide TD!

[Eeram]

Hi Littleyapper,

I am working on about 80 Danfoss Adap kool systems, running between 3 and 8 superheat. From Citrus refrigeration, fish freezing, supermarkets and ice cream factories. If the AKV valve selection is spot on and the plant suction set point is set correctly and the capacity is there, you should be able to maintain a suprheat of 5. No need of a computer to set superheat. You can do it with a push button display, connected to your controller.

[Peter_1]

What's then the advantage of the AKV against a TEV if the TEV can run with a Sh of 4 K and a low DP over the valve?

[simon@parker]

if u have had this site up and running for a long while have you got a site energy consumption monitor ? if ya have could u not reduce yr super heats and see if this reduces energy use ? just an idea if it does and the plant is ok its a win if it doesnt and everything still ok we all learn somat and u get the glory lol

[750 Valve]

I ALWAYS narrow the band, what good is 12K???!!!! I have seen them pulldown after defrost and sit around the 12 mark for an hour or two. I always set AKC164 to something sensible, like 4 low and 7 high. AKC550 and EKC controllers using a transducer and not a coil in temp keep a lot tighter control on the superheat and I have commissioned cascade co2 installations where we have them controlling R134a/Co2 heat exchangers at 3K low and 4K high, been operating efficiently and smoothly for 5 to 6 years now.

[Y L Lai]

3 to 9 for my case. it depends on the coil. some coil have high mss, so at 3 or 4, massive liquid floodback.