Carel evd

[nando]

Hello,

I have a Carel EVD expansion valva electronic.
I have a low pressure and a high pressure probe, and suction and liquid sensor ntc.
I have all the time a wrong value with the high pressure probe. The others are ok.
The high pressure probe is parallel on the low pressure, and S3.
The probe is correct. Try with another is the same.
Carel dont answer me.
Anybody an idea?

[narkom]

15061
Is your connection like that? Are the S1 and S3 probes of the same type? What is the probe output voltage?
15062

[nando]

S1 and S3 are the same type: ratiometric

[Brian_UK]

Is the controller set to match the sensor?

[nando]

Yes.
The supplier has a lab box with the valve and sensors. He has the same problem.
Changing the parameters sensor active or not doesnt help

[Brian_UK]

Okay, so if the components and cabling are correct then we need to look at the mechanics.

How does the sensor reading compare with actual pressure?

Is the sensor connection to the pipework good? By this I mean is the valve pin depressed properly by the sensor when it is screwed on. Test it by fitting a tee-piece to the access port and fit your sensor to test both items.

[narkom]

Can you measure the probe DC output voltage between S3 and Gnd?

[nando]

Okay, so if the components and cabling are correct then we need to look at the mechanics.

How does the sensor reading compare with actual pressure?

Is the sensor connection to the pipework good? By this I mean is the valve pin depressed properly by the sensor when it is screwed on. Test it by fitting a tee-piece to the access port and fit your sensor to test both items.


Yes. The sensor is correct. It measure 33 bar, we have R404A. The real pressure is 17 bar.
It is strange that on the lab box we have the same problem. The lab box is from Carel.
The valve works very good. I only want the high pressure for reading only.

[nando]

I will do that this evening (belgium time) if i am back in time (4 calls already and the day just begins).
Or i do this after x mas.
Thanks for helping

[nando]

Can you measure the probe DC output voltage between S3 and Gnd?

I will do that this evening (belgium time) if i am back in time (4 calls already and the day just begins).
Or i do this after x mas.
Thanks for helping

[Brian_UK]

Is the correct scale range for the sensor selected and set on the controller?

Sorry, second question - what are the ranges of the high and low pressure sensors?

[nando]

The supplier gave me this: low pressure 4-20ma -0,5 / 7 bar high pr 4-20ma 0 / 30 bar.
In the configuration if i want to change S3 it always go back to “not used”.
I measure 8,5 V between GND and S3 display shows 33,7 bar. Real i have 17 bar.
measure: S1. 2,45 V 3,5 bar display
S2. 2,45 V 6’C display
S4. 1,65 V 22’C display
Maybe i have to use 0-5 V?
The supplier gave me for another installation for low pressure 0-5 V and high pressure 4-20 mA!
I guess it have to be two of the same sorts, not?
And wich one, V or mA?

Probe 4 is in programmation also “not used” and impossable to change.
And this probe measure good.

Thanks
Happy holidays!

[Brian_UK]

So you do NOT have ratiomatic sensors, they are 4-20ma sensors.

Yes, you must use two of the same sensor type.

Set the controller accordingly.

[nando]

The both sensors are 4-20mA.
What is ratiometric? Is this the 0-5V?

[Brian_UK]

Yes, see your parameter list that you posted earlier in post #2

[nando]

Yes, see your parameter list that you posted earlier in post #2

I will change the probes next week with 2 0-5V probes.
Lets see if this is better.

[nando]

Hello
Both changed to 0-5V. Now it is ok.
Thanks a lot.
Happy new year.

[Brian_UK]

Good news, thank you for letting us know.