My understanding is its powered open / closed. no power it sits.

https://youtu.be/XHtRHiKIsEU

 

Yes that's becoming my thoughts . hard to test , i know the board should be calling , 5v dc tells me the eev should be open , resistance of eev is good , But if the ac that drives the eev is intermittent ,as in a pulse adjust eev , remove signal eev then sits waiting for next pulse open or close . If the eev is damaged and does not move , u have to catch that 1st pulse , whilst doing other things with creating the call etc . I am leaning now more an eev fault .
Checked a lot of resources but can not find that level of detail . Will try heat craft on Monday.

 

I have seen failures of the 4-pin cable to the EEV, maybe due to poor connection/ corrosion. Heatcraft says to ohm out the motor (coil) of the EEV. Should be 150 ohms A to B, and from C to D.

But, if the cable is bad, it won't work. Often the cable just isn't making a good connection to the valve motor. So, my advice is to leave the cable attached to the EEV, then unplug the cable from the board, and ohm it out there. That is how we discovered one not working. Ohmed at properly at the valve itself but ohmed out bad from the board end of the cable.

Also be aware, it is possible to force the cable into the EEV at the wrong angle and this will result in valve not working. There is one pin that is ever-so-slightly bigger, and that must be oriented correctly.


https://www.heatcraftrpd.com/PDF/I&O/H-IM-QRC.pdf

See page 17


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In response to your question about voltage. The valve receives 20-22vac only when it is moving opened or closed. It does not continuously receive voltage.

The 5vdc does not go to the EEV. Rather, it is just a modulating continous voltage being output by the board 0-5VDC at the EXV test pins. So if you read the parameter ESV (number of steps that valve has been opened from 0-255), it should coordinate with the voltage you read at the board. 0 steps should be 0VDC, 128 steps should be 2.5VDC, 255 steps 5vdc. If the ESV was showing 200 steps but the EXV pins show 0vdc, then that would indicate a failure in the board.

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Tripp is right.. its pretty much a stepper motor.

It only receives power when the valve is being commanded open or closed. Without power it will simply stay right where it is until power is applied to it

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And... to further prove his point..

Carefully check that harness going from the board to the valve.

I had a harness that rubbed up on piping behind the board and you couldnt see it.
The driver in the board kept going bad, valve was fine.
The wiring harness was shorting out to the piping so when the board sent a command, the driver in the board would short and ruin the board.

Carefully check the harness. Repair or replace the harness if needed [emoji106][emoji106]

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I have this same problem. One freezer with 2 systems. One valve wont open with the 5 v dc and then the other system wont pump down with 0 v dc. Checked resistance and wiring harness.

I prefer a solenoid for pump down, Txv and 1609-101.

 

A big potential issue as Trippin stated is to make sure the cable to the EEV coil is correct , it can be easily placed the wrong way on the head , there is only 1 correct way , check out Carel web site . United sells a Carel stepper motor test magnet , $33. very reasonable , You can rotate the magnet on the head and feel the the resistance change as the eev opens and closes . Pumpdown the system with a board commend , then u can use the magnet to confirm eev is actually closed ,

 

Sow we have the SQ kit that allows us to repair / replace a large variety of X-Valves in the field. What do we do when there's an issue with an EEV?

 

Size a Sporlan TXV, LLS. Put a thermostat and time clock on it.