Carrier 30gxn.... Anyone seen this?

[northwestmechanic]

I have two alarms going off and shutting the chiller down, t999 and t998 both are for "loss of refrigerant flow" one in circuit a and one in circuit b. According to the history it just started happening the other day, the liquid line filters are good ,suction valves are open and I am getting real good flow for the chilled water. Each circuit runs for approx. 3 mins and then they trip off with this alarm. Both EXVs are frosted up after they trip off.

Has anyone seen this before, I find it strange both circuits are acting up at the same time... Telling me it's some thing that affects both ie: chilled water etc

Any help is much appreciated

Thanks

[nyrb]

Although I have never experienced that scenario I would be investigating my liquid line solenoid valves and EXV operation to start. You may have an issue with your EXV driver board.

[Dallas Duster]

Yep I'd start ohming out the exv motors. What series is it? How low did your suction pressure go?

[northwestmechanic]

I am unsure on the series, the suction pressure was dropping right into a vacuum on circuit B and circuit A was running normal pressures for about 3-4 mins then it dropped into a vacuum as well. i will have to ohm out the exv, but when the chiller starts up and goes through its pre start up both EXVs move fully open and fully close

Thanks

[Dallas Duster]

I am unsure on the series, the suction pressure was dropping right into a vacuum on circuit B and circuit A was running normal pressures for about 3-4 mins then it dropped into a vacuum as well. i will have to ohm out the exv, but when the chiller starts up and goes through its pre start up both EXVs move fully open and fully close

Thanks

So there is a sight glass on the exv?

[northwestmechanic]

yes

[Dallas Duster]

yes

Oh boy I will pm you later

[northwestmechanic]

ok..... that doesn't sound good

[Dallas Duster]

ok..... that doesn't sound good

It is bad I just realized you are not a pro member and I cannot PM you . Shoot me you email address mine is in my profile.

[nique]

why keep it a secret dallas lets have your thoughts. I've seen this many times, low charge, bad exv, bad transducer, loss of program, or in this case I would think since it started happening to both circuits at the same time I would think that the board went bad or the program needs fixn. It seems that with those exv's there was a upgrade in the programing because the number of steps was wrong from the factory.

[b-man]

Dallas Duster
Could I get any info on this fault also? We just started on an account that has had this problem. I am just getting into troubleshooting and thought I would search for any posts about this fault.
Thanks
b-man

[Dallas Duster]

Dallas Duster
Could I get any info on this fault also? We just started on an account that has had this problem. I am just getting into troubleshooting and thought I would search for any posts about this fault.
Thanks
b-man

Basically all I gave him is my experience with the chillers nothing that gave the farm away. If you ask me specific questions about problems I can probably help you out better that way.