Long term airflow issue.

This is a CEM Classic. (The Original Sensor Dimmer Controller).

See the vents on the right hand side of the CEM?  Power down the rack and pull the control module out and look directly down over where those vents are. There should be a Silver piece of metal that obstructs your view of the circuit board, or a secondary PC board raised off of the main board. If neither of these exist, call technical service and ask about something called a snorkel.

While you have the controller out, blow it out with compressed air.

When the rack is on, is the rack fan running and exhausting air when dimmers are on? If you have another sensor rack to compare it to, is the air pressure coming out of the top of the rack about the same between racks? (This will tell you if the fan is good).

Thanks for all the tips. Yes the CEM Classic does have a "snorkel" and the fan is blowing at a brisk pace. I was not able to compare it to other racks since i am a small one rack installation. 

I powered down and blew out the vent and air flow sensor area and have powered back on. 

Ran a load for about 30 min this morning and have had the house lights (LEDS) running all day, about seven hours now. So far the error has not returned so for now I am good to go!

Thanks

-R

Randall,

Could you please tell us what version software you are running?  Press [Reset] and when it reboots it will give you a version number of probably 3.10 or 3.11.

Ok, so I am guessing you have one of these versions [or earlier] as some of them had a short timeout for fan sensing.  Here's what I mean...  You start with the fan off, you bring up lights and the fan turns on.  During the time the fan spools up, the airflow sensor may determine [too early] that there is not enough airflow.  If so, it is possible that your lights will go for a couple of seconds and then back on again.  This only happens when the fan is first turned on but since the error message is "sticky," you see it there all the time.

So in addition to getting the sw version, do this little test:

Turn off all your lights.  Wait 15 [or more] minutes for the fan to spool down.  Clear the error at the CEM by hitting [Clear] when the error is displayed.  Go back out into the house and turn on lights.  If they come on, go off, and then come back on, we've found the issue.

Let me know,

David

Randall,

Could you please tell us what version software you are running?  Press [Reset] and when it reboots it will give you a version number of probably 3.10 or 3.11.

Ok, so I am guessing you have one of these versions [or earlier] as some of them had a short timeout for fan sensing.  Here's what I mean...  You start with the fan off, you bring up lights and the fan turns on.  During the time the fan spools up, the airflow sensor may determine [too early] that there is not enough airflow.  If so, it is possible that your lights will go for a couple of seconds and then back on again.  This only happens when the fan is first turned on but since the error message is "sticky," you see it there all the time.

So in addition to getting the sw version, do this little test:

Turn off all your lights.  Wait 15 [or more] minutes for the fan to spool down.  Clear the error at the CEM by hitting [Clear] when the error is displayed.  Go back out into the house and turn on lights.  If they come on, go off, and then come back on, we've found the issue.

Let me know,

David

The airflow error has not yet returned since I power cycled the rack and blew out the sensor. 

I am running v3.0 so maybe a software update would be in order, anyone want to save me some time and send a link for info on upgrading the CEM classic?

Thanks!

Upgrading of classic CEM modules requires chips to be replaced. These can be purchased, but honestly, if 3.0 is working for the customer, there is little advantage to upgrading unless it is to fix a problem.