My WorkCentre 7328 is setup to go in low-power mode after five minutes and in sleep mode after ten minutes. If I recall correctly, at my previous office building location (with different router/network) the units fan did not run periodically in sleep mode.
Now, the unit appears to be in sleep mode, the Energy Saver light on the panel is illuminated, but I hear a periodic relay clicking and a fan turning on/off periodically.
Every now and then the fan is completely off, but doesn't happen often.
I am on a router that supplies wi-fi to other office tenants and there may be others also connect through CAT5e. But, I am the only one that uses the printer.
Why does the fan keep coming on periodically, but appears to remain in sleep mode?
Because heat still exists internally. The new office has probably got less airflow near the printer, so the fan kicks on more often, or you are simply located in a better position to notice it.
If you think the network plays any part, simply unplug it from the LAN when not in use and verify if the fan stops coming on.
That all makes sense. I unplugged the LAN and found the fan turned off after about five minutes. It did not turn back on for the hour I waited. I then plugged the LAN back in and the fan immediately came on and started its cycle again, which is to stay on for about 15-20 minutes turn off for 30 seconds and then turn back on again. I should say that the unit was in power saving mode this entire time.
Could my router be sending something to make the fan wake up like this? Or perhaps one of the other tenants unknowingly has a computer connected sending something causing it to doing so?
Then you are in a bit of a bind, I have only ever come across one case of a printer fan coming on because of a network, and it was on this forum, and the user ended up discovering there was a program running on a PC that caused it, and the worst part is that the program was DIVX/DVD burning software that in no way dealt with printing, and in your case it would seem it isn't your PC anyway.
You could use IP filtering to just block everyone but you from having access to the printer, but if your IP address ever changes you will lose access, and without access, you cannot undo the change. So you can only do it if you use a Static IP on the PC you use.
I can't explain all the details, but here is an example, if your PC was using 192.168.1.100 and you did exactly this filter, you would be the only person who could access it on the LAN. So no other PC could cause issues at all.