I just started Seti@HOME and I'm trying to get my first work unit. Even when I manually update it just keeps deferring the communication to a few minutes later. Is there anything I need to do to in order to receive work units?

Have patience.
Earlier there were all kinds of database problems. The project's been taken down twice already today, perhaps there'll be more times this happens.

The end result is that there are lots of hungry machines out there, which when they all ask work at the same time suck the Ready to send buffer (visible on the server status page dry. Your system just has to be asking for work at the right time to get some.

Else you'll just get:
19/09/2015 00:05:41 | SETI@home | Project has no tasks available

There's no need to press Update either, as that'll just make things worse.
So, if you only want to run Seti, you need patience.
If you want to run any work, there are plenty of other projects available that would love attention.

Edit: It's also possible that the project has temporarily shut down the feeder (despite the status page showing it's online), to give the RTS buffer a chance to grow.

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