Ultrasonic Humidifiers Experience

Wouldn't you want a de-humidifier for a telecommunication room?

Check

Ultrasonic humidifiers are a maintenance nightmare.

Agree with willard3.

Xera, for info -- telecom and server rooms don't have much latent load at all, but tons of sensible load. They don't require much outdoor air, either, so even in summer the humidities can get extremely low.

Direct steam injection types are time-tested. Still some maintenance to do, but it's simpler.

My experience and opinions only.

Good on ya,

Goober Dave

Static electricity. I forgot.

Infrared would be the likely easiest installed option, but don't save the energy. These are most commonly specified in CRAC units for convenience and use of integrated humidity/dewpoint control.

Electrode steam generating drums are a good option and some of these systems self-manage mineral deposits. Such systems need a tempered drain for dumping hot water in purge.

The problem with ultrasonic is that the are direct contact and installed in the enclosed airstream. As you evaporate, you concentrate minerals and they clog up with deposits and need a shutdown to access. With adequate redundancy, the access is not usually a problem, but if installed in a ducted system can be a real pain. A high purity water source is required.

As KIWI said,
and you may miss his point in his last sentence, "a high purity water source is required". Meaning you need RO (Reverse Osmosis) water system installed (Money upfront).
stagnant water in Ultra-sonic reservoirs could be a problem, you will need auto drain every 20 minutes or whatever.
RO water and Ultra-sonic humidification is good if you have substantial humidification. If you're in the 30 to 50 KW range, you may want to stick with infra-red as suggested by Kiwi.

Also check your Telecomm manufacturer litterature and equipment warranties, most equipment nowadays work in very harsh environment. You may need only boosting say from 10% to 30% humididity, no need to go to the 50% RH business.