Trane Intellipak question

[hvt]

Hello all, despite 21 years as an hvac technician I have yet to work on an intellipak unit, I have seen plenty of whatever they were called pre - intellipak, and Voyager units as well.
My question is about variabe speed drives in the intellipak 1 units,
I understand that they are installed in the outside air plenum, are they in a weather proof enclosure?

The units I have in mind are 105 ton models, they have two 40 horse supply fan motors and one 30 horse power exhaust fan, they have IGVs and discharge dampers to modulate air flow, I am looking into feasibility of installing VSDs

so far it looks like it will fwickin expensive!

[BKLYNBORN]

Pre intellipak units were just called RTU's the clear language display or the UCP-2 controller made it intelligent according to Trane. As far as your statement that it is a lot of money to install drives on these units what did you expect everything is expensive just look at the price of refrigerant. I would not put good money into something that old because the owner should be thinking about replaceing the units instead of updateing them. Because they come with the drives allready inside the units in the back section not outside in an inclosure or live with what they have and rebuild the IGV'S thier is nothing wrong with they operate it's just that everbody is drive crazy today.

[Phisher]

I agree with BKLYNBORN it's not worth the money for something that old. The drives that come installed in the new Intellipaks are mounted in the oustside air plenum. The drives aren't mounted in a weather proof encloser because they need air flow to dissipate the heat.

[jayguy]

they are NOT mounted in the outside air plenum.

they ARE mounted in the outside air AREA and are sealed from the outside air. there are ventilation slots that expose the vfd cabinet to the return air for heat dissipation.

i would agree to the idea of not installing vfd's. not because of the age of the unit, but becuase the only advantage of removing IGV's and installing drives is the extra diagnostic ability (a rare need in these units) and 'soft start' use. other than that, there is an extremely long payback in most cases (probably on the order of decades).

good luck.

[allstar08]

Depending on where you are and what your electric rates are drives can pay off much faster then you think. How the unit is set up for static pressure will also make a difference. With the addition of local utility rebates, I have been a part of projects that have a 3 year ROI.

[jayguy]

attached is a diagram from trane on the power inputs versus type of fan modulation.

IF...you have inlet guide vanes already installed, there isn't much savings by going to a drive.

IF...you have constant volume, then yes, you could go to a drive, however, you still have to convert the system over to a vav type system and controls.