We have a job that has multiple Mcquay Unit Ventilators. Apparently they keep freezing and busting there hot water coils. This has happened on over 25 units over the past 2 years. A Mcquay factory service technician has hooked up to the board with Service Tool multiple times to reprogram/download new programs into the controller. I am being told that the problem still continues. I guess my company is going to purchase Mcquay Service Tool and send me out to look at this problem. These unit ventilators have outdoor air capability.
I haven't used Service Tool software before. So I am wondering what all can I really do with the software when it comes to these boards? I believe this unit probably has a Microtech II board in it.
Obviously I will check all of the basic sequence of operation checks and look for any possible mechanical issues, but I was wondering if you guys have seen this problem with the Mcquay Unit Ventilators?
If I can do programming changes through Service Tool. What kind of things should I look for to be in this program to prevent this problem? I am assuming if the fan fails, open the hot water valve. If I have a freeze condition, open the hot water valve turn off the fan. Mechanically I will make sure the hot water valves are normally open.
Thanks for any help on this.