Carrier multi zone rtu

[joeywrists]

Hey guys I'm working on a carrier multi zone rtu it's a 50me-040---520bc replaced the compressor on Friday tried to start it today and had no luck is there anyone on here that's had experience with these units been in the trade for almost ten years but I've never seen a unit like this before thanks for any help

[dlove]

is there a call for cooling from the stat? did you check the control side voltage

[timebuilder]

I had a similar unit the other day. I found a defective remote smoke detectot head.

[joeywrists]

Yes there a call from cooling on all 8 stats control voltage on the stat side is 25-28 volts I have 115-120v off my secondary transformer and 460-490v at my line voltage terminal block everything seems to be responding except I'm not getting power to the timer control board that brings the first compressor on and I don't think it's a smoke alarm indoor fan is still running

[dlove]

Yes there a call from cooling on all 8 stats control voltage on the stat side is 25-28 volts I have 115-120v off my secondary transformer and 460-490v at my line voltage terminal block everything seems to be responding except I'm not getting power to the timer control board that brings the first compressor on and I don't think it's a smoke alarm indoor fan is still running

Economizer locking you out? safeties, low voltage fuse. compressor contactor coil bad. if something blew the compressor you may have other electrical issues...Timer board fried?

[joeywrists]

Not the Econ checked all the fuses and safety's don't think the timer board is fried just not getting voltage to it and from what I can tell its supposed to get it from this relay board that's got 4 relays on it but I think only one is for cooling and comp contactor is new