Replaced AC Capacitor - Duo-Therm For It Is Blank

[Frank McElroy]

1 hour ago, woodylmiller said:

Having so much fun I decided to open another can of worms.  I found zone 4.  Disconnected all interior data/power cables and verified routing.

T-stat to front A/C(zone 1), then cable goes to middle A/C,(zone 2), then cable goes to zone 4, (the hidden control board), then cable goes to rear A/C(zone 3).  All checked and double checked.  Tested cables, all of them at least 4 times with cable tester, all good, no shorts.  Previous thoughts about a short was actually the zone 4 being connected and my tester must have responded to that load as a short.

Checked, double checked, all the danglers.  No apparent damage.  So connected all couplings and RJ plugs to their jacks.  Plugged T-stat back in and attempted reboot.  Never got the FF reading.  The backlight is on, and zone 1 is showing, but none of the other zones.  More rebooting and still the same result.  Unable to reboot the T-stat.  I next turned on the 120vac to all three units.  Middle and rear A/C came on.  Yet zone 2 and zone 3 do not appear on the T-stat.  Nothing but zone 1 appears in the T-stat display, without doing any control of the zone 1.

So this is what I have now.  With the T-stat disconnected from the wall, no cable attached.  A/C zone 2 comes on.  A/C zone 3 comes on as soon as I turn the 120vac power on.  Zone 1, nothing.  The A/C are coming on immediately, like not going through the EMS were there would normally be a delay before start up.  I then disconnected all interior cables and at that point none of the A/C come on.

I did not mess with any settings on the control boards, never touched the dip switches.  The T-stat comes on to zone 1 as soon as I plug it in, but no control of the zone 1 A/C.  I can control zone 1 when isolating that unit by connecting only the T-stat to unit one with no other dangler connected, same as plugging straight into the control board from the roof location.  The A/C responds as it should going through the EMS with the delay start up.  With only zone 1 and T-stat connected the stat will reboot and give me the FF.  But still no zone 2,3 or 4 showing.

Not sure where to go to next.  Only thing I can think of now is getting the T-stat to reboot.  One other thing about the T-stat, as soon as I plug it in the light comes on and displays zone 1 even with the switch on the bottom in the "off" position.

Just when I think I'm finished, it pulls me back in.  LOL

Woody Miller

09 Dynasty

You MUST reboot the thermostat with 120 VAC power turned ON to ALL air conditioning units.

[woodylmiller]

Thank you Frank.  Here is the problem; as soon as I turn AC power on both zone 2 and 3 come on and the stat does nothing except show zone 1 which is not running.

Next problem is I can talk to and operate all 3 zones while isolated and power input is directly on the red and black P6 danglers from the inside via a jumper from the 12vdc buss.  This works while plugged into the RJ jacks on the roof.  All data/power buss connections open on the inside.  So each unit is totally independent from the others as well all danglers and couplings disconnected.  I then plug the 2 danglers in the jacks on the control board and go inside the coach.  From inside I then attempt the same functions with the stat plugged into either of the 2 danglers.  This is where things go wrong.  I can control zone 1 while all other zones/cables are disconnected.  Same as on the roof.  Then I go to zone 2 danglers and I get nothing.  The stat is dark, won't reboot, and blank screen even with the AC power on.  So nothing at all on zone 2.  Zone 3 is the same thing; no control once hooked up to the danglers.

My logic tells me the units are good.  Pretty sure the stat is OK since I have no problems with it on the roof doing the isolation process.  So tomorrow I plan to buy 100 feet of 4 conductor flat cable and replace all danglers.  Sadly there is not enough existing dangler cables to try and use them.  I can barely get one of the danglers to the board jack on one of the units.  Zone 4 danglers were cut off flush with the box except for the two blue wires which are connected.

Talking with Tom a possible board switch to see if it's a bad board.  If I leave the AC power on while the units are isolated nothing happens, but connect the data/power cables and zone 2 and 3 fire up and zone 1 does not and will not respond to any input from the stat.  Fortunately there is enough interior data/power cables to put on new plugs.  So that's my next plan of attack, replace all the data/power danglers. 

I used the wrong terminology earlier about the EMS.  Had that confused with the A/C or Dryer system.  But there should be a delay between a stat call for cooling and the actual start of the unit.  That does happen while up on the roof during the isolation testing.  There is no delay start on 2 and 3 when everything is connected and 120vac is turned on.  That has me scratching my head.  I believe that delay is to protect the compressor and to prevent a hard start.  That process should be built in and independent from any other cause or situation.

Woody Miller

09 Dynasty