Installed in Oct 2010 - 25HPA536H0031010 Heatpump, 58CVA090 Furnace, CNPHP422 Coil, SYSTXCCUID01-B Thermostat.

Have had recurring problems with communication faults. After many return visits by techs from the installing company, no solution has been found. They replaced the controller boards in both furnace and heat pump and the UI. Problem still persists.

It is in failure mode now. 40 events outdoor unit, 33 events indoor unit - communication fault.

I changed the mode from hybrid to furnace only hoping to eliminate one variable but I think the outdoor unit is still being polled for OAT. Maybe I should disconnect the ABCD bus to the outdoor unit?

Any thoughts on how to diagnose this problem? If this follows typical behavior, this will clear in a few hours.

Thanks.

 

Unfortunately, it appears that you are experiencing the hazards of buying the latest and greatest technology. Sometimes it doesn't work or doesn't work very well. Existing repairman lack the experience to be able to diagnose and repair the problems, and manufacturers probably haven't figured out the problems either.

Government, however, is enthusiastic about the latest and greatest and often subsidizes and encourages the purchase of the latest and greatest.

I don't have the experience to diagnose the problems you have either. I would suppose that Carrier will figure out the problems eventually and fix them under their guarantee. If your installer can't figure it out, they should be in contact with Carrier technical representatives, keeping them informed of the issues until Carrier solves the problem.

 

Could be that new wiring is needed between the units and the stat. Or there is a option to change the unit from communicating to standard wiring with the use of a relay board I believe. Check with your installer.

Another problem could be if you have power issues at your home.

Best thing for you to do is contact Carrier directly and tell them to have the issue solved or you will be contacting an attorney.

 

A tech found a splice that may not have been solid and also a loose ground wire on the flame sensor.
Since it is such an intermittent problem, it will be a while before I feel I have a fix. The tech spent 2-3 hours checking everything and charged it to the expired warranty since it was a persistent problem started under warranty.

Carrier referred me to a factory authorized dealer but I would expect them to charge for their diagnostics. I thought my dealer was factory authorized Carrier says no.

Would you have a suggestion for new wiring? Something better than normal thermostat wire? Just in case tightening the splice doesn't prove to be a final fix.

Thanks

 

I would get the installation manuals for the furnace, thermostat and any other equipment and follow the recommendations made in the manuals for installing each piece of equipment.

 

The manuals do not require it but I would pull shielded thermostat wire if this problem persists and you have already replaced the boards.


http://www.docs.hvacpartners.com/idc.../25hpa-3si.pdf

Use No. 18 AWG color--coded, insulated (35°C minimum) wire.
If thermostat is located more than 100 ft/30.48 m from unit, as
measured along the control voltage wires, use No. 16 AWG
color--coded, insulated wire to avoid excessive voltage drop.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.

http://www.docs.hvacpartners.com/idc.../58cv-11si.pdf
24-V Wiring
Make field 24--v connections at the 24--v terminal strip. (See Fig.
25 -- 34.) Connect terminal Y/Y2 as shown in Fig. 27--34 for
proper cooling operation. Use only AWG No. 18, color--coded,
copper thermostat wire.


http://www.docs.hvacpartners.com/idc.../uid01-4si.pdf

 

Had similar problems with our Infinity system since new in 2010. Ours is a heatpump with gas furnace (hybrid setup) with three zones, stats in each, dampers, and zone control board; all Carrier. Had random comm errors intermittently for years most of which cascaded over a few minutes as comm errors with each component. As of mid January have had zero errors after doing the following:

1. Eliminated all instances where control wiring had multiple conductors under the board screw terminals. Did it by having only single conductor under each screw and then wire nut connections to join the various lines from system components. The board connections do not like multiple conductors.
2. Ran new shielded control wire from exterior unit to the zone control board and rerouted it to avoid exterior unit 240V power line (actually all power lines). Original was strapped to the refrigerant lines which had it pinched at the wall penetration and routed directly along the exterior 240V power to the unit. Used wire typically used for fire alarm use with 4 conductors, overall shield, and drain wire for ground.
3. Ran same shielded wire from furnace/fan coil unit to zone control board. Also rerouted because the installer ran the original through the fan compartment near transformers and variable speed fan motor instead of using the instruction location for control wiring entry. Left all other control wiring to stats and dampers as is with normal stat wire but made sure that it was not along power cables within the house.

I will update if the problem returns but this comprehensive revision has me pretty sure that the problems were control line noise and/or connections. I think installers just aren't used to these control systems where digital signals, addressable components and constant data transfer between units makes signal/noise a big problem.

 

Update to 3/16/13 status:

Intermittant problem returned after approximately a month and resorted to having technician come out. Replaced zone board under warranty (cost me $200 labor) and that lasted about a month until problem returned. Last week resorted to replacing user interface wiring to zone board with shielded wire and found the user interface case had become partially open (possibly from temporary removal during house constraction for some reason, who knows since I do not know of it being removed for any reason since move in). I clicked it back together and so far after approximately a week, zero problems and the system seems to respond to commands quicker (imagination).

So, assuming it is now fixed, the problem could have been noise, could have been wire connections at UI or zone board or could have been UI partially disassembled. Lesson is that the simplest thigs such as these can cause very difficult diagnoses.

 

I have installed many of these systems and it is not a normal problem. Shielded wire is not needed. You either need new wire ran because you have a splice you do not know exists or you could have a bad place in the wire which may show up on occasion. Or it could be to small of gauge wire considering the distance between the indoor and outdoor unit.

 

I had same problem, intermittent communication with outl
Door out unit. Finally replaced the ac board. All seemed to work well.

However I have had. Communication action errors 3 times since then. I found it happened mostly when I tried to change the basement temperature from the main infi.ity control. All wires were replaced and main controls board pig tailed to fix initial problem.

 

We have installed hundreds of these systems without shielded wire without a problem but there has been a few that we had to go back and run shielded wire.