Carrier high efficiency units
Unlike some other brands carrier some what made it easier to diagnose using the old OBD1 vehicle diagnostics L.E.D Flashing systems.
In this article I will cover diagnostics characteristics ,parts location and also cover more curiosity that you technicians many have some manufactures started building this high-efficiency units using one main board meaning inverter is combined with control systems also,so when one goes bad you must replace the whole board kinda like your uncles TV VCR combo or your mothers dryer washing machine together she refuses to get rid of.
Well carrier has two boards in their green systems meaning you can replace them one at a time they say the inverter is something you hardly would have to go into.
The 25VNO Heat pump condensing unit has a variable speed compressor,Infinity communication controls,variable speed drive,Highest efficiency,air source heat pump,HSPF,S UP TO 13,AND seer up to 20.5.
The benefits of it are:
Comfortable supply air temperatures,less dependency on auxiliary heating,performance approaches water source heat pump,at 17 degrees F’ THE VARIABLE SPEED HAS 86% More capacity 29% more efficient than the competitor I’m not here to promote this product lets move on.
Look below at the model numbers notice the change more like a car’s vin number every letter means something
Notice the board below has terminals such as ABC
to hook up thermostat wires for Both high and regular efficiency on the right of the right side.
Notice the contactor below
Notice it has a muffler which is needed during high-efficiency mode
By now you get the picture this is new to all of us although you may have installed one or two it takes a few years for them to start breaking down so diagnostics knowledge know how is a must.
In any event you have to remove any wiring be sure to put them back exactly the way you’ve taken them out if they were looped loop them back the same way
L E D Flashing diagnostics so you would refer to your code chart
Living in florida what really concerns me is lightning:
by now you are probably thinking arrestors ,resitors of all types that can stop lightning from damaging these units! Yes that’sthe way technicians think ”A solution to the problem” But there are many ways the high voltage can travel to enter the unit maybe from a chain link fence. (National Electrical Code (NEC) requires you to install a second rod at least 6 ft away from the first rod, if the resistance of the first rod is greater than 25 ohms) or any other paths .My own solution is to use an earth ground away from the house ground as far as you can . you can use multiple rods personally I prefer copper because of its conductivity.
TO BE CONTINUED