Cab Heat / Air Conditioning Issue

[KiotiTom1231]

2018 RX6620PC. In addition to the very painful learning curve in plowing snow up/down a gravel hill this past winter, I had to deal with the new machine not allowing the heater and air conditioning to run at the same time. With the heat on full, the interior windows would completely fog up. Hit the AC button on and the air would immediately blow cold. The cold dry air conditioned air would then clear the condensation on the windows, but I would then be freezing my butt off. Hit the AC button off and I would warm up but the moisture on the windows would return.

Dealer said "crack the windows open to let some air in". NOT something you tell someone that just spent the extra $$$ on a heated cab! Just the same, tried it and it did not work.

Air in the HVAC system: Blows from the fan, through the AC evaporator core, either through or around the heater core, then into the cabin. There are two doors tied together in the HVAC system between the AC evaporator core and the heater core that do only one of two things at a time: Either divert ALL air through the heater core or divert ALL air around (bypassing) the heater core, there is no in between or mixture - either fully closed or fully open. When the AC button is turned on, in addition to enabling the AC compressor, those doors divert ALL air around (bypassing) the heater core, when the AC button is turned off, in addition to disabling the AC compressor, those doors divert ALL air through the heater core. Temperature adjustment is achieved by a stepper motor solenoid regulating the amount of coolant flowing through the heater core.

Anyone having this issue? I find it difficult to believe I am the only one with this issue.

 

[Kioti Paul]

It sounds like it is operating as designed. In my opinion-- a very bad design! There have been a couple of threads where people install aftermarket heaters / window defrosters.

Seems to me that it should be pretty easy to modify the wiring - which if Kioti discovers it, will almost certainly void any warranty (whether or not the modification had anything to do with the warranty claim).

The simplest modification would be to unplug the compressor, then run a different wire from the alternator battery lead to the compressor, then to ground. Preferably find an identical plug (many automobiles use the same compressors). otherwise .250 female spade connectors should work. OF COURSE, do NOT cut, mutilate, or modify the original plug or wiring!!! just fold back out of the way (That goes without saying,,,right??)

If you do that, be sure to have a fuse in the positive lead. Plus be sure to remember that the compressor will ALWAYS be engaged, even when the tractor is off (and when cranking)...you will have to unplug the compressor anytime you don't want it running.

Obviously, this is not an ideal fix; but it is quick, easy, and can be (quickly and easily) removed anytime you need warranty work. In addition, I would bet that the conditions where you need the compressor to run with the heater on are few and far apart (if the outside temp is below 35 it won't do any good to run the comp), so for the most part you would just keep the original wiring plugged into the comp.

When the tractor is out of warranty, with a little snooping, it should be quite easy to add an additional switch in parallel with the AC button to either keep the comp on even with the AC button off, or to keep the diverter doors in the heat position with the AC button on.

 

[KiotiTom1231]

That is the same conclusion I came to - operating as designed, just that the logic of the design is badly flawed. The official fix for this would be a change in the code of the controller. The major problem is how in the world do you get Kioti to make a code change like that? The dealer does not appear to be interested in helping. Anyone have contacts direct into Kioti that I could consider pursuing?

Thanks for the workaround suggestion, but the workaround I have implemented is even simpler. Turn the AC off thereby causing the doors to divert the air through the heater core, then unplug the stepper motor that moves those two doors. Now when you turn the AC on those doors do not move to divert the air around the heater core. Problem is I will have to do the unplug every fall, then plug it back in every spring. When out of warranty I could probably install a switch to control that circuit. But really, it would be nice to have it work the way it should.

Still interested in knowing if anyone else is experiencing this issue? Hard for me to believe I am the only one plowing snow in the winter with an RX6620. The orange beast is parked in a 47 degree shop with doors and windows open to let the shop heat dry it out. But once I track in a little snow from my boots, that snow melts and the moisture fogs up ALL the windows. The heater by itself does not cut it, has to have that dry conditioned air to get the moisture off the glass.

 

[KiotiTom1231]

According to my email, someone replied to this thread with "Got it fixed under warranty on my 17 NX". Cannot tell who it is, and I do not know why I am not seeing it here, but can you tell me what specifically they did to fix it?

 

[grsthegreat]

thats weird, my 2010 DK45 can run the heater and when i click on the ac button, i can get rid of the condensation while still getting hot air. i can adjust the temp with the temp dial. Bu running the ac mode, im simply bringing the condenser into play to remove the condensation. i dont know why yours doesnt do this.

 

[NetbyTractor]

That was me. They installed some kit of parts..not sure of the complete content.

 

[kmwahoo]

Mine is doing the same wtf do I do? Please help asap

 

[kmwahoo]

Help me mine is doing the same thing. Fogging up.

 

[kmwahoo]

First time running mine in the snow and it's doing to me. Help

 

[Kioti Dave]

Mine is doing the same wtf do I do? Please help asap

https://www.tractorbynet.com/forums/kioti-owning-operating/415478-nx4510-hst-cab-c-issue.html

Here is a discussion on that issue. It is on page 2. On my NX4510, I had a kit installed on warranty that will allow you to run A/C and get heat at the same time. Has made a huge difference. My windows will be fogged up, and all I need to do is turn on A/C and the windows clear in less than a minute. I also use a 12 volt fan that I plug into the 12 volt outlet. The kit number is in the other discussion. Kioti installed on warranty a month ago.