VT climatemaster code 4

[1toobe]

I have a Climatemaster Ultra classic VT series residential Veertical 2 stage Geothrmal Heat pump model VT060GSSSRTDKSH. The a side keeps locking out with code 4. # diffeant heating companys have look at it and change the thermistor #17S0030N01 out two times with the same problem. the thermister is located on the frigerant line betwwen the expansion vale and the heat exchanger. Could there be something wrong with the frigerant systerm? the temp at the thermisor is 30 deg when it locks out.

[buford]

check the install manual the info on the codes are in there.so is the troubleshooting area.

[beenthere]

Moved to geo forum.

[twosticks]

We install Carriers which are made by Climatemaster so I am going to assume some

things to be the same, but they may not be. If your water loop is what is called an open

loop,the unit may be functioning normally. The thermistor is shutting down the unit to

prevent the water coil from freezing. If you have a closed loop with no anti freeze,the

unit is funtioning normally. If you have a closed loop with PROPER freeze protection,

someone didn't cut the jumper (tho' someone should have caught that by now). If a

closed loop, find someone to check the lvel of freeze protection, adjust if needed and

then (and only then) to cut the jumper per instructions.

[1toobe]

I did do the trouble shooting like the book said and changed out the thermister. ohmn out the old thrmister and it was good. Yes this is a open loop systwm. water temp going in is 48 deg and leaving at 41 deg.