Trane rtu reheat problems

[carman]

Trane TCD241c40rcb I am having trouble with this unit on circuit 1. The reheat valve which has been replaced by a previous company doesnt seem to be working. I do not have much training on this unit and would like some help please. The suction line is freezing up as well as the equalizer tube from the center. The head pressure is below normal but suction pressure drops to 0. This valve is stuck i suppose. Has anyone had this problem. This is in cooling operation not calling for reheat. I run test on it and it will never go into dehumidification mode. But the main problem is i think the valve is stuck and the normal cooling mode is restricted. What do u guys think.

[jayguy]

Service bulletin: RT-SVB33A-EN states

Unit models affected are 3 through 5 ton YHC and THC units.
Units affected by this bulletin are serial numbers starting with 317 through 731 with the hot gas reheat option installed. This option is designated with a “B” in the 22nd digit of the model number.

the valve is stuck and needs to be replaced. if has already been replaced, it is possible that the small tube has been 'brazed over' when installed. i found one that the factory had brazed it shut but i replaced it anyway.

[carman]

Thanks Jayguy. I ordered the part and should have it this week. I didnt think about the equilizer tube being restricted. When i install the new valve i will also check the tube for obstruction. Looks like a pain to changeout as do all the reversing valves out there. Thanks alot ill keep you guys posted.

[carman]

ok i installed the reheat valve today and still having problems. same as before. head pressure stays at 150 psi and suction goes to 0. when valve is switched suction pressure goes to 125 and head stays the same 150. when at 0 psi suction line is frosting up and discharge line is terribly hot. Its whooping me. Help is needed. is there a check valve somewhere that i dont see that may be stuck?

[dd98724]

Is the line from the HGRH valve to the HGRH Coil hot? Are you getting voltage to the solenoid? Your issue may not be reheat related.

[carman]

The line was not hot and yes I have 27 volts to coil. When I run test circuit 1 with reheat in cooling mode suction is 0. Head 150. The funny thing is when harness to coil is off I have 27 v when I put harness on coil it reads 0 v. I'm gonna call trane tech support tomorrow and figure this out. Atleast the other circuit is running fine.

[jayguy]

the attached piping diagram shows both refrigerant circuits for your unit.

Circuit #1 is highlighted in red (i only highlighted 1 tube in each of the heat exchangers).

while in the cooling only (non dehumidification mode) with a 0 psig suction, your only reasons for a restriction are the txv and the liquid line filter drier (assuming no restriction in the evaporator).

i circled the check valve, but it only comes into play in dehumidification mode.

[jpsmith1cm]

1acman,

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