l3430 expansion valve

[captaing]

i have the roof off of the unit and dont see expansion valve in area the parts diagram shows it
is it under the air unit itself?
do i have to pull it out to access the valve or am i just not seeing it?

 

[ruger1980]

I believe it is inside the AC evaporator housing. Do you know for sure yours is bad?

 

[captaing]

no i dont

while running my system my pressure will spike from around 225 to almost 500 on high side
i am assuming this is some sort of blockage and am planning on changing dryer and expansion valve as the two easiest options

i am open to suggestions on what else to try!

thanhs

 

[ruger1980]

By spike do you mean that pressure rises and falls quickly or does it rise and stay there? At that pressure your pressure switch should be cutting off your compressor clutch.
I to could be several things. Poor air flow across the condenser, a plugged condenser, sticking or plugged TXV. I think it is less likely the drier as a point of restriction. Has anyone ever charged the system with a sealant?

 

[Hydro]

Put your hand on the smaller of the 2 lines leading into the evaporator box -- is it hot when the pressure has "spiked" ?
-- if so , then the condenser and / or radiator are plugged with dirt -- the pressure line should only be a few degrees over ambient air temperature
-- if heat is not the issue , then too much refrigerant in the system -- all of the refrigerant should "fit" into the high side without "spiking" the pressure

Those tractors have a pretty small evaporator core -- and is easily plugged with dirt / or smoke
-- this will not affect the high pressure , but will affect the ability to cool