Dunham bush 24000btu casette.

Please help.

I have a client with three (3) dunham bush casette airconditioners. Below is the model numbers of one of them:

Indoor CS704M
Outdoor PH24c.

All three units are identical and are showing the same problems, i.e they are not cooling and show the same symptoms which are as follows:

Suction pressure 60 psi
Discharge pressure 150 psi.
Condensor discharge air temp is ambient.
Evapourator discharge air temp is ambient.

From what I can tell, there is no restriction taking place at the evapourator i.e. refrigerant is just circulating through the pipes.

Apparently I am the third tech to work on the units, the other two gave up. The client says the aircons have not worked from day 1.

I just cant believe three AC's in the same area are defective.

I have received no help from Dunham Bush.

Believe it if they haven't worked from day one.

What refrigerant is in the units?

If there are service valves fitted try closing down the discharge, liquid, line to simulate an expansion valve. See if you get a temperature drop across it.