Contractor wants to install a fourth TXV on a new system.
I purchased a new Carrier heat pump (25HPA524 and FV4BNF003) at the beginning of the summer. This replaced a comfort series Carrier of the same tonnage. A week or so after the install, the unit had a hard time keeping up. The contractor came out and said the compressor shut off and reset it. He said if it happens again they would replace the TXV because the pressure is too high.
After that I noticed that the system had a hard time keeping up even when the outdoor temperature was in the 80's. We live in the Washington DC area. Thermostat was set at 72 but the indoor temp crept to 74 and sometimes 76. The outdoor fan would run all day even in mild whether and only shut off sometime in the middle of the night until early morning. The contractor replaced the TXV. After that I noticed that the outdoor unit would sometimes have a loud sound and then a low sound. When the sound is high the air coming from the unit fan is hotter than the air outside. When the outdoor unit is quiter the air coming from the fan is the same as the outside air temp. The contractor then replaced the thermostat (TSTATCCPRH01) but the problem still occurred.
The owner of the company (which has a good reprutiation) came out with one of his men and took some measurements and went over the whole system. They concluded that it was another faulty TXV. They replaced it again. The problem still seems to ocur.
The contractor claims that it is yet another faulty TXV. He says they are hit or miss. He has done several new installs some have no problem at all while others they had to replace the TXV several times. He says that when the unit is quite and blows the same temp as the air outside temp the compressor has shut downs due to too much pressure. When the air coming from the unit fan is hot the compressor is running. He wants to replace the TXV again.
All work is under warranty. What do you guys think?