Weatherking model 13pja36a01 heat pump not cooling house enough, this is a used system only 4 years old, cools house good at night, but not enough during the day. I am the only source of income in my house right now and cannot afford repairs, this unit was given to me and installed by a good Samaritan. The pipe's will get cold and damp - not freezing up - then after a while they will just be cool and not damp, have replaced filter and cleaned inside/outside coils. My old system would keep the house at a constant level of comfort with a/c before it died. Any thoughts on this problem.

It probably doesn't have enough capacity. The key is it works at night, but the daytime solar load is too great. Make sure you have plenty of insulation, all windows sealed.