Live in Mobile and have been doing some research regarding temperature difference between the ac supply and return air and I have few questions:
1. Should a proper running system have difference of 15-20 degrees between return minus supply regardless if measured during the day or night?
2. Is it standard practice to measure this difference after a new install?
Asking because I had an entire unit replaced late last summer (indoor and outdoor) and it now does not cool properly. I checked the temperatures after running the system for at least 30 minutes at the return and supply, not at the plenum but at the first 2 registers leaving the unit. During the afternoon the return is 70 and supply is 61 and at night the return is 70 and supply is 50.
3. What could cause such a difference between the night and daytime temp checks?
I want to say the unit is sucking hot daytime attic air at a point past the coils. Thinking the new unit is not the same length (shorter) as the old and do not know how they closed the gap or if it was done properly. The unit installed is a Goodman 4t which replaced a 1987 Bryant 4t.
I called the HVAC installer this past Monday (11th) and they had to add 2 pounds of 410 to the system because according to the tech, the installer did not properly tighten valve stems after removing during the soddering of the supply line. Planning another call but just want some information from those in the HVAC field before doing so.
Thanks
1. Should a proper running system have difference of 15-20 degrees between return minus supply regardless if measured during the day or night?
2. Is it standard practice to measure this difference after a new install?
Asking because I had an entire unit replaced late last summer (indoor and outdoor) and it now does not cool properly. I checked the temperatures after running the system for at least 30 minutes at the return and supply, not at the plenum but at the first 2 registers leaving the unit. During the afternoon the return is 70 and supply is 61 and at night the return is 70 and supply is 50.
3. What could cause such a difference between the night and daytime temp checks?
I want to say the unit is sucking hot daytime attic air at a point past the coils. Thinking the new unit is not the same length (shorter) as the old and do not know how they closed the gap or if it was done properly. The unit installed is a Goodman 4t which replaced a 1987 Bryant 4t.
I called the HVAC installer this past Monday (11th) and they had to add 2 pounds of 410 to the system because according to the tech, the installer did not properly tighten valve stems after removing during the soddering of the supply line. Planning another call but just want some information from those in the HVAC field before doing so.
Thanks
