The setup:
1. Have a 2001 house which had a poorly sized unit (2 ton for 1300sf)
2. Contractor A installs new HVAC upsized to 3 ton. Money was spent for a new condenser, heater, and compressor.
3. Front room does not get enough warm air to keep one-year old son warm during winter.
4. Wife calls Contractor B for an invoice and review of the system. ConB states returns were not upsized for the larger 3 ton unit and the unit is being choked out and therefore not generating enough pressure in supply plenum to pressure son's room (the longest run). ConB also states that he thinks a return plenum would help out a bunch too. ConA and original setup did not have return plenum.
5. I get ConA back out and he does not think that the returns are the problem. However, he does install a damper on the Master Bedroom supply ( it was often too hot) and an air scoop on the son's supply line at his cost. This seems to have helped a bit but not completely.
Now I'm a trained civil engineer. I understand fluid dynamics and friction losses. I understand capacity and air flow. What I don't understand/have time to look up myself is what your average 3-ton unit needs on the return side and the efficacy of a return plenum.
The facts:
3-ton unit
current 8" return from master bedroom
current 14" return from hall (where thermostat is located)
Con B wants to 8>12 and 14>16
HVAC Contractors and/or MechEs, what say you? Who is blowing hot air or can't tell?
1. Have a 2001 house which had a poorly sized unit (2 ton for 1300sf)
2. Contractor A installs new HVAC upsized to 3 ton. Money was spent for a new condenser, heater, and compressor.
3. Front room does not get enough warm air to keep one-year old son warm during winter.
4. Wife calls Contractor B for an invoice and review of the system. ConB states returns were not upsized for the larger 3 ton unit and the unit is being choked out and therefore not generating enough pressure in supply plenum to pressure son's room (the longest run). ConB also states that he thinks a return plenum would help out a bunch too. ConA and original setup did not have return plenum.
5. I get ConA back out and he does not think that the returns are the problem. However, he does install a damper on the Master Bedroom supply ( it was often too hot) and an air scoop on the son's supply line at his cost. This seems to have helped a bit but not completely.
Now I'm a trained civil engineer. I understand fluid dynamics and friction losses. I understand capacity and air flow. What I don't understand/have time to look up myself is what your average 3-ton unit needs on the return side and the efficacy of a return plenum.
The facts:
3-ton unit
current 8" return from master bedroom
current 14" return from hall (where thermostat is located)
Con B wants to 8>12 and 14>16
HVAC Contractors and/or MechEs, what say you? Who is blowing hot air or can't tell?