The maximum BTU output of the P-Supply-1U-48 is 136.5 BTUs and that is when the full 7.5 amps of its sourcing capability is being used.
Powering one end of a standard Apex, GigaPlus or Giga Link max is only 7.92 BTUs (about 1.5 amps being sourced).
For one end of GigaPro worst case is approximately 19.1 BTUs max with 2 HP ODUs attached (3.625 amps being sourced).
ApexPlus and GigaPlus BTU output is about 119 BTU plus the output of the power supply (above). GigaPro is about 238 BTU.