Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website.. 96 Math for HVACR f 2. How much water will l Zone 2 hold? __________ gallons 3. How much water will Zone 3 hold? __________ gallons 4. How much water will Zone 4 hold? __________ gallons 5. If the boiler installed in this building holds 17 gallons of water, what is the total system capacity, to the nearest gallon? __________ gallons