Installation / Operation Instruction Manual

Pre-installation continued-

IMPORTANT DECISIONS REQUIRED BEFORE

INSTALLATION

SIZING

1. Boiler DOE Heating Capacity – The indirect-fired water heater

will provide the rated performance only if used in conjunction

with a heat source with a DOE heating capacity (Heat Output) at

least as much as the minimum noted in Table 3. If the heat

source has less capacity, the output of the tank will be reduced.

To determine the approximate reduction in output from the tank

use the following formula:

New Rating = (maximum continuous draw rating) x

Actual Output of Heat Source

Minimum Output of Heat Source

For example, what would the continuous draw rating be if a 50-gallon

indirect-fired water heater were installed with a heat source having a

DOE heating capacity of 50,000 BTU/h?

Answer:

New Rating

= 85 gal/hr x (50,000 BTU/h)/(58,000 BTU/h)

= 85 gal/hr x 0.862 = 73 gal/hr

NOTICE

Increasing the boiler DOE heating capacity above the values listed in

Table 3 will not increase the rating of the water heater.

2. Circulator Sizing – Refer to Table 5 for the corresponding

pressure drop through the coil for the given model. Calculate the

pressure drop of all straight pipe and fittings on the supply and

return of the water heater at the selected flow rate. Add the

piping/fitting pressure drop to the pressure drop through the water

heater coil.

Select a circulator that will provide an appropriate flow rate at the

combined pressure drop.