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.