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Apollo HydroHeat: The Inside Story
How does it work?
The Apollo system uses a gas water heater to furnish both domestic hot water and warm indoor air. A recirculating loop of hot water is tapped off near the top of the heater and is sent through a finned tube heat exchanger in an air handler that furnishes warmed air. The cooled water (140° F cooled to 120° F) is then returned to the water heater near the bottom of the tank. Each Apollo air handler includes a circulating pump and controls that are factory-piped and wired. (See Figure 1.)
The Apollo system is easy to control using a conventional thermostat. On a call for heat, the hot water circulator and blower motor are energized through a relay. Hot water immediately begins circulating through the heat exchanger to heat the air. Typical exiting air temperatures are 100° – 105° F. When the thermostat is satisfied, the pump and blower both stop.
How is an Apollo system sized?
First, have your contractor determine the design heat loss of the home by consulting ACCA Manual J. The heating capacity of the air handler must be equal to or greater than the design heat loss. The water heater selected must likewise have a heat output equal to or greater than that of the air handler.
To calculate the minimum BTUH input needed, divide the air handler heating capacity by the recovery efficiency of the water heater. Here’s an example:
ACCA Manual J shows that a home has design heat loss of 27,480 BTUH. You select an Apollo air handler with heating capacity of 30,000 BTUH and a water heater with 85% recovery efficiency.
30,000
.85 |
= 35,294 BTUH minimum water heater input |
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For proper sizing, you would need a 40,000 BTUH input water heater to meet minimum needs.
Does the Apollo HydroHeat system require a larger tank size?
No. With Apollo, you can get ample space heat and hot water with a 40-gallon tank, which is a typical size in most homes.
Will I ever run out of hot water?
Not if your system is properly sized. You should always have plenty of hot water and warm air for your rooms.
Do I have to run the water heater at higher temperatures?
No. Apollo HydroHeat units are rated at normal domestic hot water temperature of 130° – 140° F. It is not necessary—or recommended—to set the temperature higher than that.
Where needed, domestic hot water temperatures can be lowered with the use of a mixing valve.
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