Lochinvar SDT/SET065 - 119 9High Output Piping, High Domestic Hot Water Usage, Series Piping

SDT/SET Installation & Operation Manual

9High Output Piping

High Domestic Hot Water Usage

When a large amount of hot water is required by a Domestic Hot Water system, the dual coil indirect water heater can be piped together when given the high volume needed to satisfy the high load demands. This is achieved by piping the boiler coil and solar coil together. This will enable heat transfer to both the heat exchangers at the same time. This is done by series piping or piping in parallel. A decision must be made to choose a particular system based on the heating coil pressure drop and the desired flows. This type of piping can be done in a solar operation as well as with a boiler to acheive this maximum heat transfer into the water.

Series Piping

With this style of installation, the solar / boiler supply piping is connected to boiler water IN connection. When joining in this operation, all fittings must be no smaller than one-inch in size. Then, the boiler water OUT and the solar water IN are connected. This will join the boiler and soiler coils together. The return water is piped from the solar return to the solar / boiler supply. See FIG. 9-1 on page 26.

NOTICE	For tank operation use the lower
	bulbwell to turn the tank on and off.

Parallel Piping

With this style of installation, both heat exchanger are used at the same time. Solar / boiler supply piping to the solar water IN and boiler coils will be at the same temperature at the same time. Then, the boiler return and the solar return are piped together again to return the water to the heat source. See FIG 9-2 on page 27.

NOTICE	For tank operation use the lower
	bulbwell to turn the tank on and off.

The two-pipe reverse return hydronic loop is more balanced and even than the two-pipe direct return hydronic loop. Both heat exchangers receive the same temperature of water so it is the same as the two-pipe return, but with more advantages. One advantage over the two-pipe system is a balanced flow of the reverse return system. This system can have a lower pressure drop for both heat exchangers than the two-pipe system, and it also requires less energy.

25