NOTICE
When possible, domestic hot water production should utilize dedicated boiler(s). This will allow the other boiler(s) to be shut down and isolated during the summer months. If the boiler load is shared between heating and domestic hot water, then one needs to determine if a hot water priority is required. If a priority is not selected, erratic domestic hot water production may result during the beginning and end of every heating season. Conversely, a priority for domestic hot water production may cause a significant heating zone activation delay, in an improperly balanced system. Parallel piping conversions may require isolation from the heating system to prevent system flow influence on DHW performance. Consult a qualified system heating professional to design for the proper application.
C.BOILER PIPING, DOMESTIC HOT WATER (DHW) APPLICATION – The MPC boiler can be used in many different piping applications to produce Domestic Hot Water (DHW). In some applications, depending on the control strategy (outdoor reset, setpoint operation, etc.) and size of the boiler, it is recommended to isolate the space heating load from the DHW load. For example, if the domestic load is more than the space heating load, it is beneficial to dedicate one or more boilers solely to DHW production and one or more boilers solely to space heating, since during mild weather conditions, the boiler(s) will have more capacity than is required. Piped in the recommended manner, the space heating boiler(s) can be shut down during the summer months to conserve energy and to avoid short cycling.
The use of indirect water heaters for domestic hot water generation is commonly recommended since they provide DHW storage. A tempering valve and recirculation loop are advantageous in these applications, because they provide both high temperature and tempered domestic water to the
system, eliminating the need to purge and waste water until it reaches the desired temperature. See Figures 49a, 49b, 50a and 50b for recommended indirect water heater piping.
NOTICE
DO NOT use the boiler circulator as an indirect domestic hot water system circulator.
D.Relief Valve Discharge Piping, see
Figure 54. Pipe discharge to within 4” of floor or to a suitable drain. Do not reduce piping size or install shut- off valve in discharge piping.
If discharge is weeping, do not plug relief valve or cap discharge piping, replace valve immediately.
E.INSTALL ELECTRIC WIRING in accordance with National Electric Code and local regulations. A separate ELECTRICAL CIRCUIT should be run from meter with a Fused Disconnect Switch in this Circuit.
Figure 54: Discharge Piping for Pressure Relief Valve
64
