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WARNING
Like all domestic water heaters, the MWC is capable of generating water that is hot enough to
cause injury or death due to scalding. To minimize the risk of scalding:
Set domestic hot water (DHW) thermostat as low as possible (see the Start-up Section of this • manual for the location of this thermostat.
Feel water before showering or bathing.• If anti-scald or anti-chill protection is required, use devices specifi cally designed for such • service. Install and maintain these devices in accordance with the manufacturer’s instructions.
X. Domestic Water Piping
If the MWC is equipped for domestic hot water (DHW) production, connect the domestic hot water piping
as shown in Figure 10.1. Connections to the boiler are made with 1/2” copper tail pieces as shown in Figure
10.2. Solder the fi rst fi tting to these tail pieces before mounting them on the boiler. The components in this
system and their functions are as follows:
Anti-scald Devices 1) (Required - Not Shown) - Install anti-scald protection devices in accordance with local
codes. In the absence of any local Codes, install such devices as required by the Uniform Plumbing Code
(IAPMO UPC).
CAUTION
If the MWC is connected to a water supply having a hardness in excess of 200PPM, scale
may prematurely form in the DHW heat exchanger, signifi cantly shortening its life. If
necessary, soften the water upstream of the cold water connection to the MWC.
Flow Restrictor (Recommended)2) - If domestic hot water is drawn from the MWC at a rate in excess of
the rating in Table 2.2, the temperature of the hot water may be too low to be of use. The use of a fl ow
restrictor will prevent this problem by limiting the rate at which water can pass through the DHW heat
exchanger. If a restrictor is used, select one having a rating in GPM approximately equal to that shown in
Table 2.2.
Pressure Relief Valve (Required)3) - Limits the pressure in the domestic hot water piping. Use a valve
designed for DHW service, such as the Watts #3L or #53L. Note that this is a pressure relief valve, not a
T&P valve. Select a valve with a pressure setting less than or equal to 145 psi. Pipe the discharge to a
safe location using piping the same size as the discharge connection on the valve.
Hose Bib Valves (Recommended)4) - These valves permit the DHW plate heat exchanger be periodically
“back fl ushed” to remove sediment.
Globe or Ball Valve (Recommended)5) - Used to aid in back fl ushing the heat exchanger and to isolate the
DHW piping if it must be serviced. In addition, the upstream valve may be used to limit the DHW fl ow if
necessary.