18
2)
Flow Restrictor (Recommended) - If water is drawn from the tankless coil at a rate in excess of the rating in Table 1b,
the temperature of the hot water may be too low to be of use. The use of a flow restrictor will prevent this problem by
limiting the rate at which water can pass through the tankless heater. If a restrictor is used, select one having a rating
in GPM approximately equal to the rating shown in Table 1b. If possible, locate this restrictor at least 3 feet from the
tankless heater inlet so that it is not subjected to excessive temperatures when no water is flowing through the coil.
3)
Pressure Relief Valve (Required) - Limits the pressure in the tankless heater and piping. Use an ASME constructed valve
designed for domestic water service, such as the Watts #3L. 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 the working pressure marked on the tankless coil. Pipe the
discharge to a safe location using piping the same size as the discharge connection on the valve.
4)
Hose Bib Valves (Recommended) - These valves permit the coil to be periodically “backflushed” to remove sediment.
TANKLESS HEATER PIPING
KSZ Series boilers equipped with tankless heaters are supplied with a Honeywell L4006A limit control and a 3/4 NPT
well. For shipping purposes, these components are shipped unmounted. This control is mounted in the 3/4 tapping in the
center of the tankless coil.
Make the piping connections to the coil before installing the L4006A. When making the “OUT” connection, make sure
that the piping is routed so that it will not interfere with the L4006A.
Pipe the heater as shown in Figure 12b. The components in this system and their functions are as follows:
1)
Tempering Valve (Required) - During the heating season, the water exiting the tankless heater may be 180 degrees or
more. The mixing valve blends hot water leaving the tankless heater with cold water so as to maintain the hot water
supplied to the fixtures at a fixed temperature. This saves energy, increases the amount of usable hot water available to
the homeowner, and reduces the risk of scalding.
Install a mixing valve with a setting range of approximately 110 to 130F. Follow the manufacturer’s instructions for
installing this valve. Usually a “heat trap” will be required between the coil and the “hot” connection on the mixing
valve.
IMPORTANT
• Some indirect water heaters may not be suitable for use with a steam boiler. Consult the
water heater manufacturer’s guidelines before installing it in this type of system.
• Boiler water temperatures and flow rates in this type of system may be considerably lower
than those upon which the water heater manufacturer’s ratings are based. This may result
in substantially longer water heater recovery times.
DANGER-SCALD HAZARD
The control supplied with this boiler is not intended to provide accurate control of the
domestic water temperature leaving the tankless heater. An installer supplied, ASSE 1017
or ASSE 1070 certified tempering valve is therefore REQUIRED as part of this boiler’s
installation.
• Select, and install tempering valve in accordance with the valve manufacturer’s
instructions and applicable local codes. In the absence of such codes follow the
Uniform Plumbing Code (IAPMO/UPC-1). Also note that additional tempering valves
may be required at the fixtures themselves.
• Adjust low limit and tempering valve to the lowest practical setting.
• Feel water before showering or bathing.
Summary of Contents for KSZ Series
Page 2: ...2 ...
Page 24: ...22 FIGURE 15 TWO PIPE GRAVITY FEED SYSTEM FIGURE 16 TWO PIPE LIFT SYSTEM ...
Page 37: ...35 ...
Page 39: ...37 ...
