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14
I. CONNECT TANKLESS HEATER PIPING AS
SHOWN IN Figure 12. See Table 3 for Tankless
Heater Ratings.
addition, savings of hot water will be achieved since
the user will not waste as much hot water while
seeking water temperature to his liking. Higher
temperature hot water required by dishwashers and
automatic washers is possible by piping the hot
water from the heater prior to entering the mixing
valve. The mixing valve should be “trapped” by
installing it below the cold water inlet to heater to
prevent lime formation in the valve.
WARNING
Install automatic mixing valve at tankless heater
outlet to avoid risk of burns or scalding due to
excessively hot water at xtures. Adjust and
maintain the mixing valve in accordance with the
manufacturer's instructions.
3. FLUSHING OF HEATER — All water contains
some sediment which settles on the inside of the
coil. Consequently, the heater should be periodically
backwashed. This is accomplished by installing
hose bibs as illustrated and allowing water at city
pressure to run into hose bib A, through the heater,
and out hose bib B until the discharge is clear. The
tees in which the hose bibs are located should be
the same size as heater connections to minimize
pressure drop.
4.
HARD WATER — A water analysis is necessary to
determine the hardness of your potable water. This
is applicable to some city water and particularly to
well water. An appropriate water softener should
be installed based on the analysis and dealer’s
recommendation. This is not only benecial to the
tankless heater but to piping and xtures plus the
many other benets derived from soft water.
J. INSTALL SMOKEPIPE — The CL Series boiler
should be vented into a reclay tile-lined masonry
chimney or chimney constructed from type L vent or
a factory built chimney that complies with the type
HT requirements of UL103. The chimney and vent
pipe shall have a sufcient draft at all times, to assure
safe proper operation of the boiler. See Figure 13 for
recommended installation.
1. Install a draft regulator (supplied by installer)
following the instructions furnished with the
regulator. See Figure 14 for draft regulator locations.
2. Consider the chimney overall. Chimneys that have
a high heat loss may become less suitable as the
heat loss of the home goes down and the efciency
of the boiler installed goes up. Most homes have
a chimney appropriate for the fuel and the era in
which the home was built. That may have been a
coal red or an inefcient oil red boiler built into
a home without insulation or storm windows. With
increasing fuel prices that home probably has been
insulated and tted with storm windows so that
Figure 12: Schematic Tankless Heater Piping
Boiler
Model
Rating (Gal/Min)
Pressure Drop
(PSI)
Steam Water Steam Water
CL3-091 2.25 2.75 2.3 3.9
CL3-105 2.25 3.00 2.3 4.7
CL3-140 2.50 3.25 3.1 5.6
CL4-126 2.50 3.25 3.1 5.6
CL4-175 2.75 3.75 3.9 7.2
CL4-210 3.00 4.00 4.7 8.0
CL5-168 2.75 3.50 3.9 6.4
CL5-245 3.25 4.25 5.6 8.8
CL5-280 3.50 4.75 6.4 9.6
TABLE 3: TANKLESS HEATER DATA
THE FOLLOWING GUIDELINES SHOULD BE FOL-
LOWED WHEN PIPING THE TANKLESS HEATER:
1.
FLOW REGULATION — If ow through the heater
is greater than its rating, the supply of adequate hot
water may not be able to keep up with the demand.
For this reason a ow regulator matching the heater
rating should be installed in the cold water line to
the heater. The ow regulator should preferably be
located below the inlet to the heater and a minimum
of 3’ away from the inlet so that the regulator is not
subjected to excess temperatures that may occur
during “off” periods when it is possible for heat
to be conducted back through the supply line. The
ow regulator also limits the ow of supply water
regardless of inlet pressure variations in the range of
20 to 125 psi.
2. TEMPERING OF HOT WATER — Installation
of an automatic mixing valve will lengthen the
delivery of the available hot water by mixing some
cold water with the hot. This prevents excessive
and possibly scalding hot water at the xtures. In