I.CONNECT TANKLESS HEATER PIPING AS SHOWN IN Figure 12. See Table 3 for Tankless Heater Ratings.
Figure 12: Schematic Tankless Heater Piping
Table 3: Tankless Heater Data
Boiler | Rating (Gal/Min) | Pressure Drop | |||
(PSI) | |||||
Model |
|
| |||
Steam | Water | Steam | Water | ||
| |||||
2.25 | 2.75 | 2.3 | 3.9 | ||
2.25 | 3.00 | 2.3 | 4.7 | ||
2.50 | 3.25 | 3.1 | 5.6 | ||
2.50 | 3.25 | 3.1 | 5.6 | ||
|
|
|
|
| |
2.75 | 3.75 | 3.9 | 7.2 | ||
3.00 | 4.00 | 4.7 | 8.0 | ||
2.75 | 3.50 | 3.9 | 6.4 | ||
3.25 | 4.25 | 5.6 | 8.8 | ||
3.50 | 4.75 | 6.4 | 9.6 | ||
THE FOLLOWING GUIDELINES SHOULD BE FOL- LOWED WHEN PIPING THE TANKLESS HEATER:
1.FLOW REGULATION — If flow 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 flow regulator matching the heater rating should be installed in the cold water line to the heater. The flow 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 flow regulator also limits the flow 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 fixtures. In
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 fixtures. 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 beneficial to the tankless heater but to piping and fixtures plus the many other benefits derived from soft water.
J.INSTALL SMOKEPIPE — The CL Series boiler should be vented into a fireclay
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 efficiency 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 fired or an inefficient oil fired boiler built into a home without insulation or storm windows. With increasing fuel prices that home probably has been insulated and fitted with storm windows so that
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