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Before treatment, its “pH” is typically in the 3.5 to 6.0 range.
Handling and disposal of condensate is not complicated, but it must be done correctly to prevent problems or complaints. A trap/neutralizer assembly is provided with the heater to simplify installation. This assembly is easily installed in the base of the heater. Figure 11 illustrates its installation and the routing of drain tubes.
To install the condensate assembly, first install the short length of 5/8" I.D. tubing on the barbed fitting on the bottom of the condensate collector. Then drop the condensate tray into the opening in the base pan of the heater, bending the 5/8" tubing as necessary to get the tube into the tray. Readjust the 5/8" tubing so that its lower end is 1/4" - 3/8" above the bottom of the tray. The tray can be positioned with the outlet fitting to the right, as shown in Figure 11, or with the fitting to the left, depending on the direction required for condensate disposal. Connect the piece of 1/2" I.D. tubing to this outlet fitting and route it out of the heater through the hole in the side of the base panel. This tube carries condensate to the drain. If this disposal tube is routed to the left, remove the plug button from the hole on the left side of the base panel and push it into the hole on the right side.
Connect the remaining short piece of 3/8" I.D. tubing to the barbed tee fitting in the tubing immediately in front of the blower. Position this tubing so that its bottom end is
A package of limestone gravel neutralizer is provided with the condensate assembly. Place this gravel in the tray after installing and properly positioning all tubes. Be sure that a limestone pebble does not plug any of the tubes. Place the cover on the tray when this is done.
It is important that there be no sagging sections of tubing to trap water. Drainage to the trap and out of the trap to the drain must be assured by continuous downward routing of these tubes. It may be necessary to elevate the heater to provide downward routing. The outlet of the disposal tube must be open to the air.
If a gravity drain is not available, a condensate pump must be provided in the field. Suitable condensate pumps are available commercially at air conditioning equipment distributors.
Incorrect installation of the condensate assembly or tubing can result in overflow or waterlogging of the vent. In normal operation, water accumulates in the tray at the level of the outlet fitting, and this provides a “water seal” which accommodates combustion system pressures. Figure 12 illustrates the water seal. Note that water is “pulled” up toward the condensate collector pan and is pushed down slightly by the vent/
blower drain. If there is no water seal, air rushes into the collector drain, preventing normal drainage of condensate water, until vent drainage provides the seal (see Section 2L,
The installer must be sure to take whatever measures are necessary to prevent property damage by condensate overflow. If the heater location is such that this water can directly or indirectly damage a building, furnishings or other property, an overflow pan or other appropriate preventative measure should be provided.
2I. Gas Supply and Piping
Before installing gas piping, check the rating plate on the heater to be sure that the heater is for use with the correct (available) gas. Make sure that gas supply pressure is adequate per the requirements in Table 4. Note that the system must be capable of providing these pressures while the heater is operating.
Supply Pressure | Minimum | Maximum |
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Natural Gas | 5 Inches WC | 10.5 Inches WC |
| (125 mm WC) | (265 mm WC) |
LP Gas | 11 Inches WC | 14 Inches WC |
| (280 mm WC) | (350 mm WC) |
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Table 4. Gas Supply Pressure Requirements
Gas piping must be large enough to provide the required gas flow rate without excessive pressure drop. Table 5 specifies pipe sizes which will limit pressure drop to 0.5 In WC (125 Pa), based on the National Fuel Gas Code, ANSI Z223.1.
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220 | 1" |
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| 3/4" | 1" |
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350 |
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| 1" |
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Table 5. Required Gas Pipe Size
Support gas piping properly so its weight does not bear on the heater. Install a drip leg, a non- restrictive shutoff valve and a union on the gas supply line outside of the heater (see Figure 13).
Before operating the heater, test the gas supply system, including all connections, for leaks using a soap solution. Do not use a flame or any ignition source for leak detection. Disconnect the heater and its individual gas shutoff valve during pressure testing if the test pressure is higher than 1/2 psig (3.34 kPa). If the pressure is 1/2 psig (3.45 kPa) or lower, close the manual valve on the heater gas control during testing.