Energy Tech Laboratories DHG240, DHG180 Combustion Discharge, CONTROL WIRE SIZES1, Gas Piping

035-17233-000-C-0702

When connecting electrical power and control wir- ing to the unit, waterproof type connectors MUST BE USED so that water or moisture cannot be drawn into the unit during normal operation. The above waterproofing conditions will also apply when installing a field-supplied disconnect switch.

COMBUSTION DISCHARGE

The products of combustion are discharged horizontally through two screened (hooded) openings on the upper gas

heat access panel.

TABLE 3: CONTROL WIRE SIZES1

Wire Size2

22	20	19	18	16
40	120	150	190	305
	Max. Wire Length3 Feet

1Total wire length is from unit to room thermostat, and back to unit.

2Solid, Class II copper wire.

3Total Wire length is from unit to room thermostat, and back to unit.

GAS PIPING

Proper sizing of gas piping depends on the cubic feet per hour of gas flow required, specific gravity of the gas and the length of run. National Fuel Gas Code Z223.1 should be fol- lowed in all cases unless superseded by local codes or gas utility requirements. Refer to Table 5.

The heating value of the gas may differ with locality. The value should be checked with the local gas utility.

NOTE: There may be a local gas utility requirement specify- ing a minimum diameter for gas piping. All units require a 1

inch pipe connection at the entrance fitting.

GAS CONNECTION

The gas supply line can be routed through the knockouts located on the front of the unit or through the opening pro- vided in the unit's base. Refer to Figure 10 to locate these access openings.

Typical supply piping arrangements are shown in Figures 6 and 7. All shaded items are field-supplied.

Two grommets are shipped in the blower compartment (in parts bag taped to the blower housing) of every unit with gas heat and should be used in the knockouts when the gas pip- ing penetrates the front of the unit.

After the gas supply piping has been installed, the bottom opening in the unit should be sealed to prevent water from leaking into the building.

Gas piping recommendations:

1.A drip leg and a ground joint union must be installed in the gas piping.

2.When required by local codes, a manual shut-off valve may have to be installed outside of the unit.

3.Use wrought iron or steel pipe for all gas lines. Pipe dope should be applied sparingly to male threads only.

4.All piping should be cleaned of dirt and scale by ham- mering on the outside of the pipe and blowing out the loose dirt and scale. Before initial start-up, be sure that all of the gas lines external to the unit have been purged of air.

5.The gas supply should be a separate line and installed in accordance with all safety codes as prescribed under Limitations. After the gas connections have been com- pleted, open the main shut-off valve admitting normal gas pressure to the mains. Check all joints for leaks with soap solution or other material suitable for the purpose.

NEVER USE A FLAME.

6.The furnace and its individual manual shut-off valve must be disconnected from the gas supply piping system dur- ing any pressure testing of that system at test pressures in excess of 1/2 psig (3.48kPa).

The furnace must be isolated from the gas supply piping system by closing its individual manual shut-off valve during any pressure testing of the gas supply piping sys- tem at test pressures equal to or less than 1/2 psig (3.48kPa).

7.A 1/8 inch NPT plugged tapping, accessible for test gage connection, must be installed immediately upstream of the gas supply connection to the furnace.

8 Unitary Products