4G. Combustion Condensate

Page 28

Figure 38. Collector Pressure Measurement

Correct any such problems and verify normal operation by returning to the venturi system checkout procedures.

Pressure readings will be less if the heater is located at an elevation significantly above sea level.

4F-3b. Flow in Heater and Vent

If the venturi inlet pressure reading is normal (or less than normal), flow may be blocked within the heater or in the exhaust venting, or the combustion blower may be operating below standard. To evaluate this, connect the negative side of the manometer to the collector pressure tap, as shown in Figure 38, leaving the positive side open to ambient (This requires a pressure tap with a 1/4" NPT thread). When the heater is operating, the pressure at this location should be about 3.5 ± 0.5" WC less than ambient for a model 220 and 2.8 ± 0.5" WC less than ambient for a model

350.If a greater reading is observed (i.e. more negative), flow is restricted within the heater, most likely at the burner or the heat exchanger. If the reading is substantially less (i.e. less negative), the combustion blower is not operating properly or flow is blocked after the blower, possibly in the vent. Correct any such problems and verify normal operation by returning to the venturi system checkout procedures.

Pressure readings will be less if the heater is located at an elevation significantly above sea level.

4F-4. Fuel Gas Type and Gas Orifice Size

The Hi-E2venturi combustion system requires only a gas orifice change to change from natural to propane gas or vice-versa. Required venturi system and gas pressures are the same for either gas. Required gas orifices are listed in the replacement parts list. Teledyne Laars configures its heaters for natural gas with 0.60 specific gravity and 1035 Btu/Ft3 or for propane gas with 1.52 specific gravity and 2500 Btu/ Ft3. Consult your Teledyne Laars representative if the available gas is substantially different.

4F-5. High Elevation Operation

The venturi combustion flow system completely compensates for installation at elevations other than sea level. Gas orifice changes are not necessary. Unlike conventional systems with open type burners and positive pressure regulators, the gas orifice differential pressure is created by the air flow, and it is automatically reduced when air density decreased. A Hi-E2 heater commissioned at sea level will operate at nearly the same air/gas mixture when operated at higher elevation. Its firing rate will decrease about 3% per 1000 feet due to the barometric pressure change.

In servicing a Hi-E2 heater at high elevation be aware that the input will be naturally reduced by this amount and that the differential pressures, as discussed in prior sections, will also be reduced. Pressure readings at various elevations will be approximately as follows:

Elevation		Gas Orifice	Unfired Venturi
Ft (m)		Differential	Differential
Sea Level 4.0" (102 mm) WC			4.7" (119 mm) WC
2000	(610)	3.7 (94)	4.3 (109)
4000	(1220)	3.4 (86)	4.0 (102)
6000 (1830		3.2 (81)	3.7 (94)
8000	(2440)	2.9 (74)	3.5 (89)
10000 (3050)		2.7 (69)	3.2 (81)

The gas pressure offset is determined by the regulator spring adjustment, not air density. It is not affected by elevation change.

The condensate disposal system of the Hi-E2pool heater is quite simple, but must be properly installed and maintained. See the installation instructions for information on correct tubing installation. Condensate drainage should be observed routinely and if necessary, the flow-ways should be cleaned.

In normal operation, condensate drains from the condensate collector behind the combustion fan. A 5/8" I.D. drain tube conducts this water into the condensate trap/neutralizer, where a “water seal” prevents room air from being pulled into the system. A smaller amount of condensate may drain from the vent duct and blower. The water seal of the trap prevents vent gases from being discharged into the room. See Figures 11 and 12 in the Condensate Disposal section of the installation instructions.

During start-up, condensate from the collector cannot reach the trap unless the water seal is established. This can be done by pouring water into the trap. The heater will self-prime by driving water into the vent outlet, from which it will eventually drain into the trap. However, it is better to avoid this by manually priming the trap.