Gas Pressure Setting Verification - Pentair ULTRATEMP ETi Installation Manual

8

Gas Pressure Setting Verification

After completing Conversion Instructions (see pages 6-7), follow the steps below to
verify the gas supply pressure:
replace it with an orifice of a different size.
1. Ensure power to the heater has been disconnected at the circuit breaker
and the pump is turned off.
2. Close the manual gas supply valve to the heater.
3. Using a 3/16" Allen wrench, remove the plug from the 'PRESSURE TAP' port on
the outlet side of the Gas Control Valve (GCV). Set aside the plug.
4. Install a 1/8" NPT barbed fitting into the 'PRESSURE TAP' port on the outlet side
of the GCV.
5. Connect the low side of a differential pressure gauge or a slope gauge to the
barbed fitting using a flexible tube. This gauge will measure low (outlet) pressure,
which requires a high degree of resolution.
6. Open the manual gas supply valve to the heater and turn the GCV toggle switch
to the ON position.
7. BEFORE OPERATING THE HEATER, LEAK-TEST THE HEATER AND ALL
ITS GAS CONNECTIONS WITH SOAPY WATER!
8. Return power to the heater at the circuit breaker and turn on the pump.
9. Start the heater.
Note: If you are using a slope gauge, close the shutoff valve of the gauge
to avoid pulling the liquid out of the gauge when the blower starts.
10. After the burner lights, verify that the supply pressure is within the range 4" to
14" wc. If the supply pressure drops below this range when the burner ignites,
the gas line capacity may be inadequate, and should be increased.
11. With the burner still on, disconnect the plastic tube between the GCV 'VENT' tap
and the blower mixer inlet. The pressure gauge should then read -0.2" ±0.1" wc.
If the pressure is outside the range listed, call the factory at 1-800-831-7133. DO
NOT attempt to adjust the pressure yourself.
12. If the pressure is within the limits given in step 11, the gas pressure is at the
optimum level. Reconnect the plastic tube between the GCV 'VENT' port and
blower mixer inlet.
13. Remove the 1/8" NPT barbed fitting from the 'PRESSURE TAP' port and reinstall
the plug. Be sure it is tightened properly.
14. Run the heater for at least 10 minutes, then insert a combustion analyzer probe
into the exhaust and
measure flue gas levels.
Recommended flue gas
levels are listed in Table
1. Preferably, the readings
should be in the midrange.
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Fire and explosion hazard. The Air Orifice is sized specifically for the
air/gas mixture required by the burner. Do not modify the Air Orifice or
Risk of fire or explosion. Never test for gas leaks with an open
flame.
Table 1. Recommended Flue Gas Levels
Natural Gas
CO
Fuel
(Dry Basis)
Propane 9.7 - 10.3%
7.8 - 9.2%
2
O
2
5.7 - 6.3%
4.8 - 7.2%
CO
150 Max.