To avoid water damage or scalding from operation of the relief valve, install a drain pipe in the outlet of the pressure relief valve that will direct water discharging from the
To High Side of Differential Pressure Gauge
valve to a safe place for disposal. Do not install any reduc- ing couplings or valves in the drain pipe. The drain pipe must be installed so as to allow complete drainage from the valve and drain line. The relief valve should be tested at least once a year by lifting the valve lever.
Explosion hazard. Any heater installed with restrictive devices in the piping system downstream from the heater (including check valves, isolation valves, flow nozzles, or therapeutic pool valving) must have a relief valve installed as described above. See Page 16.
ON
CAUTION
PILOT
VENT
PRESS |
TAP
Connection for |
|
Test |
|
To Low Side of Diff. |
|
Pressure Gauge |
|
| To Air Flow |
| Switch |
| NOTICE: The gas |
| piping and unions |
| are not shown |
Connection for | for clarity; make |
this test with all | |
Service | gas piping |
| connected (as for |
| normal service). |
2788 0397
FIGURE 21: Connect Gas Valve to End Cap Air Orifice
Instructions For Checking the Gas Pressure
Through the Combination Gas Control Valve
Risk of fire and explosion. Improper installation, adjustment, alteration, service, or main- tenance of the Combination Gas Control Valve can lead to fire or explosion, causing loss of life, per- sonal injury, or property damage.
These instructions are for the use of qualified service technicians only!
Do not attempt this procedure unless you have been trained and certified in the care and repair of
Do not attempt this procedure if the following instructions are confusing!
This appliance is equipped with an unconventional gas control valve that is factory set with a manifold pressure of
The combination gas valve incorporates dual
Do not attempt to adjust the gas input by adjusting the regulator setting. The correct gas regulator setting is required to maintain proper combustion and must not be altered.
To check that the gas pressure setting is correct, use the following procedure:
1.Turn off the heater and remove the top covers for access to the Combination Gas Control Valve.
2.Use a 3/16” hex key to remove the plug from the ‘PRESSURE TAP’ port on the outlet side of the
Combination Gas Control Valve.
3.Install a 1/8” NPT barbed fitting into the ‘PRESSURE TAP’ port. Use a flexible tube to connect it to the low side of a differential pressure gauge or a slope gauge.
NOTICE: If you are using a slope gauge or a differ- ential pressure gauge of less than 3” capacity, close the shutoff valve of the gauge to avoid pulling the liq- uid out of the gauge when the blower starts.
4.Disconnect the tube from the Gas Valve ‘VENT’ port. Connect it to a tube with a tee running to the high side of a differential pressure gauge and to the blow- er’s air orifice grille (See Figure 21, above).
5.Turn on the heater and verify the gas supply pres- sure (Page 20).
6.After the burner ignites, open the shutoff valve of the gauge. The pressure gauge should then read 0.2” wc ±0.1” wc (0.0” to 0.1” wc = rich mixture; 0.3” to 0.5” wc = lean mixture). (Since the pressure tap is con- nected to the low side of the gauge, the pressure is actually negative.)
Risk of fire or explosion if Combination Gas Control Valve is incorrectly adjusted. If it is necessary to adjust the gas valve, this must be done only by a qualified service agency.
7.Turn off the heater.
8.Replace the plastic hose between the ‘VENT’ port and the inlet of blower mixer. Remove the barbed fit- ting and replace the plug in the ‘PRESSURE TAP’ port of the gas valve, using a thread sealant approved for use with natural gas and LPG.
9.Replace the heater covers and cycle the heater to check for proper operation.
19