Operator`s manual

PUREHEAT™ HYDRONIC AIR HEATER OPERATOR’S MANUAL – SECTION 3
3- 2 © 2006 Ground Heaters, Inc. V. 2, Rev. 09/01/06
3.1.1.1 Fuel Pressure Adjustment
1. Ensure that the fuel supply source is OFF.
2. Ensure that the Main Gas Supply Ball Valve is SHUT.
3. Remove the ¼ in. pressure tap plug located in the gas train inlet ball valve body (opposite of the pilot
gas cock).
4. Install a ¼ in. petcock and pipe adapter in the location of the pipe plug to facilitate connecting the 0 to
30 in. WC Manometer. Ensure the petcock is SHUT. Do
not use pipe dope on this joint.
5. Remove the ¼ in. pressure tap plug located at the end of the “T” fitting just below the gas train union.
6. Install an adapter in the location of the pipe plug to facilitate connecting the 0 to 15 in. WC
Manometer for manifold pressure adjustment. Ensure the petcock is SHUT. Do
not use pipe dope
on
this joint.
7. Loosen the air dampers locking screws enough to provide movement for adjustment. Open the top
damper 45% and fully shut the bottom damper. (Refer to Appendix A-24)
8. Turn on the main gas supply.
9. Crack open the installed petcock of the supply line slowly
while continuously monitoring gas pressure.
Immediately shut the petcock if the gas pressure climbs past 14 in. WC. Contact your fuel supplier
for gas pressure adjustment of no more than 12 to 14 in. WC before proceeding with further
adjustment.
10. Once a maximum gas supply pressure of 12 to 14 in. WC has been verified; open the Main Gas
Supply Ball Valve.
11. Remove the protective cap from the Manifold Gas Pressure Regulator to access the regulator
adjusting stem.
12. Using a screwdriver, adjust the Manifold Gas Pressure Regulator stem until it is no more than ¼ in.
below the threaded opening if using LP or no more than ½ in. below the threaded opening if using
NG. This will avoid over-firing upon initial start up.
13. Open the gas manifold valve.
14. Turn MAIN BREAKER 1 and MAIN BREAKER 2 Switches ON. Allow a 15 second time delay for the
low heat transfer fluid (HTF) system to recycle and clear.
15. Ensure that the digital temperature control’s green numbers (temperature set-point) are at least 10º to
20ºF (5º to 11ºC) degrees higher than the red numbers (actual HTF temperature).
16. Turn the BURNER Switch ON.
17. After a 15 second pre-purge, the Burner will begin the ignition sequence; the pilot gas valve will open
followed 15 seconds later by the main gas valves (MGV’s).
18. Once the MGV’s open, monitor the manometer connected to the manifold pressure tap and adjust the
manifold regulator stem until the following values are obtained: 1.6
to 2.0 in. WC (LP);
2.5
to 3.0 in. WC (NG).
NOTE: Turn the manifold regulator stem clockwise to increase manifold pressure; turn the stem
counterclockwise to reduce the manifold pressure.
19. Once the appropriate fuel pressure is set, proceed with air setting and adjustment.
3.1.1.2 Air Setting and Adjustment
Top or bottom air dampers may be opened or closed in amounts sufficient to adjust exhaust 0
2
levels to 3
to 5% using a combustion analyzer.