750-297
Profire E/LNE Series Manual
2-11
Installation
2.8 — Circulating Oil Pump
A circulating oil pump is required to deliver fuel oil from the storage tank to the burner at a minimum of 150% of
the maximum burner firing rate. The excess oil allows a margin for piping error, viscosity changes in the fuel oil,
and circulating pump wear. Correct pipe sizing is determined by circulating rate, not burner capacity. Install the
pump as close to the supply tanks as possible. Suction lift should be as low as possible. Maximum suction of 15"
Hg vacuum is good practice for either light or heated heavy oil. The strainer should be installed in the suction line
just ahead of the circulating pump to prevent foreign material from entering the pump. Locate the strainer so it
may be easily cleaned.
2.9 — Back Pressure Valve
A back pressure valve, similar to Watson McDaniel type "R," needs to be installed on the return line. This valve
must be installed in an upright vertical position. Before installing the valve, be sure to blow out the pipe line,
removing all dirt, pipe scale and sediment. This type of valve is actuated by the system pressure which enters the
body beneath the main valve. Valve loading is provided by a spring that can be adjusted to the desired set
pressure.
To adjust the set pressure, remove the top cap, loosen the brass locknut and adjust the pressure with the steel
setscrew. By increasing the compression on the spring, screwing down the screw, you increase the set pressure
within the limits of the spring range. Reversing the setscrew lowers the set pressure.
Adjust to 10-15 PSI for No.2 oil systems. When the desired pressure is reached, tighten the locknut and replace
the top cap and gasket.
2.10 — Gas Piping
Refer to Figures 1-4 and 1-5 for typical gas train piping.
Gas service and house piping must supply the quantity of gas demanded by the unit at the pressure required at
the burner gas train inlet. All piping must be in strict accordance with applicable codes, ordinances, and
regulations of the supplying utility. In the absence of other codes, piping should be in accordance with the
following standards: "National Fuel Gas Code" NFPA No. 54, ANSI No. Z 223.1 (for Canada, the Canadian Gas
Association (CGA) B149 and Canadian Standards Association (CSA) B140 codes shall prevail).
Gas train components upstream of the butterfly valve are shipped loose. These components should be mounted
by the installer as close to the butterfly valve as practical. Normally, the control train is ordered to suit a
particular code or insurance regulation, such as Underwriters Laboratories Inc., CGA, or Factory Mutual.
Arrange gas piping at the burner so that the burner is accessible for servicing without disassembly.
The gas pilot supply line must be connected upstream of the main gas regulator. If a reducing bushing is required
between the house piping and the burner piping, it should be close to the burner shut-off valve.
The gas piping must be internally clean and free of foreign material. Before using in service, a leak test must be
performed.
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