Riverside Hydronics EMX SERIES Installation & Maintenance Manual - page 14
EMX, EMXO and EMXGO SERIES WATER BOILERS
34-503 07/13
14
2. Oil supply and return lines must be installed below frost level. Below-floor-level runs are preferred inside
the building. Avoid overhead runs, which can cause excess lift for the oil pump. Return lines must be as
large as the supply lines with no shutoff valves in the line. If a shutoff valve is installed in existing return
line piping, remove or open and disable it to prevent accidental closure.
IMPORTANT: A supply line filter must be installed and cleaned or replaced regularly.
3. 90% of all oil pump problems resulting in poor cutoff, noisy operation and erratic firing are caused by air
vacuum leaks in the supply (suction) line. To avoid air leaks, both return and supply lines should extend
to near bottom of the oil tank. Only flare type fittings should be used, and all fittings and joints must be
tight. Check and recheck all fittings and joints for air vacuum leaks.
4. Supply line size is based on the suction developed from the total "gear capacity" of the pump. The pump
is a positive displacement type and pumps a constant volume of oil, only a portion of which is used by the
nozzle(s), the remainder being bypassed to the return line. During gas operation on the combination
gas/oil burner, the pump is operational, but all oil is bypassed to the return line.
5.
No allowance has been made in the recommended supply lines sizes (see Table 2) for additional severe
restrictions such as multiple elbows, etc. If in doubt of the size required, use the next size larger than
recommended. The oil lines (especially the supply line) must be absolutely leak tight to prevent loss of
prime. Do not use Teflon tape or oil soluble pipe dope.
CAUTION: If the "lift" from the oil tank to the pump inlet is over 12 feet or if the "lift" plus the supply
line pressure drop is such that the total suction at the pump exceeds 15" mercury, install a booster
pump. Pressure at the burner inlet must not exceed 3 psi.
RECOMMENDED OIL SUPPLY & RETURN LINES
LIFT
ABOVE
TANK
COPPER TUBING SIZE
(OD)
LENGTH OF RUN
IRON PIPE SIZE
LENGTH OF RUN
50' 100' 200' 50' 100' 200'
0 feet
1/2" 1/2" 5/8" 3/8" 3/8" 1/2"
5 feet
1/2" 1/2" 5/8" 3/8" 3/8" 1/2"
8 feet
1/2" 1/2" 5/8" 3/8" 3/8" 1/2"
12 feet
1/2" 5/8" 5/8" 3/8" 1/2" 1/2"
TABLE 2
FIGURE 3