Weil-McLain 550-141-850/0599 manual Annual start-up— check/test, Expansion tank, Gauges, Igniter

•Installation • Start-Up • Parts • Maintenance

Annual start-up — check/test

Part number 550-141-850/0699

Expansion tank

1.Expansion tanks provide space for water to move in and out as the heating system water expands due to temperature increase or contracts as the water cools. Tanks may be open-, closed- or diaphragm- or bladder-type. See Section III of this manual for suggested best location of expansion tanks and air eliminators.

Open-type— Located above highest radiator or baseboard unit, usually in the attic or closet. Has a gauge glass and overflow pipe to a drain.

Closed-type— Welded gas tight and located above boiler. Tank is partially filled with water, leaving an air cushion for expansion.

•Make sure this type of tank is fitted with a tank fitting, such as the B & G Tank-Trolor Taco Taco-Trol. This fitting reduces gravity circulation of air-saturated tank water back to the system and prevents the air from bubbling up through the water as it returns from the system.

•Do not use automatic air vents in systems with closed-type tanks. The air will escape from the system instead of returning to the tank. Eventually, the tank will waterlog and no longer control pressurization. The boiler relief valve will weep frequently.

Diaphragm- or bladder- type — Welded gas tight with a rubber membrane to separate the tank pressurizing air and the water. May be located at any point in the system, but most often found near the boiler.

•Systems with this type of expansion tank require at least one automatic air vent, preferably located on top of an air eliminator, as shown in examples in manual Section III.

2.If relief valve has tended to weep frequently, the expansion tank may be waterlogged or undersized.

Closed-type tank — Tank is most likely waterlogged. Install a tank fitting if not already installed. Then check fill level per fitting manufacturer’s instructions. If fill level is correct, check tank size against manufacturer’s instructions. Replace with a larger tank if necessary.

Diaphragm- or bladder type — First, check tank size to be sure it is large enough for the system. If size is too small, add additional tank(s) as necessary to provide sufficient expansion. If tank size is large enough, remove tank from system and check charge pressure (usually 12 psig for residential applications). If tank won’t hold pressure, membrane has been damaged. Replace tank.

Gauges Figure 29 Igniter observation port in blower

1.Boiler pressure/temperature gauge — Inspect gauge and check

whether readings are reasonable. Replace if any signs of leakage from case or improper readings.

2.System gauges (if installed) — Inspect and check readings of other gauges in system.

Igniter

1. Verify igniter operation — Look
through blower observation port
(see Figure 29). Access the blower	Observation port	85034

by removing the boiler jacket front panel if not already removed.

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