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How To Replace A Circulator Pump On A Boiler

The circulator pump acts like a human heart in a hot water boiler heating system. The pump moves hot water from the boiler up through pipes and into the radiators and baseboards used to heat your home. The pressure from the pump then forces the water from the radiators and baseboards back into pipes that lead back to the boiler where the water gets reheated again before it starts its journey back up through the heating system. If the pump breaks, you'll need to replace it to get your heating system working again. Here is how to replace a circulator pump used in a hot water boiler system.

Step One: Drain Pipe

Turn off the boiler and shut off the water valve going to the boiler. Allow the hot water to cool down in the pipes and boiler. Then open the drain valves at the bottom of the pipe below the circulatory pump.

This valve will look like a hose spigot in most cases. You can attach a hose to the valve to direct the water into a floor drain.

Step Two: Disconnect Electric

Turn off the circuit breaker at the circuit panel, or if you have fuses, take out the fuse leading to the boiler. Open the cover to the electrical wiring on the side of the pump and disconnect the electrical wires.

Step Three: Remove Bolts

The circulator pump is bolted to two brackets on the pipe leading away from the boiler to the radiators in your home. One bracket is on top of the pump and the other bracket is at the bottom of the pump.

Unbolt the brackets and slide the pump out from between the pipe.

If the bolts are rusted to the brackets, put a grinding wheel on a drill and saw the bolts off the brackets.

Step Four: Install New Pump

Slide the new pump into position between the pipe brackets where the old one was located. Make sure you use new gaskets to seal the connection between the pump and the brackets on the pipe. Bolt the pump into position.

Reconnect the wires to the new pump and restore the electricity.

Step Five: Bleed Air from Pipe

Air in the system will cause loud knocking in the heating system and could also damage the new pump. Shut the drain valve off and open the water valve to fill the pipe back up with water. The bleed valve is usually located either on a low elbow on the pipe going to the boiler, or midway up on the pipe going to the boiler.

Open the bleed valve to allow the water to force the air out of the pipes. You know the air has been forced out once water starts running through the bleed valve. Close the bleed valve.

Step Six: Turn on Boiler

Turn the boiler system back on and wait until it heats up. Check to make sure hot water or steam doesn't leak between the connections between the pump and the brackets on the pipes. To learn more, speak with a business like Robinson Heating & Cooling Inc.


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