Hot Water Recirculating Pump Installation: Mistakes to Avoid

A hot water unit equipped with a hot water recirculating pump will maintain a more consistent level of heated water to be used through their home. There are always dangers and mishaps that can occur when one is modifying a hot water system, so take precautions when installing your recirculating pump.

Safety Issues

Whenever you are working on a hot water system—whether it uses electricity or gas—there are always safety issues to consider. Make sure that in an electric water heater system that you not only shut off the hot water heater itself, but also shut off the breaker. In a gas water heater unit, the gas valve should be shut off both at the water heater and at the supply line. There should be no sparks or open flames around the hot water heater even if the gas is turned off.

Avoid wearing loose clothing while you work.

Running Pipes and Tubes

Just like hot air, hot water rises. When running the pipes for your recirculating pump be sure that the return pipes are lower than the hot water feed pumps. If you run the cool return water above the hot water then the recirculation will not occur properly in the system.


When installing the recirculating pump in your hot water system you do not have to consider insulating. The pump system works much better without insulation. The problem with this, though, is that if it is not insulated then the water heater will cycle between on and off more often. This occurs because the hot water that would normally be insulated in the hot water tank is instead in the tubes where there is no insulation to retain the heat. Circulating the water out of the tank causes more cool water to come in and forces the thermocouple to activate the pilot or sensor to turn on the elements. Because of this, you must ensure that the hot water lines coming from the water heater are insulated to help the process from working more efficiently.

Air Locks

Be very careful that you do not create air pockets in your water lines. If you put air in your lines then your pipes will begin to hum and rattle. You can bleed the system of air by opening a valve, much like bleeding brakes on a car, and allowing water to push the air out of the system. Air can actually block the water flow through your recirculation loop. Because the recirculation relies on gravity and not water pressure the air pocket will not move. Water flows very slowly through a system that uses gravity to function.


Make sure that the system is installed with a check valve to enable the water to flow in a single direction. If this valve is not installed there can be a confusion in the direction that the water flows causing problems with circulation.