4 Common Hot Water Recirculation Pump Problems

A hot water recirculation pump has a number of benefits to any household, especially in times of limited water supply. These pumps provide instant hot water, reducing the wastage caused by letting water run until it comes hot from the tap. Millions of gallons of water is wasted every year from this problem.

A recirculation system is a hot water line that runs throughout the house and returns back to the water heater. It has a timer that turns on the pump at regular intervals, mostly during peak usage times. Here are 4 problems with these pump systems that you should be aware of. 

1. Power Waste

Because the pump is continually heating and circulating hot water through the pipes, it can use a lot of electricity. To combat this problem, all supply and return pipes must be well insulated to prevent heat loss. If you have a water heater that's far away from your kitchen and bathroom, and it takes a long time for hot water to reach the taps. If your water turns hot within 15 seconds after you turn on the tap, you will need to work out if a recirculating system is going to be cost efficient in your home. Insulating your pipes well will make a recirculating system energy efficient and reduce heat wastage. Making sure the pump is turned off late at night can help with some of the power waste. Even systems that use a temperature sensing unit that shuts off the pump when the water gets to a certain temperature don't help with the power usage, as the pump is not the main energy user; it's the heat loss that causes the pump to turn on.

Hot water on demand pumps are a better alternative if you are worried about power waste. 

2. Corrosion

Recirculation pumps are vulnerable to flow-accelerated corrosion, which can be a costly problem. This corrosion is caused by excessive flow velocity or aggressive water chemistry, and the pipes end up being eroded away by the water. The most affected areas are bends, elbows and tees where the walls of the pipe become so thin that they eventually rupture. The only fix for this problem is to change to a lower capacity pump and reduce abrupt changes in pipe directions. 

3. Noise Problems

Noise problems that happen after a power outage can be caused by air entering the system. The system is under pressure, which can cause a lot of noise. You will need to 'bleed' the system to allow the air to escape. Open the small air escape valve until water comes out, then repeat on all other valves. 

4. Low Flow Rate

Hot water recirculation pumps sometimes have a very small motor, which means that they can't produce much head pressure. This can impact badly on the flow rate. Many of these pumps can't even turn on a tankless heater. 

As long as you can reduce the heat loss through the pipes, a recirculating system can be a convenient and water saving feature for any home. Make sure your pipe insulation is mitred at the corners, so there is no heat escape anywhere along the lines.