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How to Install a Hot Water Recirculating System

If you are like me, having hot showers every morning is a must. Therefore, having a recirculating system is essential. 

These systems are efficient and offer value for money. Unfortunately, they are a bit expensive. You can save a ton of money if you install it yourself.

How to Install a Hot Water Recirculating System 1

Installing a Recirculating Hot Pump Without a Technician

Professional plumbers can help with this pump installation. However, hiring a licensed and registered plumber will cost you up to $800. Fortunately, you can install it yourself.

If the piping system is not easy to remove, then only proceed with the support of a professional plumber. This happens with a CPVC piping system.

Note that the typical hot water recirculation pumps are for above-water installation. The few that work under the sink installation have in-built sensor valves as part of the pump. Now that you understand this type of pump, proceeds with the installation.

Step 1 – Turning Off the Gas Valve and Water Heater Breaker

How to Install a Hot Water Recirculating System 2

Turn off the power to the water heater. Find the breaker at the electrical panel and proceed to flip the switch. Turn the water heater power and the gas off if the system is not fully electric. 

Find a yellow or red gas valve near the water heater. Alternatively, follow the water heater’s gas line. Shut the gas line off by turning the valve perpendicularly. Note that old water heaters will have a pilot light. Make sure this pilot light extinguishes completely.

Step 2 – Shut the Water Water Heater Off

Turn the water off at this stage. Use the valve directly above the water heater, or close by. Turn the valve perpendicularly to shut off the water.

If unsure about the valve or are unable to shut it off, shut the main valve. Unfortunately, this will shut down the water supply for the entire house.

Step 3 – Draining Hot Water from all Fixtures

How to Install a Hot Water Recirculating System 3

Once the water supply shuts, flush or drain the hot water from the pipes. Find the lowest fixture in your home and open the hot water. Allow all the hot water to drain. 

This shouldn’t be continuous. If the hot water flows non-stop, then there is a possibility that water still runs through the system.

Step 4 – Draining the Water Heater

After draining the hot water from the pipes, drain more water from the heater. Check for the heater’s drain valves at the pump’s bottom. Connect a hose to this valve and use a flat-head screwdriver to open the valve. 

I advise draining the water to the nearby utility sink. Complete by closing the utility valve using the same screwdriver.

Step 5 – Removing the Hot Water Pipe from the Water Heater

After draining all the hot water from the pipe and heater, drain the outlet pipe. It is easier if the pump comes with easy-to-remove braided flex piping. Use a pipe wrench to loosen the nut from the 3/4″ flex pipe connection and remove the pipe.

Consider hiring a plumber when dealing with PEX, copper, or CPVC pipes. These need cutting and soldering, which a plumber handles best.

Step 6 – Connecting the Pump and Threaded Nipple

Install the hot water pump to the outlet’s threaded nipple. This is after removing the hot water discharging pipe. Ensure that the water pump installation is perfect. The arrow on the housing must point to the water flow direction and away from the heater.

Note that you do not need Teflon plumbing tape if there is a rubber gasket on the female threaded nipple.

Step 7 – Connecting the Hot Water Supply Line to the Pump

At this, you have already connected the recirculating hot pump. Therefore, connect the hot water line to the pump’s outlet nipple.

This requires that you tighten the ¾” nut using a wrench. If the flex piping female end lacks a rubber gasket, install Teflon tape. This reinforces and guarantees a leak-free situation.

Step 8 – Turning on the Water

It is now safe to turn on the water-to-water heater. Once it fills up, consider running a plumbing fixture unit till all air from the pipe ends. Target all the home’s piping systems for this.

Step 9 – Find the sink that is Farthest from the Circulation Pump

After installing the recirculation pump, find the sink farthest from the water heater. Install the sensor valve here. Find the sink that receives hot water last if you are unsure which sink is the farthest.

Step 10 – Shutting Off the Sink’s Stop Valve

This involves shutting off the water to this sink. Look for hot water and cold water shut valves. These valves are under the sink. Turn the valve perpendicularly by pushing or pulling it down to shut them off.

Step 11 – Remove then Connect Flex Lines to the Sensor Valves

Remove the flex lines from the stop valve directly. The ends of the flex line are either 1/2″ or 3/8″. The sensor valve only has ½” connections, though.

Consider buying flex pipes with the following measurements, 1/2″ to 3/8″ ends — 1/2″ to 1/2″ ends — or 3/8″ to 3/8″.

You can buy flex pipes with 1/2″ to 3/8″ ends, 1/2″ to 1/2″ ends, or 3/8″ to 3/8″. Alternatively, get the 1/2″ to 3/8″ adapter fittings, not new hoses.

Connect the supply water lines to the cold & hot water outlets at the sensor valve top. Then connect new flex lines from the stop valves to the sensor valve sides.

Step 12 – Installing more than a Sensor Valve

This applies to larger houses that need many/ branched piping. Consider installing an extra sensor valve at a different location. Add sensor valves under the same sink (parallel). It reduces low temperatures and increases the water flow.


Is a hot water recirculating system worth it?

Yes, it is. Despite the high initial cost, the investment is worth it in the long run.

Does a recirculating pump need a return line?

Not all pumps need this.

How long do hot water recirculating pumps last?

They can last for over a decade with proper maintenance.