COMFORT Mechanical installation

Discover how to install COMFORT pumps in hot water recirculation systems located within residential buildings.

In this video, you will learn how to install COMFORT pumps in hot water recirculation systems located within residential buildings. Before installing the pump, take time to read the installation instructions carefully. These can be found via the QR code on the pump display.
First, ensure that the non-return valve and the shut-off valve are present in the system. If your system is branched, make sure it is fitted with balancing valves and it is hydraulicly balanced. When choosing the place for pump installation, note that the COMFORT pumps with temperature control must be mounted on the return pipe at least 50cm away from the boiler.

For AUTOADAPT pump variants with external temperature sensors, you'll find the sensor and sensor cable attached to the control box cover. You must not pull on the sensor cable - this risks causing damage. Gently unwind the sensor cable to the desired length by rotating the control box counterclockwise. Strap the sensor on a clean, straight part of the supply pipe, avoiding tee joints or insulation.

The optimal distance from the boiler to the sensor is 20cm for composite pipes and 50cm for metal pipes.
For AUTOADAPT variants, it is recommended that the water heater temperature be set to more than 48 degrees Celsius or 120 degrees Fahrenheit.
COMFORT pump housings are available in three sizes, subject to availability in certain countries. The two bigger housings come with shut-off and non-return valves.

If the system is pressurised, ensure the area in which you install the pump is isolated. Beware of the hot water inside the pump. The arrow on the housing indicates the direction of water flow through the pump. If valves were supplied with the pump, make sure to screw the shut-off valve upstream of the flow and the non-return valve downstream of the flow. Fit the gaskets supplied with the pump when you mount the pump in the pipe. Tighten the fittings and then place the insulation shells on the pump housing to reduce heat loss.

COMFORT pumps can be mounted vertically, horizontally, and with the pump head pointing down. However you mount the pump, make sure the cable faces downwards after installation. You cannot mount the pump with the pump head pointing up.

If you need to rotate the pump display, loosen the union nut and rotate the pump head to the desired position. Then tighten the nut to secure it again.
When replacing an old pump, you may only need to replace the pump head. Due to the impeller design, it fits the brass housing of many other pump brands. If the system isn't fitted with a venting valve, you may need to flush the system via the pump housing. The system needs to be free of air to properly function. To isolate the system, you close the shut-off valve and then dismount the pump head. Grundfos provides venting flanges as an optional accessory. Screw the venting flange onto the pump housing and mount a hose on the flange. Then open the shut-off valve upstream from the pump and allow water to escape until the pipes are free of air. When done, close the valve again, remove the flange, and remount the pump head.

Finally, connect the COMFORT pump to the power supply. Note that a cable with a plug is included in all models, except for Great Britain where users need to buy the cable separately. The included plug can then be easily connected to the cable with a few simple steps.

Switch the pump on and vent any remaining air. This can be done by switching the pump on and off several times. Another option is to open and close the hot water tap furthest away from the pump, repeating the process five to six times until the pump runs quietly.
That covers the installation of the COMFORT pump.

Course overview

Modules: 5
Completion time
Completion time: 25 minutes
Difficulty level
Difficulty level: Intermediate