Introduction
The problem: The radiators, underfloor heating or hot water remain cold even though the heat source is working.
Especially if the heating circulating pump was not in operation over the summer, it may be that the first start afterwards does not work. As a preventive measure, you could run the pump for a few seconds once a month, even in the summer. But if you're reading this guide, it's probably already too late for that this time. However, the problem can also appear at any time for no apparent reason.
The first attempt, which is then usually made, can also be found in many other places on the Internet, including in several videos. If these tips don't help, you don't have to throw the pump away right away, you can give it a second chance with these instructions. Especially when the problem (like mine) occurs on a Sunday morning and you can't buy a replacement pump without calling emergency services
The first 3 steps are easy. You have to decide for yourself whether you trust yourself to do the rest of the steps. I have written this manual to the best of my knowledge and belief. Nevertheless, I decline all responsibility if something goes wrong with your fix when copying.
Before you get started, please check whether the ownership situation and regulations at your place of residence allow you to carry out work on the heating system. In any case, you are responsible.
-
-
Before beginning the following steps, make sure the pump is running. Because if it does work, then these instructions are not suitable for your problem. Only step 11 would still have to be checked.
-
If you're familiar with the usual, low operating noise of the pump and it has now become a very low, low-pitched hum or no noise at all, then the pump rotor may be stuck. The hum is consistent with (e.g. 50 or 60 Hz) and clearly not regular running noise.
-
Caution: The pump may be hot. Please check before you touch the pump with your ear. It is safer, for example, to hold a screwdriver with one end against the bleed screw of the pump (red arrow) and with the other end against your ear. This way you can listen to the pump like a doctor with a stethoscope.
-
If you can't identify a running noise (or if you're not sure), then you've come to the right place.
-
Note: With some pump types, the vent screw (marked red in the picture) is covered by an additional housing. I don't own such a pump so I can't offer a solution for it. It may be possible to easily remove this additional housing.
-
-
-
Open the pump's large bleed screw with a suitable, large slotted screwdriver. You can also use a coin if you don't have a large enough screwdriver.
-
Warning: Some water will run out. Hold some sort of catch container under the pump.
-
The face of the rotor shaft is now visible. Depending on the type of pump, there is a notch, either in the form of a slot or a cross.
-
If you are unsure if the pump is running, carefully insert a screwdriver (e.g. 5mm slot) into the hole and be prepared that it will start to turn by itself if the pump is running. In this case, the instructions end here. Reinstall the bleed screw. Ensure that there is no water dripping .
-
If the pump runs slowly and does not react to the change of the power levels with an audible change in speed, you could finally go to step 11.
-
-
-
Select a screwdriver that is sized and shaped to match the indentation in your pump. Insert the screwdriver into the opening exposed in the previous step.
-
Try turning the pump rotor using the screwdriver. If that works, turn on the pump. Does it start on its own? Good, problem solved.
-
If it doesn't start on its own, give it a little jump-start by quickly turning the screwdriver in the direction indicated by the arrows on the case and "starting" the pump.
-
Michael B wrote to me: There is a notch on his circulation pump. Insert the screwdriver into this notch and then hit it with a small hammer in the direction of rotation (indicated on the pump) so that the flywheel starts to move.
-
Does the pump now run? Then the problem is solved. Reinstall the bleed screw and check that no water is dripping out. Ready.
-
Otherwise, if the pump is still not working:
-
Did the rotor turn easily during startup? Continue to step 11
-
If it was difficult or even impossible to turn the rotor, continue with the next step.
-
-
-
Shut off the water supply on both sides of the pump. If you are lucky, any necessary maintenance was already considered when the pump was installed. There might be a ball valve directly in each flange that connects the pump to the rest of the pipe network. All you have to do is turn its slot 90° with a screwdriver.
-
Otherwise you will have to look for suitable shut-off options in your facility.
-
-
-
-
Depending on the type of pump, it is connected with either one or two cables. If these are plug connections, then carefully loosen them. The plugs usually have a mechanical lock that you have to lift slightly with a small screwdriver beforehand.
-
If the electrical wiring is permanently connected to the pump, then the usual safety precautions necessary for all electrical work must be taken. Switch off all poles and all sides, etc., check that there is no voltage!''
-
Warning: if you are not familiar with these things and unsure on how to proceed please stop your work at this point. Otherwise you would endanger your own safety and maybe other people too! Before continuing into an area that could cause harm, ask someone who has the relevant specialist training for help.
-
-
-
Make a note of the installation direction of the pump, i.e. the direction in which it pumps the water. You'll find an arrow in the middle of the pump, between the pipe connectors (red rectangle).
-
Now open the screw connection on one side of the pump a little. There will be water coming out so use a catch container (bucket etc,) to capture that.
-
If the water leakage does not subside after a very short time and stops completely, then you have probably not completely shut off the water supply. Should that happen, retighten the fitting immediately.
-
Open the screw connection on the second side of the pump.
-
Remove the pump. Be sure to keep the gaskets you find on both sides.
-
-
-
Caution: If you continue now, you will probably void any warranty for your pump.
-
Loosen the four assembly screws with a suitable Allen wrench
-
Now pull the two housing parts apart. Make a note of the original position of the two parts in relation to each other so that you can put them back together exactly the same way later. If you were to assemble them incorrectly, e.g. rotated by 90° or 180°, you would probably have problems installing them in your system.
-
The pump impeller should now be visible. Try to turn it carefully. If this works fine and easily after a few changes of direction, you can put everything back together and skip to the last step.
-
However, if the impeller (as in my case) is completely stuck and cannot be turned at all, then the next step is carried out.
-
-
-
I suspected a lime deposit and was able to successfully dissolve it with commercially available vinegar essence. In detail ...
-
Place the pump, impeller down, on a small plastic container, such as a small bucket.
-
Pour a few drops of vinegar essence into the opening marked with the arrow until the essence drips out at the bottom. If you don't have vinegar essence at hand, you can also use normal salad vinegar. The process just takes longer.
-
Note the safety instructions on the essence bottle. If nothing is written there, use rubber gloves and safety goggles. If you have accidentally worked without gloves, rinse your hands with clear water to be on the safe side.
-
Wait 15 to 30 minutes
-
Then try to spin the wheel. If it still doesn't turn or doesn't turn easily, repeat the above process. My pump was fine after three repeats.
-
Now let water run through the pump - even through the opening marked by the arrow, to flush out any acid residue. You can dispose of the now heavily diluted acetic acid down the drain without hesitation. It is in principle a food and is now certainly much weaker than your salad dressing.
-
-
-
Before assembling, make sure that the gasket between the two housing parts is clean.
-
Put the two housing parts back together. Pay attention to the alignment of the two parts to each other as noted earlier.
-
Insert the four Allen screws and tighten them "crosswise" evenly (i.e.: top left, bottom right, bottom left, top right) - only tighten slightly at first and then tighten completely in a second round
-
-
-
Now put the pump back in its old place. Note the previously noted direction of conveyance. Don't forget to put the two gaskets (cleaned) between the flange and the pump.
-
Reinstall the bleed screw and tighten it.
-
Open the first water shutoff a little. Be ready to snap it back on immediately in case you didn't mount the pump properly or tightly. If necessary, tighten the screw connections.
-
Now open any other shut-offs that you previously closed. Check for any leaks.
-
Reconnect the electrical connections
-
Time for a test run!
-
If there is an automatic bleed valve somewhere above the pump, the job is done. Otherwise, you'll probably need to bleed the radiators now.
-
Check the water pressure in your system according to the specifications of your system.
-
-
-
If your pump is equipped with a capacitor, you will usually find a corresponding inscription on the nameplate of the pump. In the example pictures, "3 µF" at the bottom right and "2.5 µF" at the center left.
-
If the pump runs very slowly and hardly delivers any water, then it is worth checking the condenser. Likewise, if the pump does not respond to the power stage changeover with an audible change in speed. Or if it does not run at all, although the pump impeller can be turned easily.
-
Please perform this step only if you have the appropriate electrical engineering expertise. Otherwise, ask someone for help. See step 5.
-
Switch off all the poles and all the circuits. Check that no voltage is present.
-
Disconnect the capacitor and measure its capacitance. If it is much lower than the value printed on the capacitor and on the nameplate, then this could be a reason for the behavior described above. I once found a capacitor that had only 66% of the printed capacity. Capacitor replaced - pump fine.
-
See also Ralf Müller's comment under step 10.
-
-
-
If everything is working again, you could now think about or even check if your heating can be set to be more energy-efficient without losing living comfort.
-
For example: Is your circulation pump constantly running at high power 24 hours a day and therefore consuming an unnecessary amount of electricity? Or does the heating control system ensure that it only runs when necessary and also controls the pump's output depending on the heating situation?
-
Is the heating control system unable to do this? Then the installation of a so-called high-efficiency pump, which automatically adapts to the heat demand, could greatly reduce electricity consumption.
-
There are many articles on energy-saving topics on the Internet. These lines are only intended as an invitation to do your own research.
-
For pumps without slide valves upstream and downstream of the pump, the water of the entire heating circuit must be drained. The heating circuit must then be refilled and vented if necessary. After 24 hours, check again whether everything is tight and bleed again.
For pumps without slide valves upstream and downstream of the pump, the water of the entire heating circuit must be drained. The heating circuit must then be refilled and vented if necessary. After 24 hours, check again whether everything is tight and bleed again.
Cancel: I did not complete this guide.
10 other people completed this guide.
Special thanks to these translators:
100%
These translators are helping us fix the world! Want to contribute?
Start translating ›
17 Comments
Danke habe mit eurer Anleitung
Meine Pumpe wieder zum Laufen gebracht
Mit freundlichen Grüßen
Dierk aus dem Schwabenland
Hallo Dierk,
danke für deine Rückmeldung!
Es freut mich, dass es geklappt hat.
Viele Grüße aus Niederösterreich
Franz
Franz -
Alles gut beschrieben soweit, nur musste ich noch etwas weiter gehen, um meine Pumpe wieder in Gang zu bringen... Die Pumpe in meiner Solaranlage war zusätzlich auch noch mit altem, verbranntem Glykol verschmutzt, das ist ähnlich zäh wie Teer. Das einzige, was da noch hilft, ist Farbentferner /terpentin, danach lief die Pumpe besser als jemals zuvor... Keine Angst, etwas kaputt zu machen, meine lief eh nicht mehr, danach aber wie ne eins. Brennspiritus reicht nicht, hab ich probiert. Einweichen, durchspülen, fertig. Kondensator checken, meiner war ca 10 jahre alt lieferte nur noch 0,9 statt 2,5 NV... Nach Reinigung und Austausch läuft alles wie am ersten Tag, die Pumpe hält sicher noch viele Jahre.... Hoffe ich zumindest...
Hallo North70,
danke für die Ergänzung!
Viele Grüße
Franz
Franz -
Tolle Anleitung! Schritt 11 (Austausch des Anlaufkondensators) behob das Problem, Umwälzpumpe läuft nun seit paar Wochen störungsfrei. Der alte Kondensator hatte nur noch 13 Prozent seiner ursprünglichen Kapazität (2 µF).
