ᐅ Circulation Pump in a Viessmann Gas Heating System

Created on: 23 Oct 2012 20:42
L
latscho
L
latscho
23 Oct 2012 20:42
Hello everyone,
I would like to save some electricity by replacing the circulation pump of my Viessmann gas boiler.
Unfortunately, I am not sure which one should be replaced, as I have two pumps (one Grundfos UPS and one Biral).
One pump is connected to the heating system and circulates the hot water through the heating pipes. From this line, there is a branch with another pump that is connected to my hot water storage tank on the boiler’s supply line.
Should both of these pumps be replaced or just one? I hope I explained this clearly.

Thank you very much for your advice.
€uro
24 Oct 2012 12:39
latscho schrieb:
...I would like to save some electricity and replace the circulation pump of my Viessmann gas heating system.
It is possible that the existing pump is hydraulically correctly sized, and replacing it could turn into a money pit.
From the description, it sounds like a peculiar setup. Please share a photo or a hydraulic circuit diagram here.

Best regards.

NB: If you don’t know much, it’s better to avoid making things worse by trying to improve them!
L
latscho
26 Oct 2012 17:20
Here are a few photos to make it easier to understand.



Heating system with pipes, valves, pressure gauges, and boiler in the heating cellar.


Compact heating or plumbing system with pump, copper pipes, and valves
L
latscho
29 Oct 2012 13:30
Can someone explain why there are two pumps installed in the heating system? I would like to take advantage of the subsidies currently available in Hesse. Thank you.
Musketier29 Oct 2012 14:10
Since no one is responding to you, I’ll share my layman’s knowledge here.

To my understanding, hot water is always preferably heated first.
So, when you draw hot water and cold water flows from the pipe into the hot water tank, your left* pump is activated and the circulation for hot water heating starts. Inside the tank, the heating water flows through coils next to the domestic water and heats it up. There is no water exchange between the two.
Once the hot water tank reaches the set temperature, the left* pump stops and the right pump for the heating circuit starts.
That’s why there are always at least two pumps.

While the old pumps consume a lot of energy, the new low-energy pumps are by far more energy-efficient (Energy Class A). Most likely, the pump for the heating circuit runs most frequently, so it should primarily be checked for efficiency.

I can’t say anything about the replacement itself.

* I assume from the picture that your hot water tank is on the left, and therefore the pump for the hot water is also on the left.
L
latscho
31 Oct 2012 12:31
Correct, on the left side of the picture is my hot water storage tank.
Do I understand correctly that the pumps only operate when water is needed?
Or does the pump for the heating circuit run continuously?