Grundfos CH pump stops

[Pongolek]

When I turned on the heating with the temperature controller, the Icos HE12 boiler and the Grundfos UPS 15-60 130 pump would turn on. The radiators would heat up. Unfortunately, the pump would turn off after about 25 minutes. The boiler would start bubbling and knocking without temperature circulation. The pump would buzz slightly after stopping. I thought that maybe there was a problem with the capacitor - the installation is 15 years old. After replacing the capacitor, the same thing happened, but the pump only worked for a few minutes. When the water pump was still warm, it would not turn on, and you could hear a quiet buzzing sound. Only the boiler would start. I opened the pump. The impeller is not blocked. The pump stops at each of the three speed settings. Is it time to replace the pump?

 

[texasholden1980]

If the pump has a continuous 230v power supply throughout the period then does suggest the pump is faulty and needs replacing. Even if the impeller spins freely when turned manually if you have developed a short on the windings then new pump needed I'm afraid - although 15 years isn't bad!

 

[Pongolek]

Thanks. I think the same. I was hoping that maybe some temperature sensor was damaged but I read that there is no sensor there.

 

[Pongolek]

I replaced the pump. It works fine.