Purging air from a Grundfos pump - Help Needed

championc

I wonder if anyone can help with purging air from a Grundfos pump. I'm using it as a circulation pump, but there is still air inside, because it is sloshing around and you absolutely hear it when the pump stops, like it drains out of it. If full, it should just hummmmm along. It is thermostat controlled, so is on and off now and again. I am running it with the screw removed. Bare drips come out. The brown water is coming from dirt in the cartridge, because the main outside burst on a few occasions. This is installed in Spain.

It had actually seized fully, until I started to remove the internal cartridge, tapping it out with a hammer, and it freed up. I didn't remove the cartridge, as it seems quite a tight fit,

Should I try any other approach to flush it out ?

Initially, this was the state of the inside of it

10-10-20

Hi championc, That's circulation pump for what... heating system or underfloor, or what? How is the muck getting in if its heating?

The pump should self purge air itself as the outlet is pointed upwards and the incoming water should be coming from the sealed pipework below, I'm wondering if it suggests that you have a bad seal on the pump body or on the inlet where the negative pressure is the highest. Or maybe you just have air in the system and no functional air vent/trap?

There seems to be tonnes of fresh ptfe tape there on that bottom joint... is that indicative of a previous leak or a mis-fit on the diameter of the fittings?

Other potential cause could be cavitation... but that's hopefully not what's going on here.

championc

It's a rooftop water heater. Water is fed up to it from the rising main, but I have now seen that there is no strainer on it. Given that water must travel over 5 metres to reach the apartment below, I have the pump to bring the hot water down to the apartment, rather than having to run the tap every time for over a minute before the hot water arrives at the tap.

Look up the Grundfos Comfort Valve - so you can have hot water right at the taps rather than wasting it. After all, in Spain, you pay for all water used.

But the local pipes network is a mess, with constant leaks. The boyo's dig a hole and to hell with how much mud and sand and whatever then gets into the system.

Anyway, I have run the pump now for the whole day, and it actually appears to have sorted itself out

The pump is controlled by this Inkbird Temperature Controller. When the probe sees a temperature below a certain level, it runs until it sees that temperature

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championc

SOLVED - By simply running the pump for the day with the bleed screw removed, and a bottle catching the drips.