Pulsacoil 2000 Mystery!

Suddenly, the hot water is hardly warm. I've had problems with the pump when I am away for a while and need to kick-start it with a light tap, but since September the flat has been occupied and did not have that problem.

Anyway, the first thing I did today was to start to undo the nut in the pump and immediately I could hear water running as if the tank was being replenished. If I tighten the nut, the running stops... I could not understand where the water was coming from or going to as all domestic taps were closed and there was no flooding under the tank.

Then, I decided to look inside the Header Tank: it was very, very low. I filled it with bottled water and now must wait til morning to see if the overnighjt heating sorts out the problem. But I thought that the tank's water was pretty much permanent, and that the hot water that comes out of the tap, simply ran through the hot water in the tank in some sort of serpentine and acquired temperature by exchange. So, I am at a loss about this running of water for long periods as if the non-existing hot water that we try to get out of the taps, comes directly from the main tank, that then needs to be refilled, But if so the refilling only happens if I loosen the nut in the pump.

Mystery!

Unit was low, might still be!
Bottled water? Any water will do.
Pump sounds like air. Bleed it with out the pump running.
Mike
MGC/H2O
Norfolk

" Bleed it with out the pump running."

How do you do it? Where is the bleeding point?

Thanks

You bleed it by removing big screw on front of pump.
Try switching power on for a few seconds then off.
Mike

Thanks Mike

That has led to a new discovery: if I loosen that screw before having a shower, I can hear the water circulating (now I have been told) in the heat exchanger and after the water in the shower is hot!
After the shower, I have to wait for the pump to stop (it takes around 10/15 minutes) and tighten the screw. While it is working thre is no dripping out through the screw. but as soon as it stops, the dripping starts.

So, it appears that my problem is with the pump; but why should the pump only work with a loose screw, that when it is not working lets water out?...

The pump will not drip much when it is running with the screw out.
Only when the pump has stopped.
Is it all working ok now?
Mike

No. IT seems to work if I loosen the screw, but of course, as soon as the punp stops because it is mot being used, the drip starts and I am forced to tighten the screw. Then, I get no hot water!

I cannot understand what is happening, other than maybe the system needs air for some reason and the loosening of the screw allows that

mike wrote:The pump will not drip much when it is running with the screw out.
Only when the pump has stopped.
Is it all working ok now?
Mike

It has been suggested that I need to bleed the system, not just the pump.

How do I do that, please?

Regards