I've just had this develop on my Technika IV (rotary pump - water tank). I think the heading sums it up and I am looking for inspiration.
When first turned on (ie cold) if I lift the lever I immediately get water coming out of the screen and the pressure gauge goes to 8/9 bar, which is usual.
The machine starts to heat (boiler pressure ok) but when the group head gets to just over 80 degrees according to the group head thermometer it stops heating. The group head thermometer would normally get to 96-98 degrees and stabilise depending on ambient temps.
If I then lift the lever, the pump comes on but there is no water coming from the screen and no pressure on the gauge for a few seconds. After the few seconds water does come out and the gauge reading is what I would expect. Repeating that 10 seconds later, I still get a delay, even though I assume the system is primed.
I left the lever at the halfway mark and it seemed to be heating, but as soon as I activated it, the temp dropped.
If I put a blind filter basket on, after the delay it will go to about 10-bar which is what has been normal.... so the pressure from the pump seems okay.
It appears the thermosyphon might have drained and so the pump appears to not be primed... and there is no water circulating to heat the group head once it gets to a certain point.
I assumed maybe the seals in the group head were leaking (there were a couple of drips) and so the system was depressurising. I have changed the seals, but still nothing. The fact that it holds pressure with the blind basket makes me think it is tight. And - there are no water puddles under the machine.
I recently descaled the machine and did get some odd pressure readings for a while (gone now), so dislodged calcium passed my mind, but I would expect a blockage to be a blockage - hot or cold.
Any thoughts?
When first turned on (ie cold) if I lift the lever I immediately get water coming out of the screen and the pressure gauge goes to 8/9 bar, which is usual.
The machine starts to heat (boiler pressure ok) but when the group head gets to just over 80 degrees according to the group head thermometer it stops heating. The group head thermometer would normally get to 96-98 degrees and stabilise depending on ambient temps.
If I then lift the lever, the pump comes on but there is no water coming from the screen and no pressure on the gauge for a few seconds. After the few seconds water does come out and the gauge reading is what I would expect. Repeating that 10 seconds later, I still get a delay, even though I assume the system is primed.
I left the lever at the halfway mark and it seemed to be heating, but as soon as I activated it, the temp dropped.
If I put a blind filter basket on, after the delay it will go to about 10-bar which is what has been normal.... so the pressure from the pump seems okay.
It appears the thermosyphon might have drained and so the pump appears to not be primed... and there is no water circulating to heat the group head once it gets to a certain point.
I assumed maybe the seals in the group head were leaking (there were a couple of drips) and so the system was depressurising. I have changed the seals, but still nothing. The fact that it holds pressure with the blind basket makes me think it is tight. And - there are no water puddles under the machine.
I recently descaled the machine and did get some odd pressure readings for a while (gone now), so dislodged calcium passed my mind, but I would expect a blockage to be a blockage - hot or cold.
Any thoughts?
- Is there a drain valve that might be heat effected?
- Would the pump be affected by heat - even though it has normal pressure once primed?

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