Pulsacoil 3 problem

[Junq]

I have a Pulsacoil 3. The pump was pulsing for prolonged periods even when not running the hot tap so I changed both the DHW wet sensor and the PHE dry sensor.

Now when I run a hot tap the pump starts for approx. 5 seconds then switches off. If I close then reopen the tap the same happens.

If I let the thermal store lose some heat then try again the pump runs for longer before switching off. Then when there is not much heat in the store the pump will run and not switch off until I turn off the tap (the expected normal behaviour).

I suspect the pump is being switched off due to too much heat in the store going through the heat exchange to the DHW sensor.

The pump seems OK because if I remove the dry PHE sensor as a test then run the hot tap, the pump starts and runs until I turn off the tap. then the pump continues in a reduced mode (I suspect an error failure mode due to the dry sensor not registering).

I checked the off peak immersion heater thermo rod (I only use off peak Immersion heater) and it was sealed set at 85c.

Could this be the problem as I suspect it should be no more than 77c.

 

[Agile]

I think those are designed to be run at 84 C otherwise there is not enough heat stored in the cylinder.

The only useful heat in those is the temperature above 55 C for hot water delivery.

Not a very clever system although it does the job when it is new and working properly.

Tony

 

[Junq]

Thanks Tony but this extract from the manual states different from what you say. Therefore could that be the problem

"

The immersion heaters used are 14” 3kW low watts


density units with incaloy 825 immersion sheaths, and


matching 11” rod thermostats which should be set to


77C. They are BEAB approved and have been chosen

to meet the requirements of the Maxistore specification


produced specially for Ecomony 7 products by the


Electricity Industry.

"