Ecodan system HW override

[athlonoc]

I get several power cuts every year and when that happens, I've learned to understand the system automatically overrides to heat up the HW cylinder.

In my scenario I have my HW set to 3am and 3pm scheduled heat. Set to 48 with a drop of 8

This work well for me and with my solar array and batteries it's become the most efficient way to keep HW in my house 24/7

 

The problem or situation I have encountered today. The power went off for a few seconds then straight back on. This defaulted to heat up the HW cylinder as it always does, but since changing the heat method to scheduled, it wasn't heating up the tank. I am assuming it's then waiting for the time of the schedule to kick in.

 

As we are going through a cold snap and my CH is on all the time set to a specific temperature, it's caused a problem.

 

The HW schedule stops the HW Cylinder from heating it, but it means that the CH isn't on as it's waiting for the HW cycle to complete.

 

Is there a way to stop the forced reheat of the HW Cylinder with this system.

 

If I wasn't at home to witness the power cut, then my CH would not be on for the duration of time until the HW schedule kicks in. 

 

Hope this is clear and makes sense.

Thank you

[JohnMo]

Think you have the task of going the manual and the actual settings. There should be something that is flagged to do DHW as a priority after a power cut. It's not a normal ASHP behaviour. Normally resumes the last mode active.

[athlonoc]

This is what I found printed on the Ecodan Installation Manual, under troubleshooting

 

25. The FTC unit that was running in the heating mode before power failure is running in the DHW mode after power recovery.

The FTC unit is designed to run in an operation mode with a higher priority (i.e. DHW mode in this case) at power recovery.
• Normal operation.
• After the DHW max. operation time has elapsed or the DHW max. temperature has been reached, the DHW mode switches to the other mode (ex. Heating mode).

 

This would suggest this is how the Ecodan system operates and I can't find a way to turn it off, to prevent my situation happening.

Last year we had 6 power cuts in our area. It's not a problem in the warmer months when the Heating isn't on.

[JohnMo]

Manufacturers trying to be clever, without stepping back to understand what happens in reality.

 

Ways around it?

[athlonoc]

This is what I found printed on the Ecodan Installation Manual, under troubleshooting

 

25. The FTC unit that was running in the heating mode before power failure is running in the DHW mode after power recovery.

The FTC unit is designed to run in an operation mode with a higher priority (i.e. DHW mode in this case) at power recovery.
• Normal operation.
• After the DHW max. operation time has elapsed or the DHW max. temperature has been reached, the DHW mode switches to the other mode (ex. Heating mode).

 

This would suggest this is how the Ecodan system operates and I can't find a way to turn it off, to prevent my situation happening.

Last year we had 6 power cuts in our area. It's not a problem in the warmer months when the Heating isn't on.

Edited Saturday at 15:39 by athlonoc

[athlonoc]

Installing a UPS so the power interruption doesn't cause this to happen. 

As it seems there isn't anything I can alter in my Ecodan system, then it's either put up with or install UPS.

 

Bit of a shame unless anyone knows any different.

[JohnMo]

My cylinder and heat pump are long from each other and it was difficult wire, so I use the following - cheaper than a UPS

 

A normal cylinder thermostat - like this - https://www.buildandplumb.co.uk//plumbing-heating-c36/heating-c264/heating-controls-c219/pipe-cylinder-thermostats-c358/eph-controls-eph-digital-cylinder-thermostat-with-high-limit-edbs-p11357/s29376

 

This operates via a time switch. So I have time and temperature sorted, this then powers a radio switch, which in turn powers a relay - but you could just use a wire to power a relay.  The relay just moves to simulate the cylinder temp sensor, one setting is a resistor that simulates 20 degs, the other 50 degs. The heat pump controller is looking for 45 degs for DHW.  So call for heat, relay moves to give a resistance equal to 20, once cylinder thermostat is happy relay is switched off, and heat pump thinks the cylinder is at 50 degs, so switches off all calls for DHW heating. 

[Beelbeebub]

Could you install something between the cylinder sensor and HP that basically tricks the HP that the cylinder is at temperature after a power cut?

 

Depending on the sensor it could be as simple as a relay and resistor. 

[athlonoc]

Thank you both.

Give these some thought and looking into.

 

Simple answer is there is nothing within the Ecodan but there are work arounds