Daikin super inverter

[Craig Johnston]

Hi guys, I'm having a issue with a daikin super inverter. It keeps showing a e4 fault. I have decanted the unit and charged by weight. It was all ok. I have checked my pressure transducers and they are fine. I have also changed the board ( swapped from a redundant unit)
Whenever I arrive it is in a e4 fault (low pressure) when I reset the unit it works fine but the condenser freezes up very quickly.

I'm guessing I have a restriction or a faulty eev.

Just like to know your thoughts.

Thanks

[Brian_UK]

Have you checked the temperature sensors?

[Craig Johnston]

Yeah I've changed the thermistors but again from the redundant unit.

[frank]

Whenever I arrive it is in a e4 fault (low pressure) when I reset the unit it works fine but the condenser freezes up very quickly.

I assume that you are in 'Heating' mode?

[Craig Johnston]

Yeah. It's on a biddle door curtain so the shop would kill me if I put it in cooling.

[frank]

Do you have a full model number?

[Slim R410a]

Low pressure sensor?
http://www.refrigeration-engineer.com/forums/showthread.php?16624-Daikin-E4&highlight=

[Craig Johnston]

Tested the low pressure sensor already. Mod rzq250c7y1b biddle is UK.city m-200-dk-f

[Brian_UK]

Have you checked that the Biddle unit is clean and with the correct airflow.

[Craig Johnston]

Yeah filters and coil clear with great airflow

[narkom]

What is the outdoor temperature?

[frank]

On page 24 the piping diagram shows an expansion valve feeding the outdoor coil in heating mode. This may be starving your coil and causing the low pressure fault http://www.daikintech.co.uk/Data/Split-Sky-Air-Outdoor/RZQ-CY/2015/RZQ-C7Y1B/RZQ-C7Y1B_Databook.pdf

[Craig Johnston]

Cheers Frank, thought it was the expansion valve. I'll replace it and keep you updated.