How does the PV divert function work on the Edel?

The “PV divert” feature depends on the functionality of the customers’ existing Solar PV inverter, not the Edel. The PV inverter or an add on relay card for the inverter, needs to be able to tell the Edel via two volt-free signals, that either no PV, some PV or “lots of” PV is available – that is all.


If the customers’ PV Inverter can send two independent volt-free signals to the Edel cylinder, it can then tell the Edel to either heat water to the standard set point (ie; 50C) when no PV is available, or heat water to 60C on compressor (PV Eco mode) when some PV is available or heat water to 60C using compressor & element (55C on EDL170) and then above that, element only to 65C (PV Max mode) when there is an excess of PV available.


The amount of free PV energy is determined by the settings on the PV inverter & the amount of sunshine. Where else that energy goes, or exactly how much is used in the home or exported is not controlled by Edel.

Example Setup:


The installer will need to isolate the Edel and the Solar PV system and ensure all electrical supplies are proven dead.

The ducting and top cover of the Edel will need to be removed to access the wiring centre on the Edel. 

Ideally, a 4 core flex should be used to connect between the Edel and the Solar volt-free relay board. There is a rubber grommit next to the mains flex input on the Edel for the cable to be safely routed out of the Edel.


There are two connections on the PCB within the Edel. They are shown below:

It is essential that the connections between the Edel and the Solar PV inverter controller / relay board are volt-free. If 230v is connected to terminals 1 or 2 of the Edel, it will damage the product. 

It is also forbidden to disconnect the immersion element and use a Solar PV optimiser directly onto the immersion, or to "piggyback" onto the immersion using a Solar PV optimiser product, as the Edel must have direct control over the immersion element.

Once these connections are made, the electrical box cover must be securely replaced, the Edel lid re-fastened and air duct work reconnected to the top of the cylinder. Once the connections are made to the PV inverter / relay board and covers replaced, mains can then be switched back on.

To configure the Edel to use PV mode, follow these steps.

Press MENU button and turn dial to INST.MENU. Hold down MENU and CLOCK buttons to enter the Installer settings. PV mode is within the Installer menu:



Configuring the Solar PV system.


We cannot give explicit detailed instruction on how to configure the Solar PV system to talk to the Edel, as it will depends on the make, model and features of the Solar PV system installed. 


The Solar PV system needs to be configured to switch the relay on connected to the "PV Eco" connection, if there is at least 700 watts of power being exported (the compressor draws max 700w). There should be a minimum delay of 5 minutes for the relays to prevent excess switching as the clouds briefly cover the PV array.

If the PV eco relay is on AND there is at least 1200 watts being exported to the grid (700w for compressor and 1200w for immersion), then the Solar PV system should then be configured to enable the PV Max relay.  This will command the heat pump to use the compressor (if below 60C water temp on EDL200/270 or if below 55C on EDL170), and immersion element to run together. Where the tank is above 60c/55C as mentioned, and there is a PV Max signal, just the immersion will run until the cylinder reaches 65C. 

An example of a Solar PV system is the "Solar Edge Smart Energy Relay" which is documented here and here

We do not endorse a specific PV inverter or relay system and it is the responsibility of the installer to check with the PV inverter manufacturer that their equipment can provide the necessary volt-free signalling and can be configured to respond according to changing solar conditions. 


Note, the Edel is not using "SG Ready" signalling. See below truth table on how Edel responds:


PV Max input (2)PV Eco input (1)Action
00Edel following standard set point temperature as set by customer.
01Edel set point raised to 60C, compressor only operation
10Edel set point raised to 65C, compressor & immersion runs to 60C for EDL200/270 (55C for EDL170) and immersion only above this until 65C reached.
11Edel set point raised to 65C, compressor & immersion runs to 60C for EDL200/270 (55C for EDL170) and immersion only above this until 65C reached.



What is shown on Edel screen:


If the Edel is running normally (no excess PV available), and the tank is below the set point, that set point is shown on screen and if the compressor is running, the compressor and fan symbols will appear on screen:


If some PV energy is available (PV Eco mode), the PV icon appears in the top left of the screen and the set point is changed to 60C:


If plenty of PV is available (PV Max mode), the PV icon appears in the top left of the screen, the set point is changed to 65C and the lightling bolt symbol also appears, showing that the immersion element is also being used:

Applicable Models

Edel – EDL170-520RF, EDL200UK-630RF, EDL270UK-630RF, EDL200UK-630, EDL270UK-630

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