Managing the heat dump... Forum

Hi Number Six,  My reply to you is below in green,  hope this helps..

Simon.

NumberSix said:

Lets say you have enough heat in the cylinder to meet morning shower needs, and it's a bright summer morning, the head-dump rad (off the the return pipe to the panel via three-way-valve) is in the main bathroom, would it be possible to manually over-ride the Resol controller head-dump setting to send heat to the the head-dump rad in the bathroom?

The heat dump only comes into the solar panel circuit when the three way valve is activated and the flow is sent through the heat dump rad.  You decide at what temperature this will be and programme the controller accordingly,   e.g.  when the bottom of the cylinder is at 70 degrees but this can be any value really. You also decide what temperature to return the solar circuit to heat the cylinder so you could specify 65 degrees if you were dumping at 70.  This means that when the cylinder has cooled to 65 degrees the divert valve switches the flow away from the radiator and back to the cylinder.

My thinking is to warm the bathroom without having to power up the heating system. Any thoughts?

Our experience with solar heat dumps indicates that it is difficult to rely on excess energy to perform other tasks on a regular basis.  The solar system has been sized to cater for your DHW needs and it's mainly when you are not using hot water - e.g. when you are on holidays,  that overheating becomes an issue and the heat dump activates.  If you are looking to heat your bathroom by this method you will need to oversize your array accordingly and assume it's only really going to be heated in summer. 

You would also have to take into account the fact that people will be taking showers in the morning thus dropping the temperature of the bottom of the cylinder allowing for the solar panel to collect heat and send it to the cylinder and the heat dump will not be activated.  The heat dump will probably only come into effect later on in the day in this scenario.

(I'm thinking of possitioning the controller outside hte hot-press for visibility and ease of access.)

This is a good idea as it will allow you to become aware of the water usage pattern in your household.  It's also handy to know the temperature of the water at the top of the cylinder so you know how long you can spend in the shower!   On our pump stations you can easily separate the controller from the pump unit,  extend the cables and position the controller where you want it to be.