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SolaStat-Eco Trouble-shooting Guide.
This is intended as an initial guide to minimise service calls.
Introduction.
Any solar hot water system involves professional level plumbing and water much hotter than
would normally be seen in standard domestic hot water systems, any installation must be
carried out by a registered and qualified plumber. All parts including the pump must be rated
for the elevated temperatures found in solar hot water systems.
Solar Hot Water Specifics.
1. Tempering valve.
There is a huge amount of energy radiated by the sun. It is not uncommon for the water from
the solar collector to exceed 100 C (under pressure).
Therefore it is vital a tempering or „mixing‟ valve is fitted so the domestic supply from the tank
does not burn the end users. The tempering valve must be installed to best plumbing
practices. The tempering valve must be rated to handle these elevated temperatures.
2. Non return valve.
Hot water rises and cold water falls. If the solar collector is colder than the tank, such as during
the night, the hot water from the tank can self thermosiphon up to the collector. The collector
now radiates the heat to the cool night air and the water descends back down to the tank. To
stop this
loss of hot water at night or during cloudy skies there has to be a one way or „non
return‟ valve fitted.
The failure of this non return valve is a common problem with solar hot water systems. The
orientation
of the valve as per manufacturer‟s instructions is critical. Also the valve sometimes
will not close when swarf or other debris gets caught in the valve seat.
3. Pressure relief valves.
Solar hot water systems can run much hotter than standard domestic hot water systems.
Hotter water expands more and needs high quality pressure relief valves to avoid possible
catastrophic rupturing somewhere in the system, probably the tank.
Qualified plumbers using best industry practice must decide on adequate pressure relief
valves, the number and placement of them.
4. Air Relief Valves.
It is important that air relief valves are fitted (especially in a low pressure system) to the
highest point of both the feed to and the return from the solar water collectors. Otherwise air
locks can occur within the piping etc., and not just the pump. (An air lock in the system will
increase the head that the pump is working against and for some installations this is too much
and the water ceases to circulate. For systems where air locks occur, the pump may need to
be set to a higher speed or a higher head pump installed).
