Installation Guide for the SolaStat™-Plus-ET
Version 1.2 – July 2011
Page 24
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LUMBING
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Disclaimer
For full information on compliance and safety standards for solar hot water
systems the appropriate local standards must be referred to. All plumbing to
be carried out by qualified plumbers only.
We provide the following information as a guideline only to help obtain the
greatest efficiency from the system. Any information supplied here is based
on feedback to us by experienced solar hot water professionals and in no
way represents a complete guide to plumbing such a system, as we are not
plumbers and do not represent ourselves as such. Best plumbing practices
must be used in all instances.
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. For this reason Senztek NZ
Ltd recommends any installation is
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.
Non Return
Valve /
System
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
get caught in the valve seat.
Pressure
Relief Valve /
System
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.
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