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Operation and Maintenance Instructions
Envistar Top 04-21
DSET.181201.00.EN
Continuous product development may give rise to specification changes without notice.
Additional maintenance for ThermoGuard (code ATTV)
1. The ThermoGuard coil must be fitted with a safety valve, the function of
which should be checked regularly (at least once a year). If you see that the
valve is leaking, this is normally due to impurities from the pipe system that
have accumulated on the valve seat. In normal cases, it is sufficient to care-
fully turn the valve knob and in this way “flush” the valve seat clean. If the
safety valve continues to leak, you will have to replace it with a new one of
the same type and with the same opening pressure.
2. Any shut-off valves on the supply or return lines may not be closed if freez-
ing temperatures are likely.
3. If a ThermoGuard coil has frozen, let it thaw completely before restarting
operation. If the heat recovery unit is installed upstream of the coil, it is often
sufficient to run heat recovery to thaw the coil. If this does not work, some
other external heating source will have to be used for thawing the water coil.
Important! To ensure correct ThermoGuard coil function, the entire coil must
be allowed to thaw before returning it to full operation. Make sure that water
is circulating in the entire coil when you start it up.
