Installation; Important - Plumbing Information - Dimplex A8M Installation Manual

4.

Installation

4.1 Important - Plumbing Information

NOTE: To simplify underfloor heating initial screed heating, it is essential to have a thermostatic mixing
valve on the underflood heating (UFH) manifold.
This allows the heat pump to run at higher temperature and capacity when the screed is cold.
• If multiple heat emitter circuits are installed, operating at different flow and return temperatures (such
as under floor heating and standard radiators), a mixing valve must be used on low temperature
circuits to prevent high temperature water from entering the under floor heating manifold.
• Isolation valves (non-return valve and ball valve with strainer), supplied in the Dimplex heat pump
hydraulics pack, allow the strainer to be removed and cleaned without having to drain the system.
• Existing hot water systems should be flushed prior to connection to the heat pump to remove all
contaminants and impurities, in accordance with the latest version of MIS3005.
• Flow and return isolation valves and piping must be fitted to each of the heat pump water connections
on the back of the heat pump, as shown in figure 1.
• The isolation valve on the return is also fitted with a non-return valve and a strainer (included in the
Dimplex heat pump hydraulics pack). This means that in order to clean the strainer, the system does
not have to be drained. Instead, it is possible just to close the isolation valves on the return and
remove the strainer. This way, the only water that will be lost from the system is that between the non-
return valve and strainer.
• The strainer must be fitted in order to prevent contamination of the condenser heat exchanger. If an
alternative strainer is used, it must be at least 7 microns in size.
• System should be pressurised and the system pressure must be checked once valves are re-opened.
• Direct condensate drain pipe to soak away or drain.
• All piping must be properly insulated and external length kept to a minimum.
• The return isolation valve provided in the hydraulics pack has a built in strainer to help prevent debris
entering the condenser and must be fitted.
• The system must be filled and flushed with clean fresh water to ensure the removal of all the air from
the installation.
CAUTION: When filling the system, always ensure that clean, fresh water is used. Using dirty or
untreated water may cause severe damage to components and may affect the efficiency of the system
when operating.
• Air bleed points must be installed at the highest point in the system; in particular, the installer must
remember to install an air bleed on the heat pump pipe if it is a local high point since there is no air
bleed point on the heat pump itself. Dimplex recommend the use of a power flush and purge cart to
facilitate this process.
Millbrook House, Grange Drive, Hedge End, Southampton, SO30 2DF
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0844 879 3587
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