Hydraulic Unit; Final Commissioning - Dunkirk DCC-150 Installation, Operation & Maintenance Manual

15.1 HYDRAULIC UNIT (DHW)
For special areas, where the water is harder than 20 °f = 200 ppm or 12 grains/ gallon (1 f° = 10 ppm = 10 mg/l), install a
polyphosphate dispenser or an equivalent treatment system, compliant with current regulations.
LEGEND
A DHW exchanger fixing screw
B DHW priority sensor with filter
Boiler/system drain tap
C
(C-1 & C-2: access to tap C - bottom of boiler)
D Boiler / system filling tap
E DHW temperature NTC probe
F
Low water cutoff
15.1.1 CLEANING THE COLD WATER FILTER
The boiler is fitted with a cold water filter located on the hydraulic assembly (B). To clean, proceed as follows:
• Drain the domestic hot water system.
• Remove the nut on the DHW priority sensor unit
• Pull out the flow sensor and its filter.
• Remove any impurities.
NOTICE
When replacing and/or cleaning the "O-rings" on the hydraulic assembly (DHW), only use Molykote 111 as a
lubricant, not oil or grease.

15.2 FINAL COMMISSIONING

• Allow the heating system to heat up, then balance the system to achieve the necessary temperature difference across the
heating supply and return pipes at the boiler and check the system for proper volume and pressure. (see section 2.7:
"AVAILABLE PUMP HEAD FOR CENTRAL HEATING" and section 2.8: "SYSTEM VOLUME").
• Turn off the boiler.
• Thoroughly flush out the water pipework and clean the filters in the heating return and supply water isolating valves.
• Repressurize the system.
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240011373, REV D (05/02/16)