Table: MECH Advanced Troubleshooting

Complaint	Cause	Solution
Leakage
Note: Close all valves on the plumbing bracket under HIU and the mains water valve.
Weeping from connection	Coupling nut is loose / Gasket missing	Tighten union nut / Insert gasket
Weeping from temperature sensor	O-ring is missing/ O-ring damaged	Replace temperature sensor
Differential pressure control valve  leaks	Connection nipple (s) loose	Tighten connection nipple (s)
Differential pressure control  valve damaged		Replace valve
Other components or pipes leak	Component or pipe damage	Replace component or pipe
Central Heating System does not heat
Radiators are not warm	Valves on plumbing bracket closed	Open valves on the plumbing bracket
	Radiator valves closed	Open radiator valves
	Air in heating pipe	Bleed air from heating system
	Tap is open	Close tap
	Filter blocked	Clean filter
	Pressure and / or temperature of district heating network does not conform with demand	Check pressure and / or temperature of district heating distribution network
	Possible defect in temperature sensor or heating valve	Contact Engineer
No Domestic Hot Water
No water	No water pressure	Check / open main valve  Check flow limiter for proper placement  and / or blockages
Domestic Hot Water is not at the right temperature
Water is not hot	Pre-payment and / or return valves closed	Purchase energy and / or open return valve on heat distribution network
	Low flow rate,1 lt / min is not being achieved	Open the tap to achieve at least 2 lt / min and / or open valves fully
	Flow Sensor defect	Replace flow sensor
	Pressure and / or temperature of district heating network does not conform with demand	Check pressure and / or temperature of district heating distribution network
	Filter blocked	Clean filter
	Possible defect in temperature sensor or heating valve	Contact Engineer

Insulation Cover will not close
Cover does not close properly	Cables caught between sheathing	Make sure cables are in slots provided and keep cables free of the insulating jacket
	Pipe spacer is not seated correctly in the slot	Press pipe spacer into slot fully
	Heat meter hitting against the inside of case	Check correct installation dimensions and adjust position as required
Sound
NOTE: It is normal that the HIU makes noise when hot water or heating are active.
Rattling sound	Flow sensor incorrectly installed	Flow Sensor correct installation (up arrow)
Other Sound		Contact Engineer