en – Original Instructions
Installation, Operation and Maintenance Manual
39
7.5
Noise in the system
The pump should be virtually noiseless during operation. The rotor may make a brief but hardly
perceptible fluttering noise immediately after the pump is turned off. During normal operation,
an occasional air bubble may pass through the pump housing causing a momentary gurgling
noise. However, if noise at the pump persists for any prolonged period, correct the problem.
Cause
Remedy
Check valve installed on the inlet side of the
pump or in wrong direction
Check and correct the installation
Inlet side shut-off valve closed or clogged
Check and open or clean the valve
Not thoroughly air purged
See section 5.4 Air purge on page 31, if this
function is not available or not efficient, open
the hose bib for manual venting
In case of an Autocirc pump, turn it off and
turn the hot and cold faucets/taps on, to be
sure all air is purged from the system
Foreign objects in pump
See section 6.4 Disassembly on page 37
Worn bearing causing the rotor to wobble
during operation
Replace pump
If the return line connects to the cold water
supply at the top of water heater, the warm
water may be creating back pressure in the
cold supply line
Add a check valve on the cold supply line
above the return line tee connector
If the noise occurs when an Autocirc pump
turns off it is likely to be "water hammer" that
results from the closure of the built-in valve.
Water hammer arresters may be installed on
the hot and cold lines
7.6
Water taking too long to get to faucet/tap
The faucet/tap involved may be on a branch line off the main hot water supply line in which case
there may be a slightly longer wait for hot water to arrive than at faucet/tap directly off the main
supply line.
Cause
Remedy
Hot water supply from the water heater
exhausted
Check the water heater
Check valve installed backwards
Check and correct the installation
Pump not running
See section 7.3 on page 38
The timer is not operating properly.
Replace the timer
7.7
Signs of dry run
Dry run results from inadequate water supply to the pump, which prevents lubrication of the
bearing ball. It may be caused by operating the pump without water in the plumbing lines, which
may occur with frozen pipes, or by failing to turn the pump off when the system is drained for
servicing. It can also occur as the result of large air bubbles collecting in the pump housing and
preventing the flow of water over the bearing ball. If the problem is air in the system, check that
the air vent is functioning, that the system is properly purged of air and that the pump and
various system components are installed.
