Xylem IM 16 Seal-less Centrifugal Canned Motor Pumps For Instant Hot Water Recirculating System (obsolete) - Manual (Page 7)

7
Trouble Shooting
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
(see below).
• The check valve/non-return valve is mistakenly installed on the inlet side of pump or in the wrong
direction. The check valve refers to a swing check not a spring check.
• The inlet side shut-off valve is closed or clogged.
• There is air is trapped in the pump housing (turn the pump on and off several times to see if the air
pocket can be “bumped” out of the pump and if not, then open the hose bib for manual venting).
• There is debris blocking the rotor.
• The rotor bearing has worn due to dry running causing the rotor to wobble during operation.
• 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. If so, add a check valve/non-return valve on the
cold supply line above the return line tee connector.
Pump Operating Intermittently or Not at All:
• No power to the pump.
• There is debris or foreign matter in the pump.
• The thermostat is not functioning properly (see page 6 on thermostat operation).
Water Taking Too Long to Get to Faucet/Tap:
• The hot water supply from the water heater is exhausted.
• 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.
• The check valve/non-return valve is installed backwards.
• The pump is not operating.
• The timer is not operating properly.
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.
Warranty
Laing recirculation pumps are warranted against defects in materials and workmanship for 24 months from
the date of manufacture (see mfg. date label on pump) or twelve (12) months from date of user purchase,
with proof of purchase, whichever is later. In order to receive warranty considerations, the product must be
returned prepaid to the company from which it was originally purchased. If the pump is found defective, the
pump will be replaced or in the case of wholesale customers, appropriate purchase credit will be issued. Prior
to returning any defective pump to Laing for warranty consideration, contact the Laing factory for an RMA
tracking number. Any claim for consequential damages resulting from a pump malfunction is not covered by
the Laing warranty. Additional warranty details are available on request
.
WARNING: - Excessive System Pressure Hazard - The maximum working pressure of the
pump is listed on the nameplate - Do Not Exceed This Pressure. Failure to follow these
instructions could result in serious personal injury, death and/or property damage.
Safety Requirements
Mechanical Safety
WARNING: - Excessive Pressure Hazard Volumetric Expansion - The heating of water and
other fluids causes volumetric expansion. The associated forces may cause failure of system
components and the release of high temperature fluids. This can be prevented by installing
properly sized and located compression tanks and pressure relief valves. Failure to follow
these instructions could result in serious personal injury, death and/or property damage.