Laing Thermotech Trouble Shooting Guide
SM/SMT and UC/UCT Pumps
Q. My hot water recirculation system has
stopped working, do I need to replace my pump?
A. The typical life of a Laing pump is 5 years
plus. The only moving part in the pump is the rotor
(also known as an impeller) assembly, so this is the
main wear point of the pump. You may only need to
replace the rotor.
To check it, do the following:
- Turn the pump off and close the valves on either
side of the pump. If no shut of valves are present it
will be necessary to shut of the water supply to the
house and open the fixture farthest from the water
heater to drain the supply line. You may also want
to have a bucket handy to catch the draining water
from the return line once you remove the pump.
- Unscrew the collar ring that holds the motor to
the pump housing. The motor will then separate/drop
away from the housing exposing the rotor.
- Place the pump on a level surface like a table
or work bench. Turn the pump on and observe the
rotor. It should spin up “counter-clockwise” in a
tight smooth spiral. If it does this, but wobbles
or knocks about, it is worn and must be replaced.
- If the rotor does not turn, shut the pump off.
Remove/pull the rotor off of the bearing with your
finger tips and examine the bearing ball. If this
ceramic bearing ball is missing, damaged, or loose
on its mounting pedestal, the motor must be
replaced. NOTE: the bearing ball must be perfectly
smooth without wear to be serviceable.
- “Gently” set the rotor back on the bearing ball
(do not push) and apply power. If the rotor now
turns, a replacement rotor will complete the repair.
If the rotor again fails to turn, the motor must be
replaced. NOTE: a slight magnetic “pull” or
vibration from the rotor, or if the motor becomes
warm during this test, a failed internal motor coil
which can not be repaired is most likely the cause.
Q. My pump is making a lot of noise when it
runs and is very hot to the touch.
A. Laing pumps run hot by design with 150+
degrees F operating temp not uncommon. Noise typically
indicates a worn rotor. Follow the trouble shooting steps
detailed above to isolate the problem.
Q. Why did my rotor/impeller fail so quickly?
A. Typically, when we see a rotor fail in a short
period of time, it is a result of air in the recirc
piping which eventually will work into the pump. This
causes a dry run situation which creates premature wear
to the carbon bearing in the rotor assembly. Refer to
the installation guide to ensure that all of the proper
installation procedures have been followed. Ensure that
your system is installed EXACTLY as illustrated on page
three of our installation manual with all of the
components show installed. Also ensure that the system
is initially purged of air by using the hose bib.
Q. My pump has all of the components shown in
your installation manual but is installed above the
water heater. Is this OK?
A. NO. The pump should always be mounted below
the water level of the water heater and pumping either
upward or in a horizontal direction (see flow
directional arrow on bronze pump housing). Mounting the
pump above the water heater or allowing it to pump in a
down-ward flow will increase the probability of trapped
air in your pump and will result in pump/rotor damage.
Q. Should I use a swing or spring type check
valve in my recirc piping?
A. Only a swing (flapper type) check valve must be
used and installed between the pump outlet and the
water heater. A swing check can be identified by a
large screw cap on top and small screw plug on the
side. A spring type check valve has a smooth body with
no access caps or plugs. NOTE: the check valve must
never be installed on the inlet side of the pump.
Q. Why is a spring check valve not
recommended?
A. The spring in this type of valve is sometimes
too strong for a Laing 303 to open. This will stop flow
and cause the pump to over heat and eventually fail.
Q. My pump connects to the bottom drain
connection of the water heater. Can I use the hose bib
on the bottom of the tank to purge (remove) air from my
recirc pump and piping?
A. NO. The hose bib on the bottom of the tank
will only serve to drain the water heater. You must have
a separate hose bib between the pump and the check valve
as shown in the pump installation guide.
Q. My system is installed per you installation
diagram but I am still having pump failures after a
short period of time.
A. What is the size of you return line? Our 303
series pumps should be installed with a ½” return line.
If you have a ¾” return you should be using our 909
series pumps. The overall length of the system is also
important. The Laing 303 series will handle
recirculation piping loops up to 250 feet (supply and
return). The 909-14 series will handle a loop up to 750
feet, and our 909-18 series will handle a loop up to
1000 feet.
AUTOCIRC PUMPS
Q. How to determine which faucet is the
farthest fixture/location from water heater where
Autocirc products should be installed?
A. Typically, it is the fixture where hot water
takes the longest to arrive. To check which faucet is
the farthest, select the fixture that you believe to be
the farthest from the water heater. Run the faucet
(sink or tub) until the hot water arrives. Now,
check other faucets in the home to see if you have hot
water immediately available. If you do, then you have
selected the correct faucet as the farthest location. If
you do not have hot water immediately at these other
locations, then either you did not select the farthest
faucet or you have branch plumbing NOTE For installation
where branch plumbing is involved or if you have a
manifold system.
AUTOCIRC 1 ACT-303-BTW – When is the BTRW Model
Recommended?
Q. My ACT-303-BTW does not provide me with
instant hot water.
A. Try this test.
Turn the pump off and let the system cool down for
30-40 minutes. Do not run any hot water through your
sink during this time.
- Turn the pump on; it should begin to run
immediately.
- Wait at the pump until it shuts off (usually 3
to 5 minutes).
- Immediately after the pump shuts off, turn on
the hot water and see if it is warm (95° F). I
suspect it will be.
- Leave the pump on and check water temperature
again in 10 minutes. Take note if your water is
warm for a few seconds, then cools down for a
period of time, and then starts to warm up again.
Q. My system did just what you described when
I checked the water immediately the water was warm and
quickly became hot but when I checked it a few minutes
later it was warm for only a few seconds and then turned
cool. Is my thermostat defective?
A. No, what is probably happening is that your
home is built on slab and the piping is running through
the slab. The water in this slab piping is cooling down
much quicker than the water in your Autocirc pump which
is where the thermostat is located. By the time the
water in the pump cools down sufficiently to allow the
thermostat to turn the pump on, the water in the slab is
already cool. The solution to this problem is to cause
the pump to turn on sooner. This can be done by raising
the "ON" temperature. We have a version of the Autocirc
model ACT-303-BTRW that has an adjustable "ON"
temperature which will allow you to raise the "ON"
temperature.
Note: You must cal LTI and receive a
return material authorization number (RMA) before
returning the pump. LTI phone number is:
619-575-7466
Q. When I tried this test, the water was
still cool immediately after the pump shut off.
A. If the pump ran but did not bring hot water to
the fixture where it is installed something is stopping
the circulation. It could be the check valve inside the
pump housing.
To attempt to check/free up this valve, do the
following:
- Turn the pump off and let the system cool down
for 30-40 minutes. Do not run any hot water through
your sink during this time.
- Turn the pump on, it should begin to run
immediately
- On the sink above the Autocirc, turn the hot
water faucet on for 5 seconds and then quickly slam
shut. Repeat this procedure 15 times on the hot
faucet, and then repeat this drill 15 times on the
cold faucet. This should free the diaphragm and
allow the pump to circulate.
If this does not work then, further trouble-shooting
via e mail/telephone with Laing Tech Dept will be
required. Always have your pump serial number handy
when contacting Laing Thermotech.
Q. My Autocirc makes a loud noise when it
shuts off.
A. What you are probably hearing is water hammer
that is caused when the pump shuts off and the valve
inside the housing of the pump closes. To correct this
problem you will need to install water hammer arrestors
on the hot and cold supply line near the pump. NOTE: a
new Autocirc check valve may be required if the
arrestors do not reduce this hammer.
Q. Since installing the Autocirc 303, water
flow and pressure from my hot/cold (or both) water
faucets above the pump is reduced or stopped
completely.
A. If you are using flexible hoses, make sure
that they are not kinked. If you are using either a
solid plastic or metal riser tubing (nut and ferrule
design) make sure that you have not inserted the tubes
too far down into the ports (3/8” compression) on
the top of the pump. Tubing inserted farther than 3/8”
into the housing tip ports can restrict/stop water flow.
Q. I am still not getting any flow from either
the hot or cold faucets since installing my Autocirc.
A. More than likely you dislodged some mineral
deposits when installing the Autocirc and they are now
clogging the aerator on your faucet. Remove the aerator
and clean any debris that is present.
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