TROUBLESHOOTING GUIDE
Leaks between bottom of housing and cap
1. Ensure sump is tightly screwed to cap. If it still leaks close
the cold water supply and tank valves.
2. Clean black rubber O-ring and lubricate with clean silicone
grease. With two fingers, insert O-ring in groove below
threads of housing and press into place. Tighten housing
back onto cap.
3. Open the cold water supply and tank valve.
If leaks persist, call Technical Support.
Leaks on tank valve assembly
1. Open drinking water faucet to drain storage tank. Let
drinking water faucet run until it drips. Turn off cold water
supply.
2. Push in on white collar of tank valve fitting and pull out
tubing. Unscrew the tank valve from the storage tank.
Rewrap threads on top of the tank with plumber tape. Screw
tank valve back onto tank. Trim 1/2-inch from end of tubing
and reinsert 5/8-inch into tank valve fitting.
3. Open the cold water supply and shut off the reverse osmosis
faucet. Let the system pressurize for several hours and
check for leaks. Check again after tank is fully pressurized.
Leaks on quick-connect fittings
1. Close the cold water supply and tank valve.
2. Depress plastic collar and pull out tubing.
3. Cut off 1 inch of tubing and place a mark 5/8-inch from end
of tubing. Tubing should be cut squarely. The internal and
external burrs should be removed.
4. Push tubing 5/8-inch into fitting.
5. Open the cold water supply and tank valve. If leaks persist,
call Technical Support.
No flow or slow flow from the brine (drain) line
Less than 1½ cups per minute
NOTE: Before checking brine (or reject) flow, make sure the
system is producing water by turning off the valve on the
storage tank and opening the faucet. Water should drip
from faucet.
1. Examine the pre-filters. If clogged, replace (see Replacing
the Pre-Filters and Post-Filter on page 10) and recheck the
brine (or reject) flow rate.
2. If the pre-filters are not at fault, the brine (or drain) flow
controller is probably clogged. Call Technical Support.
High TDS in Product Water
If high levels of TDS (Total Dissolved Solids) are detected in
your product water (approximately 30% or greater of what is
measured in your tap water, as determined with a conductivity
meter or by the supplied TDS Test Kit), the GRO membrane
element may need to be replaced, or the brine (or drain) flow
control tubing may be clogged. See your dealer or plumber to
check product water TDS.
Reduced production
Slow or no product water flow usually indicates either a
clogged pre-filter or an exhausted membrane. First, replace
the pre-filters. If the production rate is not improved, replace
membrane.
12 • GRO-2550 Installation and Operation Manual
Gradual return of taste and odor
Gradual return of unpleasant taste and odor over a period
of time may indicate that your filter cartridges and/or RO
membrane need to be replaced. See Replacing the Pre-Filters
on page 10 and Replacing the Reverse Osmosis Membrane"on
page 11.
Sudden return of taste and odor
If shortly after complete servicing noticeable taste and odors
return contact Technical Support.
No water pressure from the drinking water faucet
or low volume in storage tank
1. Close the cold water supply to system.
2. Lift storage tank to see if it is empty. If not, open the drinking
water faucet to empty water from tank.
NOTE: It may be necessary to pump a small amount of air into
the tank with a bicycle pump to remove all the water
from the tank.
3. When tank is empty, use a pressure gauge to check
tank pressure. An empty tank should contain 5 to 7 psi
pressure. Increase or decrease the air pressure in the tank
accordingly.
4. Open cold water supply. Let system run for 3 hours to fill
tank, then check system performance. If performance has
not improved, call Technical Support.