Filter
Top Products
6 720 606 518
Troubleshooting
21
water path, causing the water to over heat which shuts
all gas off to the heater. See chapter 5.6.1 for descaling
instructions.
8. If steps 1 through 7 do not correct the problem, then
confirm that the gas pressure is adequate. Ensure gas
pressure is in accordance with manufacturer's
specifications (see chapter 3.8). A gas pressure
reading is needed to proceed further. Contact your
original installer or a licensed gas technician to obtain
this reading.
6.5 Burners do not light with water
flow
1. Verify the pilot is lit
2. Verify the 3-flame button ( )is pushed in.
3. Verify the cold water supply is connected to the right
side of the heater.
4. Close installer supplied cold water shut off valve (if
none installed, install before proceeding). Open all hot
water taps supplied by the heater. Wait 5 minutes and
check all taps. Any water running is a sign of a plumbing
crossover. Consult a local plumber or service person for
help in correcting a plumbing crossover.
5. Verify flow through the water heater is sufficient. Fully
open a hot water faucet and fill a quart container. If the
container fills in 30 seconds or less, the flow rate (1/2
gallon per minute) is sufficient to activate the heater.
6. Inspect the water path outside of the heater for
obstructions. Make sure all showerheads, faucet
aerators and whole house filters are clear of debris.
Also, the water heater's inlet filter screen should be
inspected and cleaned (see chapter 5.2).
7. The water valve assembly, which actuates the
burners, requires periodic maintenance (every 2 - 5
years depending on water quality and use) (see
chapter 5.2).
6.6 Hot water temperature fluctuates
at tap
1. Close off installer supplied cold water shut off valve
(if none installed, install before proceeding). Open all
hot water taps supplied by the heater. Wait 5 minutes
and check all taps. Water running is a sign of a
plumbing cross-over. Consult a local plumber or service
person for help in correcting a plumbing crossover.
2. Check for a clogged inlet water filter screen (see
chapter 5.2).
3. Hot water is very hot out of the tap, requiring a lot of
cold water to be added with it in order to attain a
useable hot water temperature. The addition of too
much cold will overpower and slow the flow within the
tankless water heater, decreasing it below activation
point, which shuts off the burners. The end result is
nothing but cold water coming out of the outlet.
Recalibrate thermostat for cooler outlet temperatures.
(See chapter 4.4).
4. The GWH 1600 PS is designed to modulate gas
flow to the burners when water flow varies. If the water
pressure in the home is erratic and the water flow is not
consistent while a tap is opened, then the temperature
of hot water will fluctuate. The minimum water pressure
for the home should be 30psi or greater. For installation
on a private well system with the use of a pressure tank,
the lowest pressure range setting recommended is 30-
50 psi (2.07-3.45 bar). The use of a pressure reducing/
regulating valve before the water heater (directly after
pressure tank on well systems) is an effective way to
maintain constant water pressure to the water heater.
Watts brand 25AUB- ¾" or N35B-¾" pressure
reducing/regulating valves or equivalent are suggested.
5. A temperature balance shower valve can
automatically mix in cold water to reduce hot water
temperatures. This can slow the flow within the tankless
water heater, decreasing it below activation point,
which shuts off the burners. In the event of any
temperature instability with the use of a temperature
balance shower valve, refer to shower valve
manufacturer's instructions for internal adjustment
setting. An adjustment should be made to minimize the
amount of cold water the valve is adding.
6. The gas pressure also needs to be stable and
adequate. Ensure gas pressure is in accordance with
manufacturer's specifications (see chapter 3.8). A gas
pressure reading is needed to proceed further. Contact
your original installer or a local certified gas technician
to obtain this reading.
7. A water valve which has not been serviced may be
unable to keep the gas valve open. The water valve
requires periodic maintenance (every 2-5 yrs
depending on water quality and use) (see chapter 5.2)
6.7 Water is too hot
1. Verify gas type indicated in rating sticker located on
right-hand side of cover, coincides with the gas type
you are using. NG is a natural gas unit and LP is for
liquid propane.
2. Recalibrate thermostat for cooler outlet
temperatures. (See chapter 4.4).
3. Increase the flow rate. Restrictions in the water path
can slow the flow of water through the heater, resulting
in very hot outlet temperatures. Restrictive
showerheads and faucet aerators should be cleaned or
upgraded with less restrictive ones. In addition, the
water heater's inlet filter should be cleaned and
inspected (see chapter 5.2).
4. If the water has a high mineral content, the heat
exchanger may be scaled internally. This restricts the
water path, causing the water to boil and produce
extremely hot temperatures. See chapter 5.6.1 for
descaling instructions.