Navien CH-180 Service manual - page 112
110
Check method
Error type
Cause
Check method
Remark
Check if the space heating strainer is clogged with
debris.
Check the cause of debris if the space heating
strainer is clogged.
(Aluminum distributor oxidized steel, etc.)
Low circulation due to defective circulation pump
impeller
Low circulation pump RPM
Replace the pump
Check if the distributor room valve is open.
Low heating circulation flow as the distributor or aged
pipe is clogged.
If only 1 valve of the distributor is open, heating is
delayed or is not done due to low circulation of space
heating water.
If heating is not done evenly, adjust the distributor valves
to make the circulation even.
Heating is not done due to defective supply thermistor or
return thermistor.
If the temperature is sensed higher than the actual
temperature, replace the thermistor.
Continuous heating is not provided due to 5-min waiting
function when there is small leakage from DHW pipe.
Water flow is detected according to the change of direct
water pressure.
Continuous heating may not be provided due to
5-min waiting function when water flow is detected at
the site where a direct water pressurizing pump is
used.
Remove the water flow sensor connector, operate the
heating function, and check if temperature changes.
Normal if the water flow value is “00” when the boiler is
not operating.
When hot water flows in the heating line as the 3-way
valve is not switched to heating for preheating for hot
water or due to defective packing.
Replace the 3-way valve.
Combus-
tion
ON/OFF
is
repeated
if the
heating
circula-
tion flow
is low.
No space
heating,
while the
boiler runs
No
combus-
tion of
boiler
Warm floor
when
heating
function is
not used.
The space
heating
strainer is
clogged.
Defective
circulation
in distribu-
tor and pipe
Defective
circulation
pump
Defective
thermistor
Detect DHW
flow
Defective
3-way valve
©Navien America Inc. 2010
CH series service Manual
Version 1.0