MPI KWH124 - Water Flow and Temperature Diagnostics; Interpreting Error Codes and Normal Conditions

(5) Water does not flow from hot water outlet.
Water supply valve at Main is not
open.
Open Water Supply Valve at Main.
(6) Hot Water temperature is too low.
>(c Temperature adjustment is set too low.
:fc Hot Water is being used beyond capa-
city.
% Water and/or debris get in Fuel Filter-
/Fuel supply pipe.
Set Temperatrue Adjustment higher.
Partially close the Hot Water outlet.
Clean, or replace.
(7) Hot Water temperature is too hot.
Set Temperature Adjustment is set on
high.
Set Temperature Adjustment lower.
(8) Unit goes into the state of code "4" occasionally.
(Unit is shut off.)
Water and/or debris get into Fuel
Filter/Fuel supply pipe.
Air remains in Fuel Supply pipe.
Clean, or replace.
Purge air from Fuel Supply Pipe.
Refer to page 5.
The following are conditions that are normal or easily remedied :
§ OPENING HOT WATER SUPPLY VALVE A SMALL AMOUNT WON'T START UNIT :
The burner of this unit cannot be ignited unless minimum water flow about 0.45 G/min is
maintained. Open up faucet wider.
§ HOT WATER TEMPERATURES CAN VARY WITH MULTIPLE FAUCETS OPEN :
When hot water is used from two or more faucets simultaneously, the amount and
temperature of hot water from each faucet could vary depending on piping scheme and how
much each valve is opened. This tendency could be enhanced when shower and another
faucet are put to service simultaneously.
§ HOT WATER APEARS OPAQUE :
Hot water might look white and opaque during initial outflow, because air mixes with
water in heater, and under pressure is released to atmosphere when faucet is opened.
When this happens, air and water come out in the form of bubbles, looking white. There is
no harm in this process, and hot water will soon turn transparent.
| SOUND OF FAN MOTOR STILL AUDIBLE AFTER UNIT IS TURNED OFF :
Fan motor continues to run for about 150 seconds after unit is turned off in order to drive
exhaust gas out of combustion chamber.
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