POWER VTX
®
WATER HEATER
34
PV500-68 06/16
11.3 Replacing the Fuse
The 24 VAC input and output circuits of the PIM are protected by a 2.0 Amp fuse.
11.4 Self-Check / Control Failure
The PIM confirms the integrity of the gas valve relay contacts to insure safety. It also monitors the processor
memory and software execution for proper program flow. If the control detects an error in its software or hardware,
all outputs are turned off and the LED displays a steady ON condition. If this condition persists after an attempt to
restart then the control must be replaced.
11.5 System Safety Checks
The PIM monitors the safety switches, temperature sensors, supply voltage, and blower speed and will go to soft
lockout until the error condition is corrected. Individual LED diagnostic codes or messages on the RS485
communications help identify the problem for efficient troubleshooting.
VENT MAX
The vent temperature sensor is used to protect low temperature
vent systems from damage caused by high flue gas temperatures.
When this alarm occurs, first confirm that the vent material is
suitable for the application as well as the limit setting for this control.
When this product is operated with high return or inlet water
temperature, the flue gas can exceed the rating of low temperature
vent systems.
6 17
HTR MAX
The heater high limit temperature safety has exceeded its limit. This
condition may be caused by a sensor failure or a faulty control
board.
7 18
HTR TOP
Indicates a problem with the top temperature sensor, possibly a
broken or shorted sensor wire or failed sensor.
NOTE:
The top
sensor and the high limit sensor or located in the same probe body.
8 11
HI LIMIT
Indicates a problem with the high limit temperature sensor, possibly
a broken or shorted sensor wire or failed sensor.
NOTE:
The top
sensor and the high limit sensor or located in the same probe body.
8 14
HTR BOT
Indicates a problem with the bottom temperature sensor, possibly a
broken or shorted sensor wire or failed sensor.
8 12
VENT
Indicates a problem with the vent temperature sensor, possibly a
broken or shorted sensor wire or failed sensor.
8 13
LOGASPRES
FAIL
The low gas pressure safety switch (optional) is not sensing the
minimum gas pressure required for safe burner operation. Check
the gas pressure to ensure that the minimum is available. If the gas
pressure is adequate check for fluctuating gas pressure or a faulty
pressure switch.
9 10
REM PROV
FAIL
The remote proving circuit, when used, is designed to check for the
operation of ancillary mechanical room equipment such as a fresh
air damper or flow switch. Check for the proper function and correct
wiring of such equipment.
10 8
LOW WATER
FAIL
The electronic low water cutoff is no longer sensing water at its
probe. This could also be cause by a faulty low water board or
sensor
12 7
HTR LOST
This could be caused by a poor connection between the PIM control
and the digital control display or failure of either device.
14 6
HIGASPRES
Check the gas pressure to ensure that the building supply doesn’t
exceed the value on the heater rating plate. If the gas pressure is
within rated limit, check for a faulty pressure switch.
15 26
