HTP 399M - Manual (Page 66)

66
When servicing or replacing parts that are in direct contact with boiler water, be certain that:

There is no pressure in the boiler. (Pull the release on the relief valve. Do not rely on the pressure gauge reading.)

The boiler water is not hot.

The electrical power is off.
DO NOT USE THIS BOILER IF ANY PART HAS BEEN SUBMERGED IN WATER. Immediately call a qualified service technician. The
boiler MUST BE replaced if it has been submerged. Attempting to operate an boiler that has been submerged could create numerous
harmful conditions, such as a potential gas leakage causing a fire and/or explosion, or the release of mold, bacteria, or other harmful
particulates into the air. Operating a previously submerged boiler could result in property damage, severe personal injury, or death.
NOTE: Boiler damage due to flood or submersion is considered an Act of God, and IS NOT covered under product warranty.
This boiler has wire function labels on all internal wiring. Observe the position of each wire before removing it. Wiring errors may cause
improper and dangerous operation. Verify proper operation after servicing.
Table 15
925 Control Board FAULT
Code Description Remedy
F00
High temperature switch limit
exceeded 194 o F
1. Check circulation pump operation.
2. Assure that there is adequate flow through the boiler by accessing the status menu and assuring that
there is less than a 50
o F rise from the return thermister to the supply thermister.
3. Check thermister reading on supply thermister. Replace switch if faulty.
4. If this is a new installation, disconnect the two light grey wires from the zone control, and twist the wires
together. Press
S4 . If the fault clears, the problem is outside the boiler.
5. If this is an existing installation with glycol, check the condition of the water pressure switch. It may be
necessary to jump out the water pressure switch (temporarily only, as a troubleshooting aid). The 24 VAC
signal may have grounded through the glycol if the water pressure switch is leaking.
F01
Vent temperature limit
exceeded
1. Push the red reset button on the vent temperature limit switch.
2. Check the flue temperature during operation using a combustion analyzer.
3. Replace the vent limit switch if faulty.
4. Verify the combustion drain is clear and draining properly.
5. Visually inspect the target wall and ensure it is intact. If not intact, replace the target wall.
If overheating occurs or the gas supply fails to shut off, do not turn off electrical power to the circulating pump. This may aggravate the
problem and increase the likelihood of boiler damage. Instead, shut off the gas supply to the boiler at the gas service valve.
925 CONTROL BOARD ERROR CODES
CODE DESCRIPTION DURATION CORRECTIVE ACTION
E001 High Limit Exceeded 50 Sec.
1. Check circulation pump operation.
2. Assure there is adequate flow through the boiler by accessing the status menu
and assuring there is less than a 50
o F rise from the return thermistor to the supply
thermistor.
3. Replace switch if faulty.
E131
Combustion Fan Speed Low.
The boiler combustion air fan
speed less than 70% of
expected.
60 Sec.
1. Check the combustion air fan wiring.
2. Replace the combustion air fan.
3. Replace the control board.
E14
Combustion Fan Speed High.
The boiler combustion air fan
speed is more than 130% of
expected.
60 Sec.
1. Check the combustion air fan wiring.
2. Replace the combustion air fan.
3. Replace the control board.
PRO Water Pressure Switch is
Open
Until Corrected
1. Assure that the system pressure is above 10 psig.
2. Check for leaks in the system piping.
FLU
Blocked Vent Pressure Switch
open
Until Corrected
1. Check the flue vent to be sure it is not blocked or damaged.
2. Check the blocked vent pressure switch operation by applying a jumper.
(If the switch is not functioning properly, replace it.
Do not “Jump Out” any of the devices in this circuit. These devices
ensure product safety and must be in place and connected at all times
of normal operation.