Lochinvar 399 - 800 Noisy, No Pump, Operation Boiler Pump, System Pump, DHW Pump, Relief Valve

FAULT

CAUSE

CORRECTIVE ACTION

- Supply gas problem. Natural gas pressures

• Refer to Section 7 - Gas Connections of the Knight

should be between 4 inches w.c. (1.0 kPa)

XL Installation and Operation Manual for detailed

and 14 inches w.c. (3.5 kPa). LP gas

information concerning the gas supply.

pressures should be between 8 inches w.c.

(2.0 kPa) and 14 inches w.c. (3.2 kPa).

- Gas/air mixture problem.

• Refer to the Gas Valve Adjustment Procedure

on

page 41 of this manual for the proper gas valve setting.

Verify that the vent/air intake lengths do not exceed the

maximum listed in the General Venting section of the

Knight XL Installation and Operation Manual.

Noisy

- Dirty/damaged burner.

• Refer to page 26 in this manual for the burner removal

and inspection procedure. Clean or replace the burner

Operation

as necessary.

- Low water flow through the heat exchanger.

• Refer

to

Section

6 - Hydronic Piping

of

the

Knight XL Installation and Operation Manual for

minimum flow rates. Verify that the boiler is piped in a

primary/secondary fashion and that the boiler and

system pump are running on a call for heat.

- Air in the piping system.

• Properly purge all air from the piping system.

- Low system water pressure.

• Verify system pressure is a minimum of

12

psi

(82.7 kPa).

No Pump

- Blown fuse.

• Replace fuse F5 on the control board, see page 28 of

this manual.

Operation -

Boiler Pump

- Faulty pump.

• Replace pump.

System Pump

or

- Internal fault on control board.

DHW Pump

• Replace main control board.

- Faulty pump relay.

• Replace relay.

- System pressure exceeds relief valve

• Lower

the

system

pressure below the

50

psi

Relief Valve

setting.

(344.7 kPa) rating of the supplied relief valve or replace

the standard relief valve with a higher rated valve up to

Opening

the maximum pressure of the heat exchanger.

• Improperly sized expansion tank.