Kenmore KWX - 5V, KWX - 9V, KWX - 8V, KWX - 3V, KWX - 6V Honeywell L7148F Trouble Shooting Guide

HONEYWELL L7148F TROUBLE SHOOTING GUIDE

Start

Boiler is cold.

Boiler is not reaching proper temperature or will not tum on.

4,

Check:

L7t 48F Diagnostic LED =ON"?

I

Yes

Set room thermostat lO°above room temperature.

Set boiler 10° (or more) above current

water temperature. Boiler turns on?

-- No--

/No ___

Check for 12BY at LIX, L2X.

Check for 24V at R C

I

on L7148.

BoilerShort terminalsstarts? W-R (T-TW)

I

No

÷

Turn power "ON".

Check all wiring connections.

Replace transformer as appropriate.

Thermostat cr Thermostat widng problem.

Check system per instructions provided with thermostat.

___

Two Blinks:

Check sensor connections. If good, replace sensor.

L7148F Diagnostic LED, flashing?

Check:

	Yes	_	Internal error,	replace L71 48F control.
_-_			Three or four	blinks:

I

Yes			No							I
i					Check for 24V,		at	81, B2?		I
			÷
					J			,		I
		Check:
					--			Yes
		L7148F in reset mode (wait 5 minutes						4,
		for control to	reset).
Check Circulator Pump, running?		Vent damper	apen?		L7148F is OK,		check ignition and gas
		]
I			t		valve system as described in literature
					provided with	those products
			No
Yes		No
		Check vent damper cable and		I_	t				ts it still set
		connections.			Check room	thermostat,				at
	I	Replace vent	damper cable or damper		10° above current			room	temperature?
Boiler shuts off at high limit setting?	I	as appropriate.			7'

_r

Yes

No	I	120vacatC1,C27		L	No
!		4,		/
		i
		Y_s
Boiler shuts off above high limit setting?		L7148F	is OK
		Check	other	system components:
		Circulators,		Zone Valves
t		Yes
No (Below	HL)	Check:
4,
		Temperature/Pressure			gauge
		accuracy
Check L7148F diagnostic	LED Flashing?	Sensor fully inserted			into well
		Thermo Well in good condition.
I		Thermo Well located per boiler OEM
		recommendations.

No

_tNo

Replace L7148F.

Control failure, incapable of self diagnostics.

_r

IReset thermostat and repeat voltage check

i

I

4,		Yes
Check:		Two blinks, replace	sensor,
Temperature/Pressure	gauge accuracy.	L_ Three or four blinks,	replace control.

Thermo Well tocated per boiler OEM instructions.

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