Operating instructions

Part number 550-141-887/0800
41
AHE Series 4 Direct Vent Wall-Mounted Boilers — Boiler Manual
Troubleshooting — charts continued 12d
CHART 8 — Insufficient heat or no heat to system (POWER light on steady)
Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow
instructions could result in severe personl injury, death or substantial property damage.
• Excessive block temperature has been reduced to safe
operating level. Check for low water level or mineral
deposits in sections. Correct before proceeding.
• Restart boiler and check normal sequence of operation.
(See normal sequence of operation, Figure 17, page 22.)
• Boiler is in standby.
• Set thermostat to call for heat
and recheck operation.
• Verify Sequence of operation,
Figure 17, page 22.
• Replace control module.
• Retest.
• Boiler water temperature exceeded setting on limit switch
with thermostat calling for heat. Boiler is OK. (See
normal sequence of operation, Figure 17, page 22.)
• Also check operation of setting on limit switch (should be
above 140˚F.).
• Has it been at least 5 minutes since setting thermostat to
call for heat? If not, wait 5 minutes. Is system heating?
• Is thermostat set to call for heat? Remove thermostat
wires at boiler and check continuity across the two wires.
If circuit isn't closed, check external thermostat (zone
valve, relay, etc.) wiring. Correct problems and retry.
• Reconnect external thermostat wiring at boiler.
Is thermostat circuit closed (continuity across wires)?
• If you have sufficient heat — boiler should be in normal
operating sequence. (See normal sequence of operation,
Figure 17, page 22.)
• If you have less than sufficient heat —
Is vent or combustion air piping free of blockage?
No Yes
• Correct conditions and
recheck operation.
• See Figure 17, page
22 for normal
sequence of operation.
Contact your Weil-McLain
sales representative.
• Replace control module.
• Retest.
• Repair/replace
circulator. Retest.
• Repair/replace wiring.
Retest.
• Remove CIRCULATOR harness plug from
CIRCULATOR plug receptacle (
Figure 29, page
34, Item 4
). Check with voltmeter across right-side
120 VAC N and 120 VAC H pins of receptacle.
Does voltmeter show 120 VAC across pins?
No Yes
Is boiler System circulator operating?
Wait 5 minutes.
Is FLAME light on?
No Yes
Wait for boiler water to cool to temperature 20 to 30 ˚F
lower than temperature set on limit switch.
Are limit switch contacts closed?
Check block switch on top of boiler with continuity checker.
Are block switch contacts closed?
No Yes
Are all red lights off?
No Yes
Wait 30 seconds.
Are all red lights off?
No Yes
Replace block
switch. Retest.
Replace control
module. Retest.
Check limit switch contacts
with continuity checker.
Are limit switch
contacts closed?
NoYes
Wait for cast iron block to
cool to room temperature.
Are block switch
contacts closed?
No
Yes
No Yes
No Yes
Replace limit
switch. Retest.
No Yes