beautypg.com

Troubleshooting flowchart – John Wood Commercial - AJWS User Manual

Page 22

background image

TROUBLESHOOTING FLOWCHART

22

High water temp.

Will ECO light

reset once temp.

in t

ank cools?

Check continuity

across ECO.

Replace

ECO.

No hot water

.

Power to heater?

Is ECO light “ON”?

Go to next p

age.

Rep

air

power

problem.

When thermost

at

is turned up does

pilot sp

ark?

Check for 24V

between purple &

white wires on the

ignition control

module (ICM).

Is ground good

from ICM to

incoming ground?

Check for 24V

between PV &

PV/MV terminals

on gas valve.

Does pilot light?

Rep

air

ground.

Replace

gas valve.

Does sp

arking

stop?

Check for 24V

between PV

&

MV/PV terminals

on ICM

Check for 24V

between orange &

white wires on

damper harness.

Check for 24V

between PV

&

MV/PV terminals

on ICM.

Clean flame

sensor - check

ground.

Replace

ICM.

Check sp

ark wire

for damage & con-

tinuity

. Check

sp

ark ass’y for

cracks in ceramic

or wrong gap.

Byp

ass

damper

,

orange & purple

wires. If heater

fires, then replace

damper

.

Replace

ICM.

Bad

sp

ark ass’y

or wiring

between sp

ark

ass’y and

ICM.

Replace

faulty

p

art

s.

Replace

ICM

Go to next p

age.

Check gas supply

.

Rep

air

gas supply

.

All should

be OK.

Is there 24V

between MV &

MV/PV terminals

at the ICM?

Does main burner

st

ay lit until ther-

most

at satisfies?

Check for block-

age in burner or

orifice. Also

check

incoming gas sup-

ply

.

Does main burner

fire?

Is there 24V

between PV &

PV/MV terminals

at gas valve?

Replace

ICM.

Replace

gas valve.

Check and

adjust gas

pressure.

Go to next p

age.

Does pilot light

shrink or go out

when main burner

fires?

Is gas flex being

used, or other

small gas pipe?

Open

Closed

All OK

Found

damage

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

OK

Y

Y

Y

Y

OK

OK

N

This manual is related to the following products: