Graco 309524L User Manual

Heater will not heat.

No current.

Check circuit and fuses.

Check continuity of primary thermo-
stat (24), backup thermostat (10), 
and thermal limit sensor (15).

Check continuity of thermostat (10) 
and heater block (3) terminals - Page 
18.

Burned out heater block (3).

Replace block - Page 20.

Blown heat limiter (15).

Check continuity of primary thermo-
stat (24) and backup thermostat (10). 
Replace thermostats if necessary 
when replacing thermal limit sensor 
(15) - Pages 18-20.

Temperature too low.

Fluid requires more warm-up time.

Increase warm-up time.

Wrong temperature setting.

Adjust setting - Page 15.

Flow rate too high.

Reduce flow rate or use 2 heaters.

Clogged fluid passages.

Flush regularly - Page 16.

Temperature too high.

Wrong temperature setting.

Adjust setting - Page 15.

Failed primary thermostat (24).

Replace - Page 18.

High fluctuating temperatures, about 
220-250°F (104-120°C) at 0.1 GPM.

Primary thermostat (24) contacts 
sticking.

Replace thermostats (24, 10) - Page 
18. Note that backup thermostat (10) 
keeps heater functioning for only a 
short time.

Too much pressure drop or fluid will 
not flow.

Flow rate too high.

Reduce flow rate or use 2 heaters.

Clogged fluid passages.

Flush regularly - Page 16.

Heater fittings leak.

Loose or damaged fittings.

Tighten fittings or replace heater 
block - Page 20.

F

R

300°F

230°F

255°F

(110°C)

a

1

e

2

(149°C)

(124°C)

e

1

SL

Mp

R

6-55 ohm

05556-524