Blakeslee Commercial Dishwasher Error Code B3: Boiler Heating Alarm
B3 BOILER HEAT. ALARM is the manual's boiler heating alarm for the rinse boiler. The manual says to contact Technical Service, so a service technician should check the heating circuit.
High: the rinse boiler cannot heat, so the machine cannot complete a proper rinse.
- Code
- B3
- Maker
- Blakeslee
- Equipment
- Dish machines
- Applies to
- D-18D / D-18V digital-control door-type
What does Blakeslee error code B3 mean?
After the rinse boiler is filled, the control switches on its heater and watches the boiler temperature rise. If the temperature does not climb the way the control expects within its allowed time, the control assumes the heating has failed and raises the heating alarm. The display text is B3 BOILER HEAT. ALARM, abbreviated to fit the screen. The manual gives no more detail than calling it a boiler heating alarm and directs the operator to Technical Service, which suits the situation: the cause can be the heating element, the relay that switches it, a safety device that has opened or the supply to the machine. From the operator's side, the visible result is rinse water that never gets hot. The alarm is different from B2, which names the probe itself, and from B5, which reports a boiler that has become too hot rather than too cold.
Affected models and control systems
Blakeslee D-18D / D-18V digital-control hood-type dishwasher. The manual's cover prints D-19 L and D-19 LRS and names no D-18 model, so the alarm list is read as covering this hood-type family.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- B3 BOILER HEAT. ALARM on the display
- Final rinse water stays cold or lukewarm
- Cycle takes much longer than normal
- Dishes come out wet or not sanitized
Possible causes
Likely causes — what usually sits behind error code B3 on this control. A technician confirms which one it is before any part is replaced.
- Rinse boiler heating element burned out
- Contactor or relay that switches the element not closing
- Boiler safety thermostat tripped open
- One phase missing at the machine's electrical supply
Safe checks before calling for service
- Check that the machine's wall disconnect or breaker is on, and that nearby equipment has not lost power.
- Switch the machine off and on once and see whether the alarm returns.
- Do not start more cycles if the rinse is cold; dishes will not be properly sanitized.
- Do not open the boiler area, which is hot and live.
- Note how long the machine ran before the alarm and whether the wash tank heated normally.
How a technician diagnoses error code B3
- Read the alarm record and confirm B3 is not paired with a probe alarm.
- Measure supply voltage at the machine on all phases under load.
- Check the heating element for continuity and for insulation to ground, with power locked out.
- Test the heater contactor coil and contacts and any safety thermostat in the boiler circuit.
- Verify the boiler probe reads correctly before condemning the element, then replace the failed part.
- Heating circuits run at 208 to 240 volts or higher, and tests are made on live wiring.
- The boiler stays scalding hot, so working on it is a burn risk.
- Choosing between element, relay, thermostat and supply needs a meter and the machine's wiring diagram.
How error code B3 differs from similar codes
B3 is a heating failure of the rinse boiler. The wash tank has its own matching alarm, E3.
Technical reference
- Maker documentation
- Blakeslee owner support
- Edition
- COD. 3100ET_U, Ed. 06 - 09/2018
- Models / control
- D-18D / D-18V digital-control door-type
- Section
- Chapter 8.2 Alarms, table 3 (p. 39)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Blakeslee dish machine error codes
Why is my rinse water cold with B3 showing?
The boiler heater is not warming the water, so the final rinse does not reach its working temperature.
Is it safe to wash with only the wash tank hot?
The machine will not give a reliable hot rinse. Stop and arrange service.
Could a breaker cause this?
Yes, a tripped breaker or lost phase can look like a heating failure. Check the wall disconnect, then call if the alarm remains.
Need help with Blakeslee error code B3?
A technician confirms the cause on site and gives you the price in writing before any work starts.