Blakeslee Conveyor Dishwasher Error Code B5: Boiler 1 Overtemperature
B5 BOILER 1 OVERTEMPERATURE means boiler 1 has exceeded its allowed temperature. The manual says to turn off the appliance and contact Technical Service. Let it cool, and have a service technician inspect the heater control.
High: an over-temperature boiler is a safety condition and the machine must stay off.
- Code
- B5
- Maker
- Blakeslee
- Equipment
- Conveyor dish machines
- Applies to
- RC-series rack conveyor with scrolling-text display and LED bar
What does Blakeslee error code B5 mean?
A boiler that overheats can scald and damage the machine, so the control watches boiler 1 against an upper limit. If the reading goes above it, the control removes power from the heater and displays B5 BOILER 1 OVERTEMPERATURE. The manual describes this as boiler 1 over-temperature and says to turn off the appliance and contact Technical Service, without any reset step. The usual causes are a heater contactor that has stuck, a probe that reads low and leaves the heater on, or a boiler running short of water. The alarm is the high side of the same circuit that reports B3 when the boiler does not warm up. The control stops the machine, because continuing to heat a boiler that is already over limit risks a pressure and scald hazard.
Affected models and control systems
Blakeslee RC-series rack conveyor dishwasher. The PDF is Blakeslee's RC44 User Manual and prints no model name; the same alarm list appears in the RC62 manual.
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
- B5 BOILER 1 OVERTEMPERATURE on the display
- Steam or hissing near the boiler
- Rinse water scalding hot
- Machine stops and stays off
Possible causes
Likely causes — what usually sits behind error code B5 on this control. A technician confirms which one it is before any part is replaced.
- Heater contactor stuck closed
- Boiler 1 probe reading lower than actual temperature
- Boiler running low on water
- Control output not switching the heater off
Safe checks before calling for service
- Turn the appliance off, as the manual instructs, and switch off the wall disconnect.
- Keep away from the boiler and let the machine cool.
- Do not restart the machine to test it.
- Check that nothing is leaking and the floor is dry.
- Note the display text and any steam, hissing or odor.
How a technician diagnoses error code B5
- Read the alarm history and note whether B2 or a fill problem came first.
- With power locked out, inspect the heater contactor for welded contacts.
- Compare the boiler probe reading with a reference thermometer.
- Confirm the boiler fills and holds level and check for leaks.
- Test the element and safety devices, then replace the confirmed part.
- An overheated boiler holds scalding water and steam under pressure.
- A stuck contactor is a line-voltage defect found only with the supply locked out.
- Distinguishing a bad probe from a bad control output requires meters and a reference thermometer.
How error code B5 differs from similar codes
B5 is boiler 1 running too hot. B3 is the opposite, where boiler 1 does not heat.
Technical reference
- Maker documentation
- Blakeslee owner support
- Edition
- COD. 4950E_U_USA, Ed. 00 - 09/2016
- Models / control
- RC-series rack conveyor with scrolling-text display and LED bar
- Section
- Chapter 12.2.1 Alarms description (pp. 54-55)
- 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 conveyor dish machine error codes
Is B5 a safety alarm?
Yes. The manual says to turn the appliance off, because a boiler over its limit is a scald risk.
Can I reset and carry on?
No. If the cause is a heater that cannot switch off, it will overheat again.
Does B5 mean the probe is wrong?
It can. A probe that reads too low lets the boiler run hot, so the probe is tested too.
Need help with Blakeslee error code B5?
A technician confirms the cause on site and gives you the price in writing before any work starts.