Ventilators

Hamilton Medical G5: troubleshooting and error codes

The ServiceForge knowledge base holds 36 documented symptoms for the Hamilton Medical G5, with 38 ranked causes, 77 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Auxiliary Rinse Flow improper operation

Bubbles present in Auxiliary Rinse Flow tube when none should be present, or absence of expected bubbles in configured systems

Ranked causes

1. Metal Plate position incorrect (common)
2. Leaks in Auxiliary Rinse Flow system (occasional)

First check

Verify Auxiliary Rinse Flow tube response in water

Test point: Paux connector
Expected: No bubbles present (unless specifically configured for Auxiliary Pressure Measurements)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Flow Sensor Autozero Valve malfunction

dP Flow Sensor pressure does not alternate between zero and ~5000 μbar in five-second intervals when one connector is sealed

Ranked causes

1. Autozero Valves not opening and closing properly (unknown)
2. Rinse flow circuit blockage or malfunction (unknown)

First check

Verify silver Flow Sensor connector pressure alternation

Test point: Silver Flow Sensor connector
Expected: Alternates every 5 seconds between -40 to 40 μbar and 5040 to 5200 μbar, ±40 to 5200 μbar range

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

100% O2 Button does not change color

100% O2 Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

100% O2 Button color change

Test point: 100% O2 Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

A/D Converter channels read out of range

A/D converter test unit displays voltage readings outside specified ranges for power supply monitoring channels

Ranked causes

1. 15 VDC power supply voltage out of tolerance (unknown)

First check

A/D Channel 11 (15 VDC supply monitor) reading

Test point: Test Unit screen ADC 11
Expected: 7250 to 7750
Tools: Ventilator test mode display

4 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm Silence Button does not change color

Alarm Silence Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

Alarm Silence Button color change

Test point: Alarm Silence Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Ambient valve does not close patient safety

Patient can inhale and exhale through bacteria filter when valve should be closed

Ranked causes

1. Ambient valve stuck open or control failure (unknown)

First check

Verify valve closes when commanded

Test point: Patient breathing circuit at bacteria filter
Expected: Inhalation not possible through patient tubing

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Ambient valve does not open patient safety

Patient cannot inhale through bacteria filter; ambient valve remains closed when it should be open

Ranked causes

1. Ambient valve stuck or malfunctioning (unknown)

First check

Verify ambient valve can open

Test point: Patient breathing circuit at bacteria filter
Expected: Free inhalation possible, Ppat in range 0 to -20 mbar, 0 to -20 mbar

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blue Alarm Lamp does not dim

Blue Alarm Lamp brightness does not respond to dimming control via P&T Knob or does not switch off when deselected

Ranked causes

1. Alarm Lamp LED or dimming circuit malfunction (unknown)

First check

Blue Alarm Lamp dimming response

Test point: Blue Alarm Lamp on Front Panel
Expected: lamp dims when P&T Knob rotated

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Complete Inspiratory Valve Check Unit

Final step to close Inspiratory Valve Check Unit after all tests and checks completed; record results on Test Report

Ranked causes

1. Inspiratory Valve Check Unit completion (common)

First check

Document all test results on Test Report form

Test point: Test Report documentation
Expected: All measured values and pass/fail status recorded

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Flow Sensor

Flow Sensor calibration performed in Adult Mode with Patient Breathing Circuit; sensor must be removed, turned, and replaced as instructed on screen

Ranked causes

1. Flow Sensor requires calibration (common)

First check

Verify calibration completion status on screen

Test point: Cal. status field
Expected: Flow Sensor is calibrated message displayed; Cal. status = 0

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Inspiratory Valve air delivery at 20 ml/s

Servo Valve delivery flow and pressure adjustment using 20 ml/s Capillary Tube; performed in Adult Mode

Ranked causes

1. Servo Valve 20 ml/s potentiometer requires adjustment (common)

First check

Measure pressure at inspiratory valve output with 20 ml/s flow

Test point: To patient port with 20 ml/s Capillary Tube connected
Expected: Pressure marked on Capillary Tube ±3 mbar, ±3 mbar
Tools: Pressure Gauge, 20 ml/s Capillary Tube

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Inspiratory Valve air delivery at 500 ml/s

Servo Valve delivery flow and pressure adjustment using 500 ml/s Orifice Tube with altitude correction; performed in Adult Mode

Ranked causes

1. Servo Valve 500 ml/s potentiometer requires adjustment (common)

First check

Determine altitude correction factor from Table 8-3

Test point: Operating location altitude in meters above mean sea level
Expected: Correction value from altitude table (range -8.4 to +4.3 mbar)
Tools: Altitude table (Table 8-3)

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Inspiratory Valve linearity at multiple flow rates

Verify Inspiratory Valve delivers correct flow and patient pressure across range of 20–1000 ml/s flows; do not use 2000 or 3000 ml/s buttons (peak flow only)

Ranked causes

1. Inspiratory Valve flow and pressure linearity requires verification (common)

First check

Measure Flow pat (flow to patient) at 20 ml/s setting

Test point: Inspiratory Valve output, Flow pat field
Expected: 0 to 40 ml/s, 0–40 ml/s

18 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Mixer gain and pressure

Adjustment of mixer maximum tank pressure and oxygen concentration delivery during gas-inlet/gas-use cycle

Ranked causes

1. Mixer requires full-scale calibration (common)

First check

Verify tank maximum pressure after calibration

Test point: Ptank max
Expected: 330 to 350 mbar, 330-350 mbar

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: O2 Cell

Calibrate oxygen cell measurement linearity at 100%, 50%, 21% and 0% oxygen concentrations

Ranked causes

1. O2 cell requires calibration (common)

First check

Cell preparation and storage condition

Test point: O2 cell temperature
Expected: Room temperature (if refrigerated, wait 30 minutes minimum)

4 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Oxygen concentration

Verification that mixer delivers correct oxygen concentration matching knob setting

Ranked causes

1. Oxygen concentration delivery requires verification (common)

First check

Verify oxygen concentration matches knob setting

Test point: Oxygen field display vs Oxygen knob setting
Expected: Same as knob ±5%, ±5%

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Control Knob does not respond to rotation

P&T Knob turn encoder not registering movement or digital count does not match physical rotation

Ranked causes

1. Control Knob encoder malfunction (unknown)

First check

P&T Knob right rotation digital count

Test point: Control Knob LCD display
Expected: positive count matching 16 physical clicks

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Front Panel Hard Keys Color LEDs do not dim

Color LEDs on Hard Keys do not respond to dimming control or do not return to original brightness when deselected

Ranked causes

1. Hard Key LED circuit or dimming control malfunction (unknown)

First check

Color LED dimming response

Test point: Color LEDs on Front Panel Hard Keys
Expected: LEDs dim when P&T Knob rotated

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Front Panel Hard Keys White LEDs do not dim

White LEDs on Hard Keys do not respond to dimming control or do not return to original brightness when deselected

Ranked causes

1. Hard Key LED circuit or dimming control malfunction (unknown)

First check

White LED dimming response

Test point: White LEDs on Front Panel Hard Keys
Expected: LEDs dim when P&T Knob rotated

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

High alarm tone not audible caution

High audible alarm tone not playing through IPP Speaker

Ranked causes

1. IPP Speaker malfunction (unknown)

First check

High alarm audible output

Test point: IPP Speaker
Expected: 3 tones followed by 2 tones, continuously repeating

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

LCD Display does not dim or brighten

LCD Display brightness does not respond to dimming control or does not return to original brightness when deselected

Ranked causes

1. LCD brightness control circuit malfunction (unknown)

First check

LCD Display dim function

Test point: LCD Display on Front Panel
Expected: display dims when brightness button selected

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low alarm tone not audible caution

Low audible alarm tone not playing through IPP Speaker

Ranked causes

1. IPP Speaker malfunction (unknown)

First check

Low alarm audible output

Test point: IPP Speaker
Expected: two tones, not repeated

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Manual Breath Button does not change color

Manual Breath Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

Manual Breath Button color change

Test point: Manual Breath Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Medium alarm tone not audible caution

Medium audible alarm tone not playing through IPP Speaker at correct intervals

Ranked causes

1. IPP Speaker malfunction (unknown)

First check

Medium alarm audible output and interval timing

Test point: IPP Speaker
Expected: 3 tones repeated after 25 seconds, then every 30 seconds

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Mixer valve leakage check

Verification of mixer valve closure and combined leakage flow measurements at two time points

Ranked causes

1. Mixer valves may have excessive leakage (occasional)

First check

Verify 90ms mixer valve leakage flow

Test point: 90ms flow
Expected: 0 to 300 ml/s, 0-300 ml/s

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Nebulizer On/Off Button does not change color

Nebulizer On/Off Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

Nebulizer On/Off Button color change

Test point: Nebulizer On/Off Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Patient overpressure valve does not open patient safety

Valve fails to open or opens outside specified pressure range during overpressure simulation

Ranked causes

1. Patient overpressure valve malfunction (unknown)

First check

Simulate overpressure by pumping hand pump

Test point: Patient tube pressure
Expected: Valve opens and pressure drops between 104 and 116 mbar, 104 to 116 mbar

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Print Screen Button does not change color

Print Screen Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

Print Screen Button color change

Test point: Print Screen Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Red Alarm Lamp does not dim

Red Alarm Lamp brightness does not respond to dimming control via P&T Knob or does not switch off when deselected

Ranked causes

1. Alarm Lamp LED or dimming circuit malfunction (unknown)

First check

Red Alarm Lamp dimming response

Test point: Red Alarm Lamp on Front Panel
Expected: lamp dims when P&T Knob rotated

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Safety valve block leakage

Pressure drop rate exceeds acceptable threshold during tightness check

Ranked causes

1. Safety valve block leaking (unknown)

First check

Generate pressure with hand pump

Test point: Patient tube
Expected: 90 mbar

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Servo valve leakage

Pressure gauge reading exceeds acceptable limit during servo valve tightness check

Ranked causes

1. Servo valve leaking (unknown)

First check

Measure pressure during servo valve tightness test

Test point: Pressure gauge
Expected: less than 4 mbar, <4 mbar

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Standby Button does not change color

Standby Button on Interaction Panel not responding or not changing color when pressed

Ranked causes

1. Interaction Panel button or LED malfunction (unknown)

First check

Standby Button color change

Test point: Standby Button on Interaction Panel
Expected: button changes color when pressed

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Tank overpressure relief valve check caution

Verification that tank overpressure relief valve opens at correct pressure when tank is pressurized with oxygen

Ranked causes

1. Tank overpressure relief valve may not open at correct pressure (occasional)

First check

Measure tank pressure at overpressure valve opening

Test point: Ptank
Expected: Less than 500 mbar, <500 mbar

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Tank tightness check

Verification of tank seal integrity by measuring pressure decay rate

Ranked causes

1. Tank may have leakage (occasional)

First check

Measure tank pressure decay time

Test point: Ptank
Expected: Pressure drop from 300 to 280 mbar takes more than 8 seconds, >8 seconds

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unequal rinse flow through Flow Sensor connectors

Air bubble rates differ between silver and blue Flow Sensor connectors when tested with equal-length tubes in water

Ranked causes

1. Rinse flow restriction or blockage in one channel (unknown)

First check

Verify equal rinse flow through both Flow Sensor connectors

Test point: Silver and blue Flow Sensor connectors
Expected: Number of air bubbles appears equal on both sides

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Yellow Alarm Lamp does not dim

Yellow Alarm Lamp brightness does not respond to dimming control via P&T Knob or does not switch off when deselected

Ranked causes

1. Alarm Lamp LED or dimming circuit malfunction (unknown)

First check

Yellow Alarm Lamp dimming response

Test point: Yellow Alarm Lamp on Front Panel
Expected: lamp dims when P&T Knob rotated

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.