HVAC Classroom: Loma Wall-Mounted Boiler

概要： After domestic hot water use, three-way method: Standby time setting (Basic: 12 (120 seconds)) During domestic hot water use: Temporarily interrupt and adjust standby time (03 (30 seconds), 06 (60 seconds), 12 (120 seconds), 18 (180 seconds)) 04 -> Heating water temperature control switching to room temperature control: Set the difference between the set temperature and the ignition temperature (Basic: 1 degree -> Ignition temperature = Set temperature - 1 degree (1, 2, 3, 4) degrees, column) 2 degrees set -> Ignition temperature = Set temperature - 2 degrees, Reference) Extinguishing temperature = Set temperature + 1 degree

Luma wall-mounted boiler

A wall-mounted boiler fault code

Fault code:

Code:

Cause of fault: Ignition failure — displayed after three ignition attempts fail

Inspection items: Check the ignition wiring, gas valve, flame sensor, and whether the gas switch is turned on.

Code:

Cause of failure: Low water level – occurs when the water level in the tank is too low (applicable to open-type boilers).

Inspection items: inspect the automatic water refill valve and the water level sensor.

Code:

Cause of failure: Overheating – occurs when the heating or hot water temperature exceeds 95°C; resets after 15 minutes or when the temperature drops below 80°C.

Press the button again to cancel.

Inspection items: Check the circulation pump, filter screen, pressure relief valve, and external valves.

Code:

Fault cause: Fan at low speed – occurs when the speed falls below the reference value (the threshold varies by model).

Inspection items: Check the fan and the flue.

Code:

Cause of failure: Fan at high speed – occurs when the speed exceeds the baseline (speed varies by model)

Inspection items: Check the fan and the flue.

Code:

Cause of fault: Gas leak detected – applies only when a gas detector is installed.

Inspection items: Check for gas leaks in the gas pipes and verify the gas detector.

Code:

Cause of failure: Low water pressure – Occurs when the heating system water pressure falls below 0.3 bar.

Inspection items: Verify the pressure relief valve, open the make-up water valve to replenish water, and check for leaks.

Code:

Cause of failure: High water pressure – occurs when the heating system pressure exceeds 3.5 bar.

Inspection items: Check the pressure relief valve and the make-up water valve. Verify that the pressure relief valve is functioning properly.

Code:

Cause of failure: Heating temperature probe malfunction – occurs when the heating temperature probe is short-circuited.

Inspection item: Verify whether the heating temperature probe is functioning.

Code:

Cause of failure: Domestic hot water sensor malfunction – occurs when the domestic hot water sensor is short-circuited.

Inspection item: Verify whether the domestic hot water temperature sensor is functioning.

Code:

Cause of failure: Indoor thermostat malfunction – occurs when the indoor thermostat fails to operate or when there is a short circuit in the wiring.

Inspection item: Verify whether the indoor thermostat is damaged.

Code:

Cause of failure: Mismatched model selection – occurs when the model does not match the initial production model, causing operation to stop.

Inspection item: Verify that the boiler model matches the motherboard jumper settings.

Boiler operation

1) Set the heating water temperature

- Temperature setting range: 45–80°C

- Ignition temperature = Set temperature - (Storage temperature - User-defined holding temperature)

* Storage temperature varies depending on the set temperature.

* The default user-set temperature is 0. It can be adjusted using special functions.

- Extinguishing temperature = Set temperature + 7°C

2) Set the indoor temperature

- Temperature setting range: 5~40 degrees

- Ignition temperature = Set temperature - 1 degree

- Extinguishing temperature = Set temperature + 1°C

Domestic Hot Water Operation

1) Water flow sensor: Operates when the flow rate is approximately 2.5 L/min or higher.

2) Domestic hot water setting range: typically 35–50°C, adjustable during use.

High-temperature use: 50–60°C; adjustable after use is discontinued.

3) Ignition temperature = set temperature - 1°C, extinguishing temperature = set temperature + 7°C

4) Domestic hot water can be used for up to 90 minutes (adjustable via special functions).

3. Pressure Range

1) Operating pressure range: 0.3–3.0 bar

- When the pressure is less than 0.3 bar, it is detected as “no water,” displayed as E-07 (low water pressure), and the pump stops running.

-At this point, open the manual make-up water valve to add water (recommended pressure: 1–1.5 bar).

- When the pressure exceeds 3.0 bar, the relief valve opens to discharge water and displays E-08 (high water pressure).

4. Overheating

1) Overheat occurs when the heating water temperature or domestic hot water temperature exceeds 95°C, and an alarm is triggered. After the water temperature drops below 80°C, the overheat condition can be cleared using the front-panel thermostat.

5. Prevent the water pump from seizing up

1) To prevent the water pump from seizing, if it has not operated for 24 hours, the boiler will automatically run for 1 minute to provide heating, and the hot water circulation pump will operate for 30 seconds.

2) The water pump stops running when E-07 (low water pressure) is displayed.

6. Freeze protection function (= same as the away function)

1) When the heating water temperature drops below 12°C, run the heater for 1 minute every 2 hours, and operate the hot water pump for 30 seconds.

2) When the heating water temperature drops below 7°C, run the heater for 2 minutes every 10 minutes, and run the hot water pump for 1 minute.

3) When the heating water temperature drops below 4°C, ignite and burn; stop operation when it reaches 30°C.

4) The antifreeze function can only be activated when water, electricity, and gas are turned on.

- When the boiler is fully configured and fine-tuning is required based on site conditions, only personnel who have received specialized training may perform such adjustments.

- Special Function Setup Method

1. Front panel thermostat: Press and hold the Time button and the Hot Water button simultaneously for more than 2 seconds.

2. The LCD displays “no 01” and flashes continuously; at this point, adjust the digits using the knob.

3. Select the content, then press the knob to confirm.

4. At this point, the selected number flashes; then use the knob.

5. Select the desired item, then press the knob once to confirm, returning to the No. 01 interface.

6. Other adjustment functions are set in the same way as above; after setting, press the power button once to exit.

- Types of special functions

00 -> Initialization function u: Maintain current setting d: Initialize and return to factory settings

01 -> Thermostat Display Light Switch (Default: on)

On: Thermostat light on OFF: Thermostat light off

02 -> When operating on a timed schedule, the boiler’s 1-hour run time value (default: 30 minutes)

The boiler’s 1-hour operating time can be set to (30, 45, 60, or 15) minutes.

03 -> Three-way method after domestic hot water use: Standby time setting (Default: 12 (120 seconds)) During domestic hot water usage, temporarily interrupt and adjust the standby time (03 (30 seconds), 06 (60 seconds), 12 (120 seconds), 18 (180 seconds)). 04 -> Heating water temperature control switch: When switching to room temperature control, set the difference between the set temperature and the ignition temperature (Default: 1 degree -> Ignition temperature = Set temperature - 1 degree (1, 2, 3, 4) degrees, column). 2 degrees setting -> Ignition temperature = Set temperature - 2 degrees. Reference: Extinguishing temperature = Set temperature + 1 degree.

05 -> Flow sensor activation time setting when using domestic hot water (Default: 10 seconds)

Adjusting the water flow sensor makes hot water use more convenient. However, if it is too sensitive when dispensing hot water quickly, it can cause water to flow into other drain lines and trigger the boiler, increasing gas consumption.

( 10 (1 second), 03 ( 0.3 seconds), 30 (3 seconds) )

06 -> Adjust fan speed ( Default: 0 )

The fan speed can be adjusted, but this must not interfere with the boiler’s normal combustion.

(-3, -2, -1, 0, 1, 2, 3) positions; each step changes the speed by approximately 45 RPM.

07 -> Trial Run Function ( Basic : OFF )

Run the pump for 10 minutes without operating the boiler. During initial setup, the boiler is used for water make-up and air venting; however, in a low-water condition (displaying E-07 low water pressure fault), the pump stops immediately.

( ON (pump runs for 10 minutes), OFF (stop pump) )

08 -> BUZER uses ON/OFF setting (Default: ON)

Settings for Use/Prohibition of Built-in Accessories on the PCB Motherboard

( ON (Accessory Use), OFF (Accessory Use Prohibited)

Older model boiler fault codes

Code:

Hot water temperature sensor malfunction. 1. Inspect the hot water sensor; it may be covered in limescale and need cleaning. 2. Check the main board.

Code:

Refilling water more than five times within one minute; 1) check whether the pipes are low on water; 2) check the system for leaks; 3) another possibility is that the boiler has no pressure and needs to be refilled.

Code:

When the flame sensor detects a flame during abnormal flame-out detection, check the following: 1. Is the infrared sensor dirty? 2. The mica sheet may also be dirty and needs cleaning. 3. Inspect the main board.

Code:

Incomplete combustion. During firing, the flame produces a yellow flame. 1. Check whether the flue is obstructed or not venting properly. 2. Inspect the flame’s combustion condition. 3. Verify the gas pressure at the proportional valve. 4. Check if the blower is dirty.

Code:

Fan malfunction. During ignition, the air supply fan fails to spin at all within 3 seconds, or spins abnormally for 30 minutes. 1. Check the fan. 2. Inspect the fan for dirt and clean it if necessary. 3. Check the main board.

Code:

Heating Leak Detection: 1. Inspect system piping for leaks. 2. Inspect the boiler for leaks.

Code:

Boiler fails to ignite: 1. Check if the gas supply is normal. 2. Inspect the infrared sensor. 3. Examine the ignition transformer. 4. Verify that the gas proportional valve is open. Potential issues: 1. Insufficient gas pressure—adjust the gas pressure. 2. Check the gas nozzle for blockages. 3. Inspect the overheat protection device for damage. 4. Test the air pressure switch. 5. Inspect the main board.

Code:

Is the power supply frequency the same? Confirm the power supply frequency.

Code:

Water shortage check pressure

Code:

Poor contact in the thermostat: 1. Check the thermostat; 2. Check the main board; 3. Check the wiring.

Code:

Overheat protection: check the circulating pump; check the circulating water status. 3. Verify that air has been fully purged from the system to prevent overheat protection. 4. Inspect the heat exchanger for blockages. 5. Check the temperature probe.

Code:

The temperature sensor inside the thermostat is faulty. 1. Check the thermostat. 2. Check the thermostat’s temperature sensor.

Code:

The motherboard does not match the boiler model, the motherboard’s transfer switch is not set correctly, and the numbers on the motherboard code are incorrect.

Code:

1. No water in the heating pipes; 2. Automatic make-up water switch; 3. Water level sensor safety switch—water cut-off; 4. Expansion tank is depressurized.

Code:

Poor communication between the motherboard and the thermostat: 1. Check the thermostat, the motherboard, and the thermostat connection cable.

Code:

Hot water temperature sensor fault: 1. Check the temperature probe for scale buildup. 2. Inspect the main board.

Code:

If the water flow sensor detects water flow for more than 30 minutes: 1. Check the water flow sensor; 2. Inspect the pipes for leaks; 3. Check the main board.