This document is the operating manual for the Vaillant ecoTEC plus 937, a compact gas wall-mounted boiler designed for central heating and hot water provision. It utilizes condensing technology and features a 15-liter laminar stainless steel storage tank. The boiler automatically controls heating and hot water demand in the most economical way, activating hot water provision as soon as a tap is opened.
Function Description
The ecoTEC plus 937 serves as a heat generator for sealed hot-water central heating installations and for central hot water preparation. It is a state-of-the-art appliance built to recognized safety regulations. The boiler's core function is to heat water for both domestic use and the central heating system. It incorporates a digital information and analysis system that provides real-time operating status and helps with troubleshooting.
The display shows the current heating flow temperature, the heating system filling pressure, or a status/error code. Symbols on the display indicate various operating states such as hot water preparation active, warmstart function active, heating pump in operation, actuating internal gas valve, and burner operation (with or without a flame cross indicating a fault). The system also signals flue problems.
The boiler is equipped with a frost protection function that activates if the heating water temperature falls below 5 °C, heating the circuit to approximately 30 °C. This function, along with other monitoring devices, is active only when the main switch is in the "ON" position and the boiler is connected to the mains power supply.
Usage Features
The ecoTEC plus 937 offers several user-friendly features for controlling heating and hot water:
- Operating Elements: The front panel includes a display, "i" button for information, a controller (accessory), a pressure gauge, an on/off switch, "+" and "-" buttons for navigating display screens, a "Fault Reset" button, and two rotary knobs.
- Rotary Knobs: One knob sets the heating flow temperature, while the other sets the domestic hot water temperature, switches the warmstart function on/off, and activates/deactivates the hot water storage function.
- Hot Water Temperature Setting: Users can adjust the hot water temperature between approximately 35 °C and 65 °C using the dedicated rotary knob. The set value is shown on the display during adjustment. For areas with hard water, it is recommended not to turn the knob beyond the mid-position (12 o'clock) to prevent excessive scale buildup.
- Warmstart Function: This feature provides immediate hot water at the required temperature without waiting for it to heat up. It keeps the hot water heat exchanger at a pre-selected temperature level. The warmstart function is activated by turning the hot water temperature knob clockwise to the end stop (setting 'a') and deactivated by turning it anti-clockwise to the end stop (setting 'c'). The "C" symbol on the display indicates its activation.
- Storage Tank Charging Mode: This mode for the layer charging storage tank can be activated and deactivated via the operating elements. It is only active if the warmstart function is switched on. When active, the hot water temperature knob can set temperatures to 50 °C (setting 'b') or 65 °C (setting 'a'). If deactivated, temperatures can be set to 35 °C (setting 'c') or 65 °C (setting 'a').
- Drawing Off Hot Water: When a hot water tap is opened, the unit automatically starts providing hot water. It switches off when the tap is closed, or continues to operate for the heating system or to recharge the storage tank if required.
- Heating Flow Temperature Setting: The heating flow temperature can be set using its dedicated rotary knob, typically up to 75 °C. Higher temperatures (up to 85 °C) can be set by a qualified installer through boiler parameter d.71. Recommended settings vary for spring/autumn, reasonably cold weather, and very cold weather.
- Summer Mode: The heating can be switched off in summer without affecting the hot water supply by turning the heating flow temperature knob all the way to the left.
- Room Thermostat/Weather Compensator: The boiler can be connected to a room thermostat or weather compensator for automatic operation based on set parameters. Vaillant supplies various thermostats and time controllers for economic room temperature regulation.
- Troubleshooting: The digital display shows fault codes (e.g., F.22 for low water pressure, F.28/F.29 for ignition faults, F.32 for flue gas routing faults) to assist in diagnosing problems. For ignition faults, the fault can be manually reset by pressing the "Fault Reset" button for one second.
Maintenance Features
Proper maintenance is crucial for the ecoTEC plus 937's operational readiness, reliability, and long service life:
- Regular Inspections: The manufacturer recommends regular inspections and maintenance work by a heating engineer or Vaillant Service Solutions.
- Cleaning: The exterior of the appliance should be cleaned with a damp cloth and a little soap. Abrasive scouring or cleaning agents that could damage the housing or plastic fittings should not be used.
- System Pressure Check: The filling pressure of the heating system should be regularly checked using the pressure gauge. The indicator should be in the dark grey zone (1.0 to 2.0 bar) when the system is cold. If the pressure falls below 0.8 bar, the system needs to be refilled. The appliance has a pressure sensor that signals low pressure (below 0.6 bar) by flashing the water pressure value on the display. If the pressure falls below 0.3 bar, the unit switches off, displaying error F.22.
- Leak Detection: In case of water leaks from pipes, the cold water shut-off valve should be immediately turned off, and an engineer should repair the leak.
- Legionella Protection: The units are equipped with an automatic Legionella protection system that heats the hot water tank to 70 °C once every 24 hours if the temperature falls below 50 °C. This system can be deactivated in the diagnosis level by a qualified installer.
- De-commissioning: For longer periods of de-commissioning (e.g., holidays), the gas supply stop-cock and cold water stop-cock should be turned off, and the power supply switched off. For units with a hot water storage tank, it should only be switched off if hot water is not required.
- Safety Seals: Seals on components should not be damaged or removed. Only suitably qualified heating engineers or Vaillant customer service personnel are authorized to remove sealed components.
- Professional Servicing: All installation, adjustment, service, maintenance, and repair work must be carried out by a competent person in accordance with relevant regulations (e.g., Gas Safety (Installation and Use) Regulations 1998 in the U.K.). The Benchmark gas boiler commissioning checklist in the installation manual must be completed by the installer and/or commissioning engineer.
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