VOKERA Unica 28HE - User Manual

THESE INSTRUCTIONS
TO BE RETAINED
BY USER
Vokèra is a licensed member of the Benchmark scheme
which aims to improve the standards of installation and
commissioning of domestic hot water systems in the UK.
Unica Balcony boiler
High efficiency combi boiler
Users
Instructions
G.C. NUMBER
UNICA 32 BHE N° 47-094-99
0694
0694BR1207

Summary

Things You Should Know

Gas Appliances

Ensures compliance with UK Gas Safety regulations for safe installation and upkeep.

Electrical Supply

Frost Protection System

Appliance Status Indicators

Digital Display

Getting Started

Appliance Controls

Lighting the Boiler

Adjusting the Heating Temperature

Adjusting the Hot Water Temperature

How To...

How to Top-Up the System Pressure

Detailed steps for checking and topping up system pressure using the filling valve.

How to Reset the Appliance

Instructions on how to reset the appliance when the Red LED fault indicator is on.

What If...

What if I Suspect a Gas Leak

Critical steps: turn off gas supply, contact installer or gas supplier.

What if I Have Frequently to Top-Up the System

Advise to contact installer if system pressure needs frequent topping-up, indicating a leak.

What if the Reset Light is On

Explains Red LED indicates fault, auto shutdown, and manual reset requirement.

What if the Appliance is Due its Annual Service

What if I Need to Call an Engineer

Advice on contacting Vokera Customer Services or an engineer with necessary details.

Overview

1. Function Description
2. Usage Features
3. Lighting the Boiler
4. Topping Up the System Pressure
5. Resetting the Appliance
6. Shutting Down the System
7. Setting the Mechanical Clock (if fitted)
8. Maintenance Features
9. Annual Service
10. Cleaning the Appliance
11. Appliance Log Book
12. General Do's and Don'ts

The Vokèra Unica Balcony boiler is a high-efficiency combi boiler designed for domestic heating and hot water systems. This user manual provides essential information for its safe and efficient operation, maintenance, and troubleshooting.

Function Description

The Unica BHE boiler provides heated water for both radiators (central heating) and domestic hot water (DHW) taps. It operates electronically, eliminating the need for a pilot light. The boiler is equipped with a built-in frost protection system that allows it to override time controls and operate the burner and/or pump if the temperature drops below 6°C for the main unit or 4°C for the DHW line. This system ensures the boiler's internal components are protected from freezing, with the burner remaining active until the main temperature reaches 35°C for central heating and 55°C for domestic hot water. It's important to note that this frost protection is designed solely for the appliance itself; additional controls may be necessary for comprehensive heating system frost protection. The boiler also features a safety lockout mechanism that automatically terminates the gas supply to the burner in the event of a fault.

Usage Features

Before operating the boiler, users should familiarise themselves with how to isolate the appliance from gas, water, and electricity supplies, check and top-up the system water pressure, and understand the functions of any external thermostats and the integral time clock or programmer.

The appliance controls are located on the lower front of the unit and include:

• Pressure Gauge: Displays the current pressure of the heating system, which should ideally be between 1 and 1.5 BAR when the boiler is off and cooled to room temperature. A slight fluctuation during operation is normal. If the pressure drops below 0.5 BAR, the boiler may lock out.
• Appliance Mode Selector Switch: Used to select various operating modes:
  • OFF/RESET: Turns the boiler off and resets it after a fault.
  • DHW MODE: Activates domestic hot water production.
  • CH MODE: Activates central heating.
  • CH with PREHEATING MODE: Activates central heating with a preheating function for faster hot water delivery. The frost protection system remains active in all these modes.
• Temperature Selectors: Two rotary knobs allow users to adjust the temperature of the water for central heating and domestic hot water independently.
  • Central Heating Temperature: Adjustable between 40°C and 80°C for standard CH mode. If floor heating mode is selected (via an internal jumper), the range can be modified to 20°C to 45°C.
  • Domestic Hot Water Temperature: Adjustable between 35°C and 60°C. If the outlet water is not hot enough, reducing the flow rate at the tap may be necessary.
• 2-digit LED Display: Normally shows the current working (outlet) temperature of the boiler. In specific circumstances, it will display fault codes or characters indicating a particular function (e.g., 'AF' for frost protection).
• Status Indicators:
  • Green LED: Illuminates when the flame is present and the burner is ON.
  • Red LED: Illuminates when the appliance has detected a fault and performed a safety lockout.

Lighting the Boiler:

To light the boiler, ensure the gas and electrical supplies are turned on. Rotate the mode selector switch to the ON position. The boiler will initiate an ignition sequence when there is a demand for heating or hot water from the time clock or programmer. Once the set temperature is reached, the burner will turn off for a minimum of approximately 3 minutes. The appliance will automatically switch off when the heating request is satisfied. If the appliance fails to ignite during the sequence, it will enter a lockout condition, requiring a manual reset after a two-minute waiting period.

Topping Up the System Pressure:

Periodically check the system pressure. If it needs topping up, locate the filling valve connections (usually beneath the boiler), attach the filling loop, and slowly open the filling valve until the pressure gauge reads between 1 and 1.5 BAR. Then, close the filling valve and remove the filling loop.

Resetting the Appliance:

If the red fault LED is illuminated, the appliance needs to be manually reset. Before resetting, consult the fault code table in the manual to understand the required action. After a two-minute waiting period, rotate the mode selector knob across the OFF/RESET position. Frequent resets may indicate a fault, and professional assistance should be sought.

Shutting Down the System:

• Short Periods: Turn the time clock to the off position. It is also advisable to turn off the main water supply to the house.
• Long Periods (especially during winter): The system should be thoroughly drained of all water. The gas, water, and electricity supplies to the house should also be turned off. Consult your installer for detailed advice.

Setting the Mechanical Clock (if fitted):

• Setting the Time: Grasp the outer edge of the black dial and turn it clockwise until the correct time aligns with the white pointer.
• Setting Switching Times: Slide the black tappets adjacent to the desired time periods to the outer edge of the dial for "ON" periods. Tappets remaining at the centre represent "OFF" periods. The smallest switching time is 15 minutes.
• Selector Switch: Move the selector switch to the central position for "AUTO" mode, bottom position for "ON" mode, and upper position for "OFF" mode.

Maintenance Features

Annual Service:

The appliance is due for an annual service to ensure its continued safe and efficient operation. Homeowners should contact Vokèra Customer Service or a local CORGI registered engineer. Tenants should arrange servicing through their landlord. Regular servicing is crucial for maintaining the warranty and ensuring optimal performance.

Cleaning the Appliance:

To clean the outer casing, use only a clean, damp cloth. Abrasive cleaners or scourers should not be used as they can damage the finish.

Appliance Log Book:

The appliance log book, located at the rear of the installation booklet, must be completed by the installer during installation/commissioning. This document records important details, including the CORGI registration number of the installer. Failure to install and commission the appliance according to manufacturer instructions may invalidate the warranty.

General Do's and Don'ts:

• Do: Ensure the system pressure is checked periodically.
• Do: Know how to isolate the appliance in an emergency.
• Do: Familiarise yourself with the appliance controls.
• Do: Ensure your installer has completed the appliance log book.
• Do Not: Attempt to remove the appliance casing or gain internal access.
• Do Not: Hang clothes or other items over the appliance.
• Do Not: Forget to have the appliance serviced annually.

This user manual is an integral part of the appliance and should be retained by the user. A replacement copy can be obtained from Vokèra customer services if needed.

VOKERA Unica 28HE Specifications