REMEHA Flexistor 400 User manual

7038477_issue _01
Installation Manual
Unvented Flexistor Water Heaters Installation & Servicing Instructions

Important
Please read & understand all these instructions before commencing installation.
This cylinder range does not incorporate an internal heat exchanger.
Please leave this manual with the customer for future reference.
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Contents
Product Specification
Introduction
General requirements
THE BENCHMARK™ SCHEME
Checklist
Storage and handling
Technical data
ErP data information
Immersion allocation table
Thermostat control schematics
Wiring Schematics
Limitations
Water supply
Installation & Commissioning
General Installation
Cold Water Supply
Secondary circulation and De-Stratification
Discharge Pipe work
Direct Model
Commissioning
Maintenance & Servicing
Maintenance requirements
Clean the strainer

Fault finding
Servicing
Spares
Accessories
Spares drawings
Benchmark check list
Service Record
Warranty
Lifetime Warranty Terms and Conditions
THE BENCHMARK™ SCHEME
Benchmark™ places responsibilities on both manufacturers and installers. The purpose is to ensure that customers are provided with the
correct equipment for their needs, that it is installed, commissioned and serviced in accordance with the manufacturer's instructions by
competent persons and that it meets the requirements of the appropriate Building Regulations. The Benchmark™ Checklist can be used to
demonstrate compliance with Building Regulations and should be provided to the customer for future reference. Installers are required to carry
out installation, commissioning and servicing work in accordance with the Benchmark™ Code of Practice which is available from the Heating
and Hotwater Industry Council who manage and promote the Scheme. Visit www.centralheating.co.uk for more information.
IMPORTANT NOTE TO USER: PLEASE REFER TO THE USER GUIDE SECTION ON PAGES 34 FOR IMPORTANT
INFORMATION WITH RESPECT TO THE BENCHMARK SCHEME
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Product specification
Introduction

Congratulations on your purchase of a Remeha Flexistor unvented water heater. The Remeha Flexistor products are manufactured in the UK
from top quality materials and meets all the latest relevant safety and constructional standards. The high grade Duplex stainless steel cylinder
offers exceptional strength and corrosion resistance which is backed by a 30 year warranty* Its performance and insulation levels exceed the
latest requirements of Building Regulation Part L.
The Remeha Flexistor unvented water heater can be fed directly from the cold water mains supply to the property without the need for separate
feed cisterns or vent pipes. It is supplied complete with all its necessary inlet and safety controls.
The Remeha Flexistor cylinder range all require a separate expansion vessel to accommodate any expanded water.
General Requirements
IMPORTANT: Please read and understand this product guide before installing the Remeha Flexistor water heater. Incorrect installation may
invalidate the warranty*.
The Remeha Flexistor must be Installed, Commissioned and Maintained by a competent installer in accordance with Building Regulation
G3 (England and Wales), Technical Standard P3 (Scotland) or Building Regulation P5 (Northern Ireland) and the Water Fitting Regulations
(England and Wales) or Water Byelaws (Scotland).
* See Terms and Conditions of warranty
THIS APPLIANCE CAN BE USED BY CHILDREN AGED FROM 8 YEARS AND ABOVE AND PERSONS WITH REDUCED
PHYSICAL, SENSORY OR MENTAL CAPABILITIES OR LACK OF EXPERIENCE AND KNOWLEDGE IF THEY HAVE
BEEN GIVEN SUPERVISION OR INSTRUCTION CONCERNING USE OF THE APPLIANCE IN A SAFE WAY AND
UNDERSTAND THE HAZARDS INVOLVED. CHILDREN SHALL NOT PLAY WITH THE APPLIANCE. CLEANING AND USER
MAINTENANCE SHALL NOT BE MADE BY CHILDREN WITHOUT SUPERVISION
WARNING: Do not switch on if there is a possibility that the water in the heater is frozen.
Also:
#Water may drip from the discharge pipe of the pressure-relief device and this pipe must be left open to the atmosphere; (see here for more
details)
#The pressure-relief device is to be operated regularly to remove lime deposits and to verify that it is not blocked; (see here for more
details)
#How hot water can be drained. (see here for more details)
#A discharge pipe connected to the pressure-relief device is to be installed in a continuously downward direction and in frost free
environment; (see here for details)
#Details on how to set the temperature controls for immersion heaters can be found here.
Note: This Remeha Flexistor cylinder needs a minimum 100L/min water supply at open outlet.
Important Notice:
When installed with the KIWA approved unvented kit Remeha Flexistore cylinders are approved as meeting current water regulations.

To satisfy these regulations when the kit is not supplied it will be required that the installer ensures that all of the system components
meet the required standards.
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Checklist (if purchased through Heatrae Sadia)
Before commencing installation check that all the components for your Remeha Flexistor unit are contained in the package.
The following components are supplied as standard with your Remeha Flexistor unit:
Commercial
Cylinder
Volume (ltr)
Pressure
Reducing Valve Pressure Relief Valve Single Check Valve
400 - 500 1" Integrated inlet control valve
800 1.25" (1.5 - 6 bar) 1" x 1.25" (8 bar) 1.25"
1000 1.25" (1.5 - 6 bar 1" x 1.25" (8 bar 1.25"
1250 - 1450 1.5" (1.5 - 6 bar 1" x 1.25" (8 bar 1.5"
2000 - 2500 2" (1.5 - 6 bar 1.25" x 1.5" (8 bar 2"
Table 1: Cold Water Inlet Control Kit (depending on model)
Commercial
Cylinder
Volume (ltr)
Expansion Vessel
Size (ltr) Mounting Kit Weights
400 - 500 60 Floor Mounted 12kg
800 100 Floor Mounted 17kg
1000 - 1250 150 Floor Mounted 24kg
1450 200 Floor Mounted 38.5kg
2000 - 2500 300 Floor Mounted 41kg
Table 2: Expansion Vessel Sizing
#Factory fitted Temperature & Pressure Relief Valve, set at 90°C / 1 MPa (10bar). Connection size 1 1/4" BSP male to cylinder and 1 1/4"
BSP female outlet.
#Tundish 1 1/4" inlet, 1 1/2" outlet
#Isolating Valve (2")
#1" Drain Valve.

#All connections BSP female.
Notes:
1" Integrated inlet control valve is not assembled.
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Storage and Handling
Please take care when handling a packaged Remeha Flexistor. The unit is heavy and must only be moved manually within safe working
practices. If the unit is to be stored before installation, it must be placed on a secure, level surface and in a dry, frost free environment.
Precautions to be carried out prior to commencement of work:
1. Tidy area ensuring there is safe access and egress to installation place, free from trip hazards.
2. Be aware of other people who may be in the area
3. Operate any machinery in accordance with training and operating instructions
4. Visually inspect the equipment prior to use, do not use damaged equipment.
5. Safe working practices are adopted for manual handling of appliances/parts
6. Correct PPE to be worn.
The Remeha Flexistor unit must be vertically floor mounted. It can be placed anywhere convenient provided the discharge pipe(s) from its safety
valves can be correctly installed. Areas that are subject to freezing must be avoided. Ensure that the floor is level and of sufficient strength to
support the "full" weight of the unit when filled with water (refer to Table 5 for unit weights). Pipe runs should be kept as short as possible for
maximum economy. Access to associated controls, immersion heaters and indirect controls should be possible for servicing and maintenance of
the system.
To aid installation, the Remeha Flexistor is provided with lifting points located at the top of the unit. To access the lifting eyes please remove the
red outlet grommet and the top cover. The weights of the units are noted on Table 5.

FIGURE 1: Lifting
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Technical data (Indirect models in conformance with BS EN 12897:2016)
Maximum mains water supply pressure 2.5MPa (25 bar)
Operating pressure/PRV 0.60MPa (6. bar)
Expansion vessel pressure 1.0MPa (10 bar max)
Expansion relief valve setting 0.8MPa (8 bar)
Maximum design pressure 0.80MPa (8 bar)
T&P relief valve setting 1.0MPa/90 °C (10 bar)
Immersion heater rating (a.c. supply only) single phase 6kW & 9kW 50/60Hz ~
Immersion heater rating (a.c. supply only) 3 phase
(See Accessories for full range) 12kW - 54kW 50/60Hz ~
Storage weights (empty and full) See Table 4
See Table 6
ErP data
ErP Data
Model(s) 400 500 800 1000 1250 1450 2000
Energy efficiency class B C C C C C C
Standing loss W 72.0 89.0 114.0 139.0 150.0 163.0 179.0
Storage volume V in Litres 400 500 800 1000 1250 1450 2000
Table 3: ErP Data Information
Technical parameters in accordance with European Commission regulations 814/2013 and 812/2013
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