OSO 20 RI User Manual

20 RD
20 RI
IM/5a
Installation details
The OSO unvented unit is designed for use with supply pressure up to 16 bar. For pressures over
16 bar an additional pressure reducing valve must be fitted in the supply pipe to the unit.
Wall mounting brackets are available for OSO unvented units 100-170 litres capacity.
Components supplied with the unit for site fitting
(See also page 2 for component list)
*
Multibloc valve, includes pressure reducing valve, line strainer, balanced cold water take off,
(for shower or bidet only) check and expansion valve.
*
Tundish
*
1/2''F x 15 x 15 tee piece.
*
Flexible hose.
*
3/4'' x 22mm Elbow / Drain Cock.
*
Commissioning valve, 1/2'' BSP male.
*
Motorised valve (indirect only).
Components factory fitted
*
Immersion heater(s).
*
Thermostats / thermal cut-out.
*
Temperature and pressure relief valve.
This manual gives detailed advice for installation and should be read carefully
prior to fitting any unvented unit. Where components are supplied only for
indirect units, this is clearly shown.
This OSO cylinder must be installed by a competent person and be installed in
compliance with the OSO Installation and Maintenance Instructions, all current
legislation, codes of practice and regulations governing the installation of
unvented hot water cylinders in force at the date of installation.
-1-
PLEASE LEAVE THIS MANUAL WITH THE OSO UNIT AFTER INSTALLATION
INSTALLATION MANUAL
PRODUCT REF.
HEIGHT
DIAMETER
WEIGHT EMPTY
MAX WEIGHT FULL
100
720
580
34
132
900
580
40
163
1150
580
48
215
125 170
1400
580
60
261
210
1600
580
64
303
250
2090
580
82
397
330
DIMENSION AND WEIGHTS TABLE 1
00142040-06 IM/5
Health and Safety
Manual Handling Operations Regulations 1992 defines manual
handling as: “any transporting or supporting of a load (including the
lifting, putting down, pushing, pulling, carrying or moving thereof) by
hand or bodily force”. The Regulations set no specific requirements
such as weight limits. However common sense still has to be used
based on an ergonomic approach for each individual.
20S (IM) 16pp ISSUE 8

OSO 20 RI Specifications

General

Brand	OSO
Model	20 RI
Category	Water Heater
Language	English

Summary

Installation Manual Overview

Components Supplied for Site Fitting

Lists components provided with the unit for installation on-site, such as valves, tundish, and fittings.

Components Factory Fitted

Details components that are pre-installed on the OSO cylinder, including immersion heaters and thermostats.

Installation Details

Provides key information regarding the installation of the OSO unvented unit, including pressure limits.

Health and Safety

Highlights Manual Handling Operations Regulations and general safety considerations for installation.

Cold Water Supply

Cold Water Supply Installation Steps

Detailed instructions for connecting the cold water supply to the unit, including valve and pipe fittings.

Hot Water Supply Connection

Guidance on connecting the hot water supply pipe to the unit's outlet.

Secondary Return Installation

Instructions for fitting the secondary return facility using a tee piece.

Discharge Pipe Connection

Requirements for connecting the discharge pipe from the tundish, ensuring a continuous fall.

Primary Flow & Return (Indirect Only)

Details on connecting the boiler primary flow and return, including by-pass and motorised valve.

Commissioning Procedures

Filling Up the System

Step-by-step guide for filling the unvented system with water and checking for leaks.

Draining the Unit

Instructions on how to safely drain the OSO unit for maintenance or servicing.

Safety and Maintenance

Safety Cut-out Operation

Explains the conditions under which the safety cut-out operates and how to reset it.

Cold or Tepid Water Discharge

Procedure for addressing cold or tepid water discharge from the tundish.

Installation and Servicing Instructions

Cold Water Inlet Control (Multibloc)

Details on the pressure reducing valve, strainer, and expansion valve combination unit.

General Installation Guidelines

Provides specific advice for installing the Multibloc unit and managing expansion relief pipework.

Maintenance Procedures

Pressure Reducing Valve Maintenance

Instructions for cleaning and maintaining the pressure reducing valve and its strainer.

Expansion Relief Cartridge Maintenance

Guide for servicing the expansion relief cartridge, including cleaning the valve seat.

Spare Parts Identification

Lists part numbers for spare components like pressure reducing valve cartridges and expansion valves.

Tundish Installation Requirements

Specifies the correct installation position and pipework for the tundish.

Electrical Installation

Immersion Heater Installation

Wiring instructions and safety precautions for immersion heaters in direct and indirect units.

Direct Units Wiring

Details on connecting immersion heaters for direct units, including safety cut-out.

Indirect Units - Motorised Valve

Installation and wiring of the motorised valve for indirect units to control primary flow.

S Plan Wiring Layout

S Plan System Schematic

Y Plan Wiring Layout

Y Plan System Schematic

OSO Fault Finding Guide

No Water Flow from Hot Taps

Troubleshooting steps for lack of hot water flow, including checks for supply and strainers.

Water from Hot Taps is Cold

Diagnosing why hot water is cold, checking immersion heaters, thermostats, and programmer settings.

Intermittent Water Discharge

Causes and remedies for intermittent water discharge, relating to expansion or thermal control.

Continuous Water Discharge

Troubleshooting continuous water discharge from relief valves or pressure reducing valves.

Increased Volumes and High Pressure Operation

Alternative Discharge Arrangements

Secondary Return System