LST DIRECT STORAGE VESSEL

1.0 INTRODUCTION

The Lochinvar LST is a direct storage vessel, featuring a vitreous enamel lined steel storage vessel, a relief valve tapping, and a unique distribution baffle fitted to the inlet connection that maximises peak demand water delivery. It also incorporates a 100mm clean out access opening for inspection of the internal surface.

Sacrificial magnesium anodes are fitted for corrosion protection. A pocket for a temperature control device (aqua stat) and a drain valve are also fitted.

Two bosses are provided for immersion heater installation.

All installations must conform to relevant Building Regulations. Health & Safety requirements must be considered during installation. Failure to comply may lead to prosecution.

When connecting to an unvented (pressurised) system, ensure all extra safety requirements are satisfied for high or low-pressure conditions.

1.1 ANCILLARY OPTIONS

• Correx Non-Sacrificial Electrical Anode (CKT9001)
• 6kW 415v Immersion heater 15" (CSI107)
• 6kW 415v Immersion heater 16" (CSI111)
• 9kW 451v Immersion heater 21" (CSI112)
• 12kW 415v Immersion heater 24" (CSI115)
• 18kW 415v Immersion heater 27" (CSI416)
• De-Stratification Kit (WH9)

2.0 SAFETY GUIDELINES

Read all instructions carefully before commencing installation. Keep these instructions near the water heater for quick reference.

This equipment must be installed by a competent person, conforming to relevant Building Regulations and Health & Safety requirements. Failure to comply may lead to prosecution.

Commissioning, maintenance, and repair must be performed by a skilled installer/engineer according to applicable standards and regulations.

2.1 GENERAL DESCRIPTION OF SAFETY SYMBOLS USED

Lochinvar Limited is not liable for damage caused by inaccurately following these instructions. Only original parts may be used for repair or service.

This appliance is not intended for use by persons (including children) with reduced physical, sensory, or mental capabilities, or lack of experience and knowledge, unless supervised or instructed by a person responsible for their safety. Children should be supervised to ensure they do not play with the appliance.

2.2 DIMENSIONAL DRAWINGS

The vessel is a cylinder with the following features:

• Top: 2" NPT OUTLET
• Top Connection: 1" T&P CONNECTION
• Side Connections: IMMERSION HEATER CONNECTION (two ports), ANODE (two ports)
• Lower Connections: AQUASTAT, 2-1/2" NPT, HANDHOLE, 3/4" NPT DRAIN CONNECTION
• Dimensions: Diameter 863mm, Height 1955mm. The handhole is located 178mm from the bottom, with another connection at 279mm from the bottom.

3.0 TECHNICAL DATA

3.1.1 TECHNICAL SPECIFICATIONS

(Details not provided in the excerpt)

4.0 GENERAL REQUIREMENTS

The Lochinvar LST direct storage vessel is designed for many years of trouble-free operation. Follow these instructions closely for maximum usage and efficiency. Read the instructions fully before installing or using the appliance.

4.1 RELATED DOCUMENTS

Installation should follow guidance from the following documents:

• BS 6700: 1997: Design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages.
• BS 7074: 1989 Parts 1and 2: Application, selection and installation of expansion vessels and ancillary equipment for sealed systems.
• BS 7671: 2008: Requirements for electrical installations, I.E.E. wiring regulations seventeenth edition.
• CP 342: Part 2 1974: Code of practice for centralised hot water supply – buildings other than dwellings.

5.0 WATER QUALITY

Water supply quality can affect the efficiency and performance of water heaters. This is more critical at higher temperatures or demands.

Water hardness should not exceed 205ppm CaCO3, and TDS (Total Dissolved Solids) of untreated water should not exceed 350ppm. Contact Lochinvar Limited for guidance if these values are exceeded.

Water hardness requirements stated in the primary heat source's Installation, Commissioning, and Maintenance Instructions must be followed if the unit is not used as an electric storage vessel only; these requirements override this manual.

5.1 ELECTRICAL ANODE PROTECTION EQUIPMENT

The optional Correx electrical anode protection system protects the storage vessel from electrolytic attack by passing a small current from an electrode to the internal surface. It does not inhibit scale.

When the system is working correctly, a green light is visible on the Correx unit. A flashing red light indicates an error, requiring urgent remedial action.

Requirement: The unit must be connected to a PERMANENT UNINTERRUPTIBLE 230V POWER SUPPLY. No switches, including time clocks, are permitted in the electrical system other than the main isolator. Incorrect installation invalidates the warranty.

6.0 WATER CONNECTIONS

6.1 GENERAL

1. Circulating pipework, cisterns, expansion vessels, and pipework in freezing conditions must be insulated.
2. Drain valves must be accessible for draining the entire system.
3. Ideally, fit individual valves to each unit for system isolation.

6.2 OPEN VENTED SYSTEM

The Lochinvar LST can be used in an open vented system if a vent pipe compliant with CP342 or BS6700 is fitted. The minimum static head requirement will be detailed in the primary heat source's ICM Instructions. Contact Lochinvar Limited for pipework schematics for multiple appliances.

Abbreviations Used in Pipework Diagrams:

• IV = ISOLATION VALVE
• NRV = NON-RETURN VALVE
• TD = TUNDISH
• LSV = LOCKSHIELD VALVE
• TPRV = TEMPERATURE & PRESSURE RELIEF VALVE
• DV = DRAIN VALVE
• BRP = BUILDING RETURN PUMP
• PCP = PRIMARY CIRCULATING PUMP
• EV = EXPANSION VESSEL
• CP = CIRCULATING PUMP
• TPV = THREE PORT VALVE
• * = OPTIONAL

6.2.1 RECOMMENDED PIPEWORK FOR A CONDENSING CIRCULATING APPLIANCE

This diagram illustrates the recommended pipework configuration for connecting the LST vessel to a condensing circulating water heater in an open-vented system, showing the flow and return paths, cold water supply, vent pipe, and associated valves and components.

6.2.2 RECOMMENDED PIPEWORK FOR A NON-CONDENSING CIRCULATING APPLIANCE

This diagram shows the recommended pipework for a non-condensing circulating appliance in an open-vented system, detailing the connections from the cold water storage tank, through the LST vessel, to the water heater, including necessary valves and pumps.

6.2.3 RECOMMENDED PIPEWORK FOR A STORAGE APPLIANCE

This diagram illustrates the pipework for an open-vented storage appliance setup, showing the LST vessel connected to a storage water heater, with cold water supply, building return, and associated valves.

6.3 UN-VENTED SYSTEM

It is legally required for all unvented hot water systems to be installed by an approved installer.

For unvented arrangements, the system must follow BS6700 guidance and comply with The Building Regulations: Part G3 (England/Wales), P5 (Northern Ireland), and P3 (Scotland). Lochinvar Limited offers suitably sized component kits for unvented or boosted operation.

6.3.1 RECOMMENDED PIPEWORK FOR A NON-CONDENSING CIRCULATING APPLIANCE

This diagram depicts the pipework for an unvented system with a non-condensing circulating water heater, showing the cold feed, storage vessel, expansion vessel, pressure reducing valve, and other components.

6.3.1 RECOMMENDED PIPEWORK FOR A CONDENSING CIRCULATING APPLIANCE

This diagram illustrates the pipework for an unvented system with a condensing circulating water heater, showing the boosted cold feed, storage vessel, expansion vessel, and associated valves and pumps.

6.3.2 RECOMMENDED PIPEWORK FOR A STORAGE APPLIANCE

This diagram shows the pipework for an unvented storage appliance setup, including the LST vessel, storage water heater, expansion vessel, and various valves.

6.3.3 TEMPERATURE AND PRESSURE RELIEF VALVE

The unvented water system kit includes a temperature and pressure relief valve with a lift pressure of 7 bar and a lift temperature of 90°C. This valve must be fitted to the relief valve tapping.

ℹ️ The storage vessel relief valve connection must not be used for any other purpose.

6.3.4 RELIEF VALVE DISCHARGE PIPEWORK

Discharge water must run freely to a tundish. The tundish should be mounted vertically, visibly, close to the safety device (within 600mm), and in the same space as the storage system.

The discharge pipe from the tundish must terminate safely, be capable of withstanding high temperatures, and be clearly marked.

Pipe sizing criteria:

• At least one pipe size larger than the safety device outlet, unless total equivalent hydraulic resistance exceeds that of a 9m straight pipe. For 9-18m resistance, use two sizes larger; for 18-27m, use three sizes larger. Bends must be considered for flow resistance. An alternative is to follow BS6700 specifications.
• A vertical pipe section of at least 300mm below the tundish before any elbows or bends.
• Installed with a continuous fall of at least 1 in 200.
• Discharges must be visible at the tundish and/or final point.

Examples of acceptable discharge arrangements:

• Below a fixed grating and above a water seal in a trapped gulley.
• At a low level (up to 100mm above external surfaces), with a wire cage guard if children may come into contact.
• At a high level into a metal hopper and down pipe, with the end visible, or onto a roof (3m from plastic guttering).
• For single pipes serving multiple discharges (max 6 systems), the pipe must be at least one size larger than the largest individual discharge pipe. Consider an electronically operated warning device for dwellings with blind, infirm, or disabled occupants where discharges may not be apparent.

6.3.5 RELIEF VALVE DISCHARGE PIPEWORK (Diagram Description)

This diagram illustrates the discharge path from a safety device (e.g., Temperature Relief Valve) to a tundish, and then via a discharge pipe with a continuous fall to a trapped gully, ideally below a fixed grating.

6.3.6 EXPANSION VESSEL SIZING

The following information is based on an inlet pressure of 3.5 bar. Consult BS6700 for different inlet pressures.

Formula: VV = SV * e / 0.45, where VV = Vessel Volume, SV = System Volume, e = Coefficient of Expansion.

6.4 DE-STRATIFICATION

6.4.1 GENERAL

The De-stratification Pump Kit circulates water from the top to the bottom of the vessel, maintaining a consistent temperature and virtually eliminating bacterial contamination risk (e.g., Legionella) by achieving a uniform stored water temperature of at least 60°C.

A De-stratification pump may not be needed if the LST is installed with a circulating water heater creating high turbulent flow, or if a building loop provides sufficient mixing.

6.4.2 REQUIREMENTS

The kit meets HSE Approved Code of Practice L8 and Department of Health Memorandum HTM 04-01 recommendations for Legionella control. For full compliance, use a timer to operate the pump for at least 1 hour daily.

7.0 COMMISSIONING AND TESTING

7.1 ELECTRICAL INSTALLATION

Install and commission any ancillary items requiring an electrical supply as per their instructions.

7.2 WATER CONNECTION

Flush the system thoroughly with cold water, ensuring all valves are open and no circulating pumps are fitted. Check for leaks and repair as necessary. If configured for an unvented arrangement, check the expansion vessel cushion pressure.

7.3 PRIMARY HEAT SOURCE

Install and commission the primary heat source in conjunction with the storage vessel according to the relevant ICM Instructions.

8.0 MAINTENANCE

8.1 GENERAL

Regular servicing by a Lochinvar appointed person is recommended for trouble-free operation. All controls and safety features must be checked annually, even if the maintenance schedule is less frequent.

8.2 MAINTENANCE SCHEDULE

Service the LST every 12 months (maximum interval recommended by Lochinvar Limited). In hard water areas, more frequent servicing may be necessary.

8.3 DRAINING THE WATER SYSTEM

To drain the water heater for maintenance or to prevent freezing:

1. Turn off the water heater if applicable.
2. Connect a hose to the system drain valve.
3. Ensure the hose discharge is in an area where hot water will not cause damage or injury.
4. Close the cold-water inlet valve.
5. Open a nearby hot water outlet to vent the system.
6. Open the drain valve.
7. If draining for extended shutdown, leave the drain valve open.

8.4 INSPECTION AND CLEANING

1. Drain the storage vessel.
2. Remove the cover and gasket from the cleanout opening.
3. Remove scale or sediment carefully to avoid damaging the vitreous enamel lining.
4. Inspect the cleanout plate gasket and replace if necessary.
5. Install the gasket and cleanout plate, drawing the plate up square by tightening screws evenly.

8.5 SACRIFICIAL ANODES: INSPECTION AND REPLACEMENT

Sacrificial magnesium anodes must be inspected at least annually, unless the Correx non-sacrificial anode protection system is used.

Anodes protect against corrosion; their depletion rate depends on water quality. Inspection procedure:

1. Drain the storage vessel.
2. Remove the outer caps covering the anodes.
3. Remove each anode and inspect its condition.

Replace anodes if they have reduced in size by more than 40%, are severely pitted, or show excessive localized depletion. Clean anodes covered with particles.

When refitting, apply a suitable jointing compound to the anode threads to prevent water leakage.

Water softeners may increase anode depletion; check anodes more frequently.

8.6 CORREX ELECTRICAL ANODE PROTECTION SYSTEM

The Correx system monitors electrical current flow. A green light indicates normal operation; a flashing red light indicates a fault requiring urgent action.

Factors causing incorrect current flow include short-circuiting cables, poor conductivity between electrodes/tabs/PCB, poor conductivity between tank/earth tab/cable, and deposits on electrodes.

Troubleshooting Flowchart Summary:

The system guides troubleshooting based on the Correx unit's LED status:

• Check LED Status: Is it illuminated? If yes, is it green, or something other than solid green/flashing red? If no, check power supply.
• Power Check: Is Correx connected to a 230V supply and switched on? If not, connect correctly using a fused, unswitched isolator.
• Reset/Check Connections: Try turning power off/on. If still faulty, turn power off, check and clean wiring connections (potentiostat, electrodes, earth), ensure insulation is intact, and repair if necessary.
• Water Test: Disconnect electrodes/earth, place connections in water, turn power on. Check LED status. If still faulty, check continuity and insulation of wires.
• Component Replacement: If issues persist after checks, consider replacing the Correx unit, potentiostat, or electrodes.
• Magnesium Anode Check: If the unit still has magnesium anodes, try removing them and re-checking. If problems continue, a service call is required.

8.7 RE-FILLING THE SYSTEM

1. Close the drain valve.
2. Open a hot water fixture to allow air to escape.
3. Open the cold water supply to the water heater and allow the vessel to fill.
4. Check for water leakage.

8.8 OTHER CHECKS

8.8.1 RELIEF VALVE

Check the temperature and pressure relief valve and safety valve annually for proper operation. Lift the lever or turn the screw cap several times; the valve should operate freely and seat properly.

If no water flows, remove and inspect for obstructions or corrosion. Replace with a new valve of the recommended size if necessary.

9.0 USER INSTRUCTIONS

The LST Direct storage vessel is designed for many years of trouble-free service. It may be fitted with an electric immersion heater for backup, heating water to 60°C. Note that hot water supply will be limited when using immersion heaters.

The flow temperature can be set on the immersion heater (ideally 60°C maximum). Higher temperatures may trip the high limit thermostat and increase energy loss.

A short surge of water when a hot tap is turned on is normal for unvented systems and does not indicate a fault.

Milky water on first fill is due to tiny air bubbles and will clear quickly.

⚠️ Warning: If cold/warm water exits from the temperature and pressure relief valve (TPRV) or pressure relief valve (PRV), call your installer. If very hot water exits from either valve, switch off the heat source immediately and isolate the electricity supply to the cylinder and heat source.

The solar system is configured to heat water to its maximum economic temperature, which may vary with ambient conditions. The immersion may be programmed for specific times.

If hot water runs cool, manually switch on the immersion heater; refer to alternative energy device instructions.

10.0 ERP DATA TABLE