MDC0031-02 iHP X Installation and Servicing

Installation and servicing instructions for stainless steel integrated heat pump (iHP) cylinders.

• MDC0031-02 iHP X Installation and Servicing manual (PDF)

Contents

Cylinder details

Your cylinder MX number can be found on the label placed on the front of the cylinder. 

Technical data

About your cylinder

The Mixergy Integrated Heat Pump Cylinder is a hot water storage cylinder which uses thermal stratification on charge (top-up) and discharge (from top-up and full circulation).

This stratification technology allows the Mixergy cylinder to partially heat (or ‘charge’) the water, reducing heat losses, improving available renewable capacity and allowing the exploitation of smart tariffs.

Mixergy’s unique approach to the iHP cylinder allows full circulation of the tank to achieve the greatest COP (Coefficient of Performance) or top-up for faster reheat times whilst still retaining better performance than a standard electric heater. The modular design brings ease of installation and servicing, with the head unit being completely removable from the cylinder via hydraulic connections.

For more information on how your cylinder works and how to get the most out of your system, please refer to the Mixergy iHP User Guide.

Heating modes

Top-up

The top-up heating mode is designed to provide hot water quickly.

Water is heated from the top of the cylinder and pushed downwards, creating a layer between hot (55°C) and cold (~15°C) (as shown above). This provides the user with hot water as quickly as 30 minutes, while also allowing for on-demand heating if more hot water is required in the short term. There is a performance impact when heating via top-up, however, the Mixergy iHP can also operate in full circulation. The performance (CoP) drop from top-up compared to full circulation is approximately 20-30%.

Full Circulation

The full circulation mode is designed for maximum efficiency.

If the highest cost savings are desired, if you are operating via schedule or hot water is required in the long term, full circulation mode can be used. This will improve the efficiency of the product. Instead of passing cold water through the head unit and returning hot water to the top of the cylinder, in full circulation mode the water is passed through the head unit at a high flow rate. It is then returned to the bottom of the cylinder. This stirs the whole tank and gradually brings the temperature from cold to hot.

Additional components

• Monobloc kit incl. pressure reducing valve, check valve, pressure and temperature relief valve and expansion relief valve
• Gauge
• Tundish
• Expansion vessel incl. mounting bracket and 3/4” x 22mm adapters
• 2 kW back-up immersion heater(s) 1.3/4” BSP (fitted)
• Powerline to Ethernet adapter TL-PA4010
• Ethernet cable
• Mixergy iHP User Guide

Design notes

The Mixergy iHP cylinder can be fitted with the following optional accessories:

• The Mixergy current clamp for binary head unit control (<250w) - from your excess solar PV, the Mixergy iHP can produce up to 3x the heat energy of a standard electric heater, making the most of your excess energy. The iHP will switch on when a minimum of 250w excess solar PV is being produced.

The unit should be handled with care in order to avoid damage. It should be stored upright in a dry place.

Schematic

Hydraulic schematic

Direct unvented

Installation: general guidelines

The installation area should be able to support the weight of the iHP (approximately 320kg for a full 250L cylinder), incoming pipes, and discharge pipe when full.

Positioning of the cylinder

The position of the cylinder should suit the installation; all connections should be to the front for ease of access.

Ensure suitable space is left for access for repair and/or replacement of immersions and valves etc. Ensure at least 350mm of vertical clearance above the cylinder from the top of the ducting spigots.

Unvented installations

Installers should ensure incoming mains pressure is less than 1 MPa (10 bar) and at-least 0.1 MPa (1 bar) with a minimum flow rate of 10 L/min. Local authority approval for installation of unvented systems must be granted.

Use of flux and sterilisation

Excessive use of flux can damage the unit, especially the valves and expansion vessel (if supplied). Avoid overuse and ensure the system is fully flushed of debris or flux after connection.

If full sterilisation of all the pipework, including the cylinder, is required, a complete drain down and flush of the unit is essential. A simple flush through with water is not adequate to remove all the sterilising solution within the cylinder.

Under no circumstances should sterilising solution be left in the cylinder any longer than required (seek dosage requirements from the chemical manufacturer).

Pipework and cold water control group

To ensure adequate flow rate, the unit should be piped in with a nominal 22mm pipe.

The unit is supplied with a monobloc pressure-reducing valve that has a set pressure of 0.3 MPa (3 bar). The valve also consists of a serviceable strainer, non-return valve, expansion relief valve, connection for an expansion vessel and balanced cold feed supply.

We strongly recommend fitting an isolating valve (not supplied) prior to the monobloc valve for ease of maintenance at a later date.

Under no circumstances should an isolating valve be fitted between the expansion vessel and the storage cylinder.

Fitting a drain valve

Please ensure that a drain valve is fitted to the lowest part of the unit. The drain valve must be fitted as low as possible so that at least 80% of the cylinder’s total capacity can be drained off.

Positioning the tundish

The tundish, which shows visible discharge from the relief valves, is to be in a prominent, visible and safe position away from any electrical devices. See discharge and safety devices section.

Checking the pump and T&P relief valve

The temperature and pressure relief valve is set at 7 bar and 90°C. Both the pump and T&P valve are factory-fitted and sealed prior to dispatch. While we endeavour to ensure there are no leaks from these seals, we would advise checking the connection as the valve/pump may have been disrupted in transit.

Fitting the expansion vessel

The expansion vessel should be checked and, if required, charged at 3.0 bar.

The vessel should be mounted securely to the wall or sufficient support with the fixing kit supplied.

The connection should be made between the vessel and monobloc kit using the included 3/4” x 22mm compression adapter.

Installation: Heat Pump Head Unit

Assembling the head unit onto the cylinder

The head unit is delivered separately to the cylinder to aid ease of installation. Once the cylinder is in the desired location, the bare head unit can then be lifted onto the top of the cylinder. Ensure to fix the head unit to the cylinder using the four M6x30 bolts provided.

Making the electrical connections

There are a total of four electrical connections to make to the head unit. All are connectorised to aid ease of assembly.

The head unit and immersion feeds use PowerCON connections. They are opposite genders to avoid incorrect assembly. To attach the mains connections, orient the largest notch on the female end with the largest socket on the male end. As per the figure below, this will result in the connector latches sitting at around 45°. They cannot be assembled in the incorrect orientation. Push connectors into the sockets, and twist clockwise to lock into place.

Making the data connections

There is a Sensor and Data cable to connect to the head unit from the controller. The Sensor cable uses a simple two-pin connector. The female end of the connector (the socket) protrudes from the connector panel and is labelled accordingly. Take the two-pin male end (the plug) from the controller and slide it onto the socket protruding from the connector panel. This sensor connection can only be inserted in one orientation and has a latch to prevent accidental removal.

The Data connection is made via Ethernet cable just above the Sensor connector panel. This Ethernet cable is already installed on the controller and is labelled accordingly. Simply plug the Ethernet cable into the RJ45 socket labelled Data on the connector panel. Ethernet cables are designed such that they can only be installed in one orientation, and have a latch to prevent accidental removal.

Assembling the pipework

• Plug the powerline adapter into a wall socket within 2m of the internet router. Do not use an extension lead as this can cause connectivity issues.
• Plug the powerline adapter into the internet router using the included 2m Ethernet cable.

Wiring an Ethernet connection

If a hard-wired CAT5/CAT5e/CAT6 network connection is desired, this can be achieved as follows:

 

1. Unscrew and remove the cylinder controller’s cover and then disconnect the blue Ethernet cable as shown.

2. Replace the removed Ethernet cable with a suitable direct connection to the network (broadband router/switch).

Installation: insulation

Pre-plumb pipework

The external pre-plumb pipework, highlighted in red below, should be insulated using class O insulation (not included). The quality of the insulation installation will affect the performance of the Mixergy iHP. Effort should be made to ensure there are no exposed sections of pipework, valves etc. This will minimise heat losses during operation.

The recommended thickness for class O insulation is 25mm for the best performance from your Mixergy iHP. 

Discharge pipework

Discharge pipes from safety devices

• Safety devices such as temperature relief valves or combined temperature and pressure relief valves should discharge either directly or by way of a manifold via a short length of metal pipe (D1) to a tundish.
• The diameter of discharge pipe (D1) should be not less than thenominal outlet size of the safety device, e.g. temperature relief valve.
• Where a manifold is used it should be sized to accept and discharge the total discharge from the discharge pipes connected to it.
• Where valves other than a temperature and pressure relief valve from a single unvented hot water system discharge by way of the same manifold that is used by the safety devices, the manifold should be factory-fitted as part of the hot water storage system unit or package.

Tundish

• The tundish should be vertical, located in the same space as the unvented hot water storage system and be fitted as close as possible to, and lower than, the safety device, with no more than 600mm of pipe between the valve outlet and the tundish. Note: to comply with the Water Supply (Water Fittings) Regulations, the tundish should incorporate a suitable air gap.
• Any discharge should be visible at the tundish. In addition, where discharges from safety devices may not be apparent,e.g. in dwellings occupied by people with impaired vision or mobility, consideration should be given to the installation of a suitable safety device to warn when discharge takes place, e.g. electronically operated.

Condensate drain hose

• The condensate drain is located to the right of the controller on the side of the cylinder. The hose, at any point in the routing, should not be installed horizontally or create a U-bend. Allowing this will cause the water discharging through the pipe to back up and overflow from the head unit.

Min size of
discharge pipe D1

Discharge pipe D2

• The discharge pipe (D2) from the tundish should have a vertical section of pipe at least 300mm long below the tundish before any elbows or bends in the pipework. It should be installed with a continuous fall of at least 1 in 200.
• The discharge pipe (D2) should be made of metal or other material that has been demonstrated to be capable of safely withstanding temperatures of the water discharged and is clearly and permanently marked to identify the product and performance standard (e.g. as specified in the relevant part of BS 7291-1:2006).
• The discharge pipe (D2) should be at least one pipe size larger than the nominal outlet size of the safety device unless its total equivalent hydraulic resistance exceeds that of a straight pipe 9m long, e. for discharge pipes between 9m and 18m the equivalent resistance length should be at least two sizes larger than the nominal outlet size of the safety device; between 18 and 27m at least 3 sizes larger, and so on; bends must be taken into account in calculating the flow resistance.
• Where a single common discharge pipe serves more than one system, it should be at least one pipe size larger than the largest individual discharge pipe (D2) to be connected.

• The discharge pipe should not be connected to a soil discharge stack unless it can be demonstrated that the soil discharge stack is capable of safely withstanding the temperatures of the water discharged, in which case, it should contain a mechanical seal, not incorporating a water trap, which allows water into the branch pipe without allowing foul air from the drain to be ventilated through the tundish.
• If plastic pipes are used as branch pipes carrying discharge from a safety device, they should be either polybutylene (PB) or cross- linked polyethylene (PE-X) complying with national standards such as Class S of BS 7291-2:2006 or Class S of BS 7291-3:2000 respectively; and be continuously marked with a warning that no sanitary appliances should be connected to the pipe.
• Where pipes cannot be connected to the stack it may be possible to route a dedicated pipe alongside or in close proximity to the discharge stack.

Termination of discharge pipe

The discharge pipe (D2) from the tundish should terminate in a safe place where there is no risk to persons in the vicinity of the discharge.

Examples of acceptable discharge arrangements are:

• To a trapped gully with the end of the pipe below a fixed grating and above the water seal.
• Downward discharges at low level - i.e. up to 100mm above external surfaces such as car parks, hard standings, grassed areas are acceptable providing that a wire cage or similar guard is positioned to prevent contact, whilst maintaining visibility.
• Discharges at a high level - e.g. into a metal hopper and metal downpipe with the end of the discharge pipe clearly visible or onto a roof capable of withstanding high-temperature discharges of water and 3 m from any plastic guttering system that would collect such discharges.

Termination of condensate hose

The head unit will discharge approximately 0.75L of water per hour under typical operating conditions. This water can be discharged into a grey water drain pipe, D2 of the tundish pipe work, or into a soil pipe.

Considerations should be made with any of these installation methods:

• If discharging into any kind of drain pipe, foul odours can rise through the hose and into the head. This can be controlled by using a U-bend. However, it should be noted that the outlet of the U-bend MUST be below the inlet to avoid water backing up into the head unit.
• When discharging into D2 of the tundish pipework, a swept tee should be used to reduce the possibility of any tundish discharge travelling up the condensate drain hose.
• Consideration should also be made towards the outlet area of the tundish pipework. Some installations may not be suitable for continuous discharge.

Commissioning

All factory-fitted valves etc. are fitted using a thread sealant. If this seal is broken it should be re-sealed using a suitable sealant. It is the installer’s responsibility to ensure all the connections are watertight prior to leaving the property.

1. Ensure the drain on the cold feed pipework is
2. Open a hot tap the furthest distance from the
3. Gradually open the cold mains isolator valve and fill cylinder until water appears at the hot tap. Attend to each hot water outlet in turn and ensure water flow is obtained at each outlet expelling any air within the Once finished, close all hot outlets to build pressure.
4. Locate the bleed valve on the head unit (highlighted in red below), and loosen the black cap by turning it counter-clockwise. Air should hiss from the valve and stop after a few seconds.
5. Re-tighten the auto air vent Failure to replace/re-tighten the auto air vent cap may result in a leaking air vent after extended periods of time. Leaving the auto air vent open will void the warranty of the head unit. It is the installer's responsibility to ensure the cap of the auto air vent is tightened before leaving the property.
6. To ensure the safety valves are operating correctly, turn the tops of the valves independently to ensure water passes through the valve and into the tundish. Once this is confirmed, open both valves together allowing as much water as possible to flow through the tundish. At this point make sure that your discharge pipework is free from debris and is transporting the water away to waste The valves can then be released and a check should be made to ensure they have re-seated correctly.
7. Switch on the Mixergy iHP cylinder and check for correct operation. Mixergy cylinders come supplied in ‘eco mode’ which is designed to satisfy the minimum charge requirements of BS EN 16147:2017 M draw profile. Pressing any button on the gauge twice will exit eco mode.
8. Pair the cylinder to the included powerline adapter to connect it to the Internet. For more information on pairing the cylinder to the adapter, see the commissioning section.
9. Furnish the Customer with the Mixergy iHP User Guide included with the cylinder and direct them to the “Getting started with your Mixergy iHP” video on YouTube.

Changing heat sources

All Mixergy systems leave the factory in full circulation mode. If you wish to enable top-up mode, this can be achieved in a number of ways:

1. In the case where the cylinder has been commissioned and an internet connection has been established, the heating mode can be changed by the installer using the Mixergy Enterprise Installer app or by the user via the standard Mixergy app.
2. In the case where an internet connection cannot be made to the cylinder during commissioning, the heating mode can be set by holding the boost UP and boost DOWN buttons simultaneously. The display will light white to acknowledge that you have entered this mode. To change the heat source, let go of the buttons once any of the display LEDs has changed to the required colour (BLUE for Full Circulation, RED for top-up). The display will then flash either blue, red or green to indicate the new default heat source. Switch the cylinder off and on (power cycle) for the change to take effect.

Status LED error codes

If the system is not behaving as expected, please check the status LED on the side of the controller enclosure and contact Mixergy:

• Flashing green: system OK
• Solid green/red: system updating (DO NOT REMOVE POWER)
• Very slow flashing red (once every two seconds): sensor problem
• Slow flashing red (once a second): no gauge detected
• Fast flashing red (twice a second): energy measurement issue
• Very fast flashing red (five times a second): main processor issue

Pairing the cylinder and connecting to the internet

In the case that the cylinder does not automatically pair to the powerline adapter or connection to an existing homeplug AV network is desired, please follow the steps below to pair the cylinder to the network.

1. Use a thin tool to depress and hold the pair button for 1 - 2
2. Depress the pair button on the powerline adapter for 1-2 seconds within 2 minutes of step 2.
3. Observe all 3 LEDs as solid green on the powerline

Problem-solving

Overheated water

In the unlikely event of overheated (95°C) water being discharged, the Mixergy controller should be switched off immediately and a competent engineer called out. Please contact Mixergy directly.

Water discharge

If water is occasionally being discharged during heating, this likely indicates that the Expansion Vessel needs to be recharged. In the event of this occurring, switch off all power supplies to the cylinder, and re-charge the vessel. If water is continually being discharged, firstly check with a gauge that the pressure allowed through the PRV does not exceed 3 bar. If it does exceed 3 bar then the valve should be stripped, cleaned and inspected. Should a replacement be required then only one supplied by Mixergy should be used.

Electrical fault

If an electrical fault of the controller is suspected or the electrical system does not operate as expected, please contact Mixergy directly.

Connectivity issues

If a connectivity issue is suspected, please refer to the Mixergy iHP User Guide and FAQs for guidance.

Expansion vessel check and re-charging

Check pressure via the Schrader valve on top of the vessel which is situated under the removable plastic cap. The vessel can be checked and recharged by switching off the stopcock or isolating the water supply to the cylinder, then opening a hot tap to deplete the pressure inside the cylinder. Unscrew the black plastic cap on the expansion vessel to reveal the Schrader valve, with the aid of a pressure gauge ensure the pressure reads 3.0 bar. If there is insufficient pressure within the vessel, top up the vessel via a pump and recharge to 3.0 bar. A small amount of water may be discharged when connecting to the Schrader valve. This is due to condensation being trapped when pressurising the expansion vessel.

Safety valves

If all previous checks have been done and water is still being discharged from either safety valve, determine which valve is faulty and replace with one supplied by Mixergy.

Crossflow

If all the valves have been replaced and the vessel re-commissioned, then the system could be suffering from cross-flow. This is when the hot and cold systems are not balanced and higher pressure cold water is forced back into the cylinder. If this is the case, then an additional pressure reducing valve may be required to reduce the cold water supply pressure.

Immersion heaters

If the immersion heater is not heating the water adequately it has either failed (in which case a replacement immersion heater as supplied by Mixergy should be fitted), an electrical fault is present or the electrical cut-out has operated due to the control thermostat being set too low or being faulty. Activate the reset button under the immersion cover. If the problem persists please contact Mixergy directly.

Draining the cylinder

1.  Switch off the immersion heater(s) and any other heat sources.
2. Switch off the water at the mains.
3. Open nearest hot tap.
4. Open drain to start draining the

To re-fill follow the commissioning instructions.

Flushing the cylinder

To flush out the system, drain the unit as above, fill and repeat.

If the cylinder is still discharging after recharging the expansion vessel, it may be due to cross-flow. Ensure appropriate check valves are fitted. The pressure-reducing valve, one of the relief valves, or the expansion vessel may have failed. The component should be identified and replaced by one supplied by Mixergy.

Replacement parts

Do not attempt to repair or replace any parts of the Mixergy cylinder unless you are a trained operative. If you suspect a fault or a replacement part is needed, please contact Mixergy directly.

To determine the correct parts for your system, please ensure you have your cylinder MX number which can be found on the nameplate located at the front of the cylinder.

Servicing and Maintenance

Annual Maintenance

All annual maintenance and service checks should be performed by a competent operative.

If this system is not protected under an active Mixergy Care subscription, failure to maintain this system in accordance with these instructions will invalidate the manufacturer’s warranty.

A maintenance record should be kept. We would recommend either a Mixergy Care subscription or a third party service program is arranged on installation of the cylinder.

Annual service checks

• Expansion relief valve - manually open the twist cap and check that the water is discharged and runs clearly through the Tundish and out at the final discharge point. Ensure that the valve re- seats/re-seals itself.
• Pressure&temperaturereliefvalve-repeattheaboveEnsure that the valve re-seats/re-seals itself.
• Strainer—Turn off the mains. There will be a small amount of residual water in the pipework. Remove the cartridge from the Pressure-Reducing Valve, clean the Strainer, and replace it.
• Expansion vessel - check pressure via the valve on top of the vessel which is located under the plastic cap. Ensure pressure is 3 Bar. Vessel can be recharged if required as per 'Expansion vessel check and re-charging' section
• Head unit - Remove the top cover and blow out the radiator with compressed air to remove dust/debris buildup.

Disassociating an account

If a new tenant is moving into the property and the user of the account tied to the cylinder needs to be changed, the new tenant will have to disassociate the cylinder from the existing account before registering. This can be performed by pressing and holding the boost down and power buttons for approximately 15 seconds.

De-scaling loop

Occasionally, the Mixergy iHP may need the top-up loop de-scaling. The Mixergy iHP is fitted with two 1/2” BSP isolation valves for this purpose, one below the circulation pump (2, please see diagram) and the other is below the 3-way motorised valve (1) on the top-up return pipe.

1. To de-scale the unit, first boost the unit at the gauge to put the iHP into the top-up mode, and disconnect the iHP from the mains electricity. This will fix the valve in the top-up position while de- scaling takes place.
2. Close isolation valves (3) and (4) to isolate the de-scaling loop from the rest of the tank.
3. Connect a reservoir and pump to the two isolation valves (5) and (6).
4. Open isolation valves (5) and (6).
5. Pump de-scaling fluid through the loop for an
6. Drain the de-scaling fluid from the loop and flush with water for a further 5 minutes to ensure all the de-scaling fluid has been
7. Close isolation valves (5) and (6) and open isolation valves (3) and (4).
8. Remove the de-scaling pump and reservoir and ensure isolation valves (5) and (6) are not leaking.
9. The de-scaling procedure is now complete.