The DIGI Camper

Introduction

The Camper is so named because it was originally designed for fitting external to holiday homes on a campsite.

The unit is designed for situations where there is little or no room in the property for the heat interface unit, so it must be placed outside. It therefore comes complete with a casing specifically designed and insulated to cope with the most extreme weather conditions.

The casing is manufactured in fibreglass with a gel-coat finish that can be coloured to match the properties on site, and each case is equipped with two lockable compartments. The upper compartment houses the Heat Interface Unit, and the lower compartment houses the service valves, and spaces the unit off the ground to avoid any risk from flooding.

Internally the unit is essentially a 'DIGI' HIU utilising a plate heat exchanger for hydraulic separation of the district heating network and the heating system within the property, with another plate heat exchanger used for generation of domestic hot water.

With the exception of the expansion vessel and filling loop for the central heating, the unit provides all the controls required.

Installation Instructions

DIGI Installation Instructions

Component Instructions

The Camper unit may be fitted with either a Double Regulating Valve, or a Pressure Independent Control valve and actuator (see Items 3, 20 and 21 in the 'Components' section below) . Both valves can be adjusted to regulate the flow rate to the heating circuit following the instructions below.

Some HIU's may also be fitted with an AB-QM Bypass valve (Item 8), this allows a small flow from the primary system to flow up to the HIU without entering the HIU or affecting the energy consumption. This valve is simply to maintain flow on the primary system and to speed up the HIU's response to a hot water demand.

Double Regulating Valve Instructions

AB-QM Adjustment Instructions

HIU's may also be fitted with a landlord security solenoid valve (Item 9), to enable remote isolation of the unit. This valve is powered open, and therefore when power to the HIU is isolated it will close and stop district heating flow into the unit.

Each HIU is fitted with an Energy Meter / Heat Meter, which measures the amount of energy / heat consumed by the unit by metering the primary system flow rate, and its respective flow and return temperatures. This enables the site manager to obtain an energy reading which can be used for billing individual users.

The DIGI Camper HIU is fitted with a Kamstrup Multi-Cal 402 heat meter.

Kamstrup Multical 402 User Guide

Key Features

• Colour coordinated fibreglass casing, with lockable hinged doors
• 30mm Expanded Polypropylene (EPP) insulated secondary case
• Stepper motor control valves as standard
• Option for pressure independent high flow control valves
• Built-in pump
• Allowance for any industry standard heat meter
• Standardised, documented, controls layouts
• Isolation of central heating circuit from heat network
• Provision for flooding to a depth of 600mm
• Primary system bypass to allow flow up to the unit at all times (External to the meter circuit)
• DN25 Copper Pipework
• Safety relief valve
• Drain cocks on both primary and secondary circuits
• Isolation valves
• Dimensions 1405 x 800 x 400mm

Options

• Heat meter fitted within casing
• Expansion vessel within casing
• Filling Loop and pressure gauge within casing

Connections

Components

Installation of Heat Meter

Important Note: On the Digi HIU the Heat Meter is fitted on the flow.

• Option 1: Standard Immersion Sensor
• Option 2: 1/2" Pocket

Solenoid Security Valve

EV250B Solenoid

The Danfoss EV250B Solenoid Valve is used as a security isolation valve, to be wired to a billing system. The purpose of the valve is to close the primary supply on loss of credit, preventing further production of hot water and central heating, until allowed by the billing system.

EV250B with assisted lift can operate from zero and up to 10 bar differential pressure. This 2/2-way valve program is especially to use in closed circuits with low differential pressure, but demanding moderate flow rates. Valve body in dezincification resistant brass for ensuring a long life even in connection with aggressive steam media. EV250B is compatible with the broad Danfoss coil program with enclosures from IP00 up to IP67. Medium temperatures up to 140°C (low pressure steam).

• For water, oil, compressed air and similar neutral media
• Flow range: 0.5 - 20 m3/h
• Differential pressure: 0 - 10 bar
• Media temperature from -30 - 140 °C
• Ambient temperature: Up to 80 °C
• Coil enclosure: Up to IP67
• Thread connections: From Gâ…œ - G1
• DN 10 - 22
• Viscosity: Up to 50 cst
• The valve can be used for rough vacuum
• Water hammer damped
• DZR brass version in NC and NO

Commissioning

Follow these steps for the commissioning of the HIU. In case of leaks or other abnormalities, please refer to the chapter on Fault Finding.

• Close all water outlets in the house.
• Check all nuts for tightness.
• Make sure that the electronics housing is in place and the cables do not obstruct the cover when it is closed.
• Slowly turn on the mains water supply and check the set for leaks.
• Open the central heating isolating valves.
• Check the air vent on the heating circuit within the HIU is not capped.
• Connect the central heating filling loop (by installer) and fill the central heating circuit to 1.5 bar, checking for leaks.
• Check both isolating valves are closed
• Carefully remove caps, expecting some drips
• Connect filling loop
• Open the system side isolating valve fully
• Open mains isolating valve slowly until the pressure on the gauge starts rising
• When the pressure has reached 1.5 bar, close the mains isolating valve
• Close the system isolating valve
• Disconnect the filling loop, catching the water from within the hose
• Replace the caps
• Turn on power to the system. The LED should flash green.
• Turn on power to the Billing System. There will need to be sufficient credit on the system to open the security valve and allow flow to the HIU for commissioning. Please contact the billing system provider for further assistance if required.
• Slowly open the district heating supply and check the set for leaks.
• Slowly open a hot water faucet. Check during this step continuously or the LED indicator (C) of the electronics blue flashes. Open the tap completely once all the air is out of the pipe and let it stand for 5 minutes open. Check between 3 and 5 minutes the water at 57°C - 60°C.
• Close the water tap. The LED flashes green.
• Turn on the central heating using the programmer and room thermostat (turned up) installed elsewhere in the property. The central heating pump will start to run, clearing air through pipework towards radiators.
• Bleed the central heating system, keeping an eye on the system pressure. Start with lowest and finish at highest radiator.
• Leave the central heating on for 5 minutes and confirm heat is supplied to radiators.
• With the central heating on, check the primary flow rate using the heat meter display, and if required adjust the flow using the central heating regulating valve until the design flow for the property is achieved.
• With the central heating on, record the following data from the heat meter on the commissioning sheet:
  • flow rate [m3/h]
  • primary flow temperature [°C]
  • primary return temperature [°C]
• Turn off the central heating and record the following data from the heat meter on the commissioning sheet:
  • energy use to date [kWh]
  • model and part code
  • serial number
• Where appropriate, check the figure for the energy use matches that provided on the billing system display.
• Cap the automatic air vent for the central heating.
• Fit internal HIU insulation cover, using the blue security washers provided.
• Fit external HIU casing, and retain using security bolt.
• Central heating circuits should be protected with a suitable corrosion inhibitor. The procedure for doing this will depend upon the type of inhibitor, with the most common method been to inject inhibitor via a radiator.

Maintenance and Servicing

Annual Checks

Central Heating Pressure

• Check pressure in central heating system is between 1.2 bar and 2.5 bar.
• Fill as required.
• Check both isolating valves are closed
• Carefully remove caps, expecting some drips
• Connect filling loop
• Open the system side isolating valve fully
• Open mains isolating valve slowly until the pressure on the gauge starts rising
• When the pressure has reached 1.5 bar, close the mains isolating valve
• Close the system isolating valve
• Disconnect the filling loop, catching the water from within the hose
• Replace the caps

Strainers

• Isolate all connections.
• Where a drain cock is provided drain water from HIU.
• Using an adjustable spanner, loosen the cap from the strainer, being careful to catch any discharged water.
• Remove the filter, clean and replace.
• Replace cap, and tighten.
• Repeat for all strainers (primary, mains, and central heating).
• Open all isolating valves carefully, checking for leaks.

Every 5 Years

• Recallibrate or Replace heat meter (must be performed by approved engineer)

Corrosion Inhibitor

Please refer to guidelines provided by the supplier of the chosen corrosion inhibitor as to the frequency and method of re-dosing the system. Always leave a record with system, typically using label provided with inhibitor.

User Guide

Application

The Thermal Integration Ether is used to generate hot water and central heating from a heat distribution systems.

The HIU should be installed under the following conditions:

• HIU should be installed degree in a frost-free area
• HIU should not be exposed to direct sunlight.
• Ambient temperature: 5°C to 40°C
• Humidity range: 10% - 85%

LED Status Indicators

The system provides an LED indication of its current status.

• Green flashing: Normal operation
• Blue flashing: Tapping operation
• Red flashing: Failure
• White continues: Service mode (for installers only)
• No light: Power is off

Operation

The differential pressure controller regulates the differential pressure across the heating system keeping it constant regardless of flow rate. This differential in pressure causes the flow of heat from the distribution network through the heating system. The heating system controls provided in the property determine how much heat is provided to each room.

The HIU is equipped with a copper brazed, double-walled plate heat exchanger. It is comprised of numerous plates of metal, through which heat is transferred from hotter water to colder water, with total hydraulic separation. A double-walled plate heat exchanger has an air gap between each of the hydraulic circuits so that in the event of a plate rupture, the hydraulic circuits remain separated to avoid the risk of contamination of the potable water.

Economy / Comfort Mode

It is common for HIUs to include a thermostatic bypass to maintain Domestic Hot Water temperatures at all times, and prevent delays in hot water supply. The CAMPER HIU performs a similar function, momentarily opening the Domestic Hot Water stepper motor slightly to allow small quantities of primary water to enter the unit at regular intervals. The CAMPER will creep primary water into the unit ensuring that return temperatures remain below the Domestic Hot Water setpoint. The primary pipework usually loses heat faster than the CAMPER's casing, hence the unit will typically settle trickling in heat fast enough to keep the primary flow at Domestic Hot Water temperature. The CAMPER (and our range of electronic HIU's) are the only HIU's capable of this level of control, ensuring low return temperatures at all times.

In addition, the CAMPER provides an option that can be setup during commissioning to keep the Domestic Hot Water up to temperature continuously, or to allow it to go cold after a specified time of inactivity. This option is desirable when the heat loss of the HIU and its pipework is greater than the perceived down-side of a longer delay during the first morning, or evening draw-off.

The CAMPER uses an electronically controlled valve and flow sensor. During hot water demand the flow sensor will detect the draw-off rate and convey this to the electronic control. This ensures optimum opening of the valve, thus obtaining a water temperature of 60°C.

While hot taps are running the system provides hot water priority, closing off the supply to the central heating. When tapping stops the heat supply resumed to the heating circuit.