Central Heating Twin Coil Hot Water Cylinder Installation Guide

: September 18, 2024
: Central Heating

Table of Contents

Central Heating Twin Coil Hot Water Cylinder
Product Usage Instructions
FAQ
Installation
Setting
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Central Heating Twin Coil Hot Water Cylinder

Specifications:

Product: Twin Coil Cylinder
Capacity: 300L
Heating Element: 2.7kW
Coils: Twin Coil
Thermostat Type: Indirect Thermostat (Discard if not required)
Additional Features: Probe Pocket for DHW sensor

Product Usage Instructions

Twin Coil Cylinder Installation:

Ensure both coils are used when heating with a heat pump for optimal performance.
Move the 2.7kW element to the lower housing and the probe pocket to the upper housing.
Discard the indirect thermostat and solar thermostat if not required.
Wire the element through a local isolation point and a time clock.

Twin Coil Cylinder Thermostat Setting:
Set the element thermostat in the lower housing to ensure complete heating of the tank.

Twin Coil Cylinder Wiring Instructions:

Heat Source with Probe:

Wire the 10K NTC sensor to the heat source.
Move the element control stat to the bottom port on the cylinder.

Heat Source Without Probe:

Wire the On/Off signal from the time clock through the Indirect Thermal Cut Out and Indirect Thermostat.
Use a time clock to schedule hot water production.

FAQ

Q: Can the indirect thermostat and solar thermostat be removed?
A: Yes, if not required, both thermostats can be discarded following the installation instructions.

Installation

When heating a 300L twin coil HWC with a heat pump, both coils are used to maximize system performance and reduce pressure drop. The element in the cylinder is then only required to be run once a day or once a week for anti- legionella protection as per the requirements of G12. While the element is factory it is installed in the upper housing, in most scenarios is best for this to be located in the lower housing. Please move the items as per diagram 1 & 2 along with the following instructions.

Please Note: The element should be installed in the downwards-facing position as shown in diagram 2 to ensure complete heating of the tank.

2.7kW Element = move to lower housing
Probe Pocket = move to the upper housing
Indirect Thermostat = discard as not required
Solar Thermostat = discard as not required
Element Thermostat = move to lower housing

The element (now located in the lower housing)has a spare probe pocket for the heat pump’s DHWs sensor to be installed. The element should be hired through a local isolation point and a local or whiteboard-mounted time clock (supplied by others).

Setting

Heat Source with Probe
When installing a twin coil cylinder on a heat source that can wire a DHW sensor into it such s our air-to-water heat pumps, the cylinder should be wired as per diagram 3 with the element control stat moved to the bottom port on the cylinder. As noted, the boiler control thermostat is not required. This along with its capillaries can be removed and discarded. Where the heat source cannot heat the HWC above 60°C as required for legionella prevention, we recommend the element is wired through a time clock.

10K NTC Sensor Wired to Heat Source
Power Supply
Dual Probe Pocket
Boiler Control Stat (Not Required)
Element Control Stat with Capillary

Heat Source Without Probe
When installing a twin coil cylinder on a heat source that cannot be wired with a DHW sensor, the Signal from the HWC will need to be wired through the Indirect Thermal Cut Out and Indirect Thermostat as shown in diagram 4. Typically, this demand signal to turn the heat source on (and open a zone valve) would be wired through a time clock to schedule hot water production. Where the heat source cannot heat the HWC above 60°C as required for legionella prevention, we recommend the element is wired through a time clock.