Hot Water Mode:
The appliance operates to supply only domestic hot water when the heating temperature mode is fully
A flow restrictor is fitted within the appliance which limits a hot water delivery rate to a maximum of:
24CDi | 9.0 (±15%) litres/minute |
28CDi | 10.0 (±15%) litres/minute |
35CDi II 12.0 (±15%) litres/minute
Hot Water and Central Heating mode:
Fig. 1. System Diagram.
Automatic air |
| |
vent |
| |
| Gas to water | |
| heat exchang- | |
| er | |
| Boiler | |
Circulating | Expansion | |
pump | ||
| vessel | |
Water to | Pressure | |
water heat | ||
relief valve | ||
exchanger | ||
| ||
Diverter valve |
|
CH | Domestic | Domestic CH | Safety dis- |
flow | hot water | cold sup- return | charge |
| out | ply |
|
When a demand is made for heating by the system con- trols (i.e. a programmer or room thermostat), the pump will energise, circulating pri- mary water around the heat- ing system and the burner will light. The heat output from the appliance in this mode has been factory set to maximum. The appliance will operate as necessary to main- tain the temperature of the radiators at the level set by the adjustment of the Heating Temperature Control Knob. (See Fig. 2.)
If the system no longer requires output to maintain the desired room tempera- ture, the burner will extin- guish. The pump will contin- ue to run for a short period to dissipate the residual heat from the appliance and then switch off.
The appliance will sup- ply heat to the central heating system as required. A demand for hot water at a tap or show- er will override the central heating function for the peri- od of the domestic hot water demand.
4
