25
LOCATION OF CONTROLS
THERMOSTAT
On/Off Models
On/Off type water heaters are fitted with an Eliwell IC902 electronic
thermostat (Item 1 in the diagram) with its sensor located in the inlet
side of the water heater header. This type of control is used where the
system load is constant (e.g. hot water supplied from a storage tank or
in floor slab heating).
NOTE:
If the water heater is connected to a storage tank with a tank
thermostat fitted, the water heater thermostat should be set slightly
higher than the tank thermostat setting
Modulating Models
For Modulating Models, temperature control is performed by the gas
control which has its sensor located in the outlet side of the water heater
header (see below).
GAS CONTROL (ITEM 2 IN THE DIAGRAM)
On/Off Models
On/Off type water heaters are fitted with a Honeywell SV9605 smart valve. This gas control incorporates the
ignition electronics and provides the gas supply to the pilot and main burners.
Modulating Models
Modulating type water heaters are fitted with a Robertshaw 7000 series modulating gas control. The gas control
modulates the gas rate to match the required heating load. Modulating water heaters are usually installed on a
heating system with radiators or a fan coil.
RATING LABEL (ITEM 3 IN THE DIAGRAM)
Details the model number, serial number, gas type, burner pressure, water pressure and electrical specifications of
the water heater are given on this label.
HIGH LIMIT (ITEM 4 IN THE DIAGRAM)
A manual reset over temperature switch which will shut down the water heater in the event of a fault with the
temperature control or water flow. When the system water temperature has cooled sufficiently the high limit can be
reset by pressing the red button.
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Summary of Contents for B0200
Page 22: ...CONNECTIONS ELECTRICAL 22 WIRING DIAGRAM ON OFF MODELS...
Page 23: ...CONNECTIONS ELECTRICAL 23 WIRING DIAGRAM MODULATING MODELS...
Page 31: ...TEMPERATURE CONTROL 31...
Page 36: ...36 This page is intentionally blank...
Page 37: ...37 This page is intentionally blank...
