LOCATION OF CONTROLS
THERMOSTAT (1)
On/Off Models
109 On/Off type water heaters are fitted with a Honeywell L4189A2014B mechanical thermostat with its sensor located in the inlet side of the water heater header.
147 On/Off type water heaters are fitted with an AKO 14123 electronic thermostat with its sensor located in the inlet side of the water heater header.
On/Off type controls are typically 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.
Hi/Lo Models
109 Hi/Lo type water heaters a fitted with an IMT TRZ 2 stage mechanical thermostat with its sensor located in the outlet side of the water heater header.
147 Hi/Lo type water heaters a fitted with a Campini CTX032Y01 2 stage electronic thermostat with its sensor located in the outlet side of the water heater header.
Hi/Lo type controls are typically used where the system load is variable (e.g. hot water supplying radiator coils for room heating).
GAS CONTROL (2)
On/Off Models
109 On/Off type water heaters are fitted with a White Rodgers 36G22 Type 210 single stage gas valve.
147 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.
Hi/Lo Models
109 and 147 Hi/Lo type water heaters are fitted with a White Rodgers 36E20 Type 301 two stage gas valve.
RATING LABEL (3)
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 (4)
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.
29
