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Gas HeatGas Heat

THERMOSTATSTHERMOSTATS

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ThermostatThermostat

• A thermostat is a control that is activated by changes in the surrounding air temp.

• A thermostat is a control that is activated by changes in the surrounding air temp.

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Mercury thermostatMercury thermostat

• Has mercury inside which is considered a hazardous material which.

• Mercury was used because it stays liquid at room temperature.

• Not as sensitive as a programmable.

• Has a heat anticipator.

• Can only set 1 temperature at a time.

• Has mercury inside which is considered a hazardous material which.

• Mercury was used because it stays liquid at room temperature.

• Not as sensitive as a programmable.

• Has a heat anticipator.

• Can only set 1 temperature at a time.

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Mercury Bulb ThermostatMercury Bulb Thermostat

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Snap Action ThermostatSnap Action Thermostat

No mercury.

Inexpensive.

Accurate, but not as sensitive as a digital thermostat.

Has a heat anticipator.

Can only set 1 temperature at a time.

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Snap Action ThermostatSnap Action Thermostat

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Digital ThermostatsDigital Thermostats

• No mercury inside.

• Operated by a circuit board and sensor.

• More sensitive to temperature change- up to ½ a degree.

• Depending on the brand and model of t-stat being installed, you can set more then 1 temperature.

• No mercury inside.

• Operated by a circuit board and sensor.

• More sensitive to temperature change- up to ½ a degree.

• Depending on the brand and model of t-stat being installed, you can set more then 1 temperature.

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Common wiring terminals on all basic thermostatsCommon wiring terminals on all basic thermostats• RC = 24v power for cooling• RH = 24v power for heating• Y = cool• W= heat• G = blower

• RC = 24v power for cooling• RH = 24v power for heating• Y = cool• W= heat• G = blower

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Common wiring terminals on all higher end thermostatsCommon wiring terminals on all higher end thermostats• RC/RH= power (24v)• Y1= stage 1 cool• Y2= stage 2 cool• W1= stage 1 heat• W2= stage 2 heat• G=fan • O= reversing valve ( found on heat pumps)• C= common

• RC/RH= power (24v)• Y1= stage 1 cool• Y2= stage 2 cool• W1= stage 1 heat• W2= stage 2 heat• G=fan • O= reversing valve ( found on heat pumps)• C= common

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Common wire colors used for wiring componentsCommon wire colors used for wiring components• RC/RH = Power (24v) = red• G = Fan= green• Y1 = stage 1 cool= yellow• Y2= stage 2 cool= blue• W1= stage 1 heat= white• W2= stage 2 heat= brown• O- reversing valve= orange• C = Common= black

• RC/RH = Power (24v) = red• G = Fan= green• Y1 = stage 1 cool= yellow• Y2= stage 2 cool= blue• W1= stage 1 heat= white• W2= stage 2 heat= brown• O- reversing valve= orange• C = Common= black

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Heat anticipator Heat anticipator

• A device that will shut down the heating circuit, prematurely of the set point, so the system does not over shoot the set-point temperature.

• The set-point is the temperature the thermostat is set too.

• A device that will shut down the heating circuit, prematurely of the set point, so the system does not over shoot the set-point temperature.

• The set-point is the temperature the thermostat is set too.

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Setting a heat anticipatorSetting a heat anticipator

• Take your meter to the t-stat and set it to amps.

– Jump out your heating circuit (R and W)– Wrap your jumper around your amp probe 10 times– Read your meter and divide by 10– This is your heat anticipator set-point

• Sometimes this information can be written on unit information sticker.

• Take your meter to the t-stat and set it to amps.

– Jump out your heating circuit (R and W)– Wrap your jumper around your amp probe 10 times– Read your meter and divide by 10– This is your heat anticipator set-point

• Sometimes this information can be written on unit information sticker.

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SymbolsSymbols

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