ALC ASTAT503-1 Outdoor Thermostat Low Ambient Control Kit Instruction Manual

ALC ASTAT503-1 Outdoor Thermostat Low Ambient Control Kit

Product Information

• Product Name: Fossil Fuel Kit AFOSL500-1/1.841185
• Product Type: Fossil Fuel Kit
• Manufacturer: ALCenonmoxfIontretr-nAAa.tiAiro.eCn.a/l CInce.nCtoumrpyany
• Model Number: AFOSL500-1/1.841185

Product Usage Instructions

1. Installation should only be carried out by trained and qualified service personnel to ensure safety and prevent property damage, personal injury, or death.
2. Prior to installation or servicing, ensure that all power to the unit is turned off to avoid the risk of electrical shock. Multiple disconnect switches may be present.
3. Exercise caution when handling the equipment to avoid personal injury from sharp metal edges.
4. The Fossil Fuel Kit AFOSL500-1/1.841185 can be used in conjunction with the Outdoor Thermostat/Low Ambient Control Kit ASTAT503-1/1.841188 or in electric heat and/or heat pump applications.
5. The outdoor thermostat can be set to deactivate the heat pump at a user-selected set point and utilize electric heat or fossil fuel furnace heat (depending on the application) when the outdoor ambient temperatures fall below the selected set point.
6. The outdoor thermostat delays electric heat operation until it is necessary, maximizing the load on the heat pump in the pump applications or keeping the heating load on low power for as long as possible in straight electric heat applications.
7. Consider heat loss calculations, equipment size, and balance points when determining the proper outdoor temperature at which the calculated structural heat loss matches the heating capacity of the unit (balance point). Set the outdoor thermostat at the balance point when an additional stage of heat is required to maintain the indoor design temperature.
8. During a heat pump defrost cycle, electric heat must be energized to temper the indoor air. In heat pump applications, wire only part of the elements through the outdoor thermostat. If all elements are controlled through the outdoor thermostat, adjust the set point above the ambient temperature where defrosting occurs.
9. The Fossil Fuel Kit AFOSL500-1/1.841185 features the ability to complete the 1st stage call for heat even after the 2nd stage of the thermostat is satisfied. This allows the furnace to reach its optimum efficiency. Subsequent cycle calls for heat will begin with the heat pump’s 1st stage unless the ambient temperature is below the outdoor thermostat’s set point.

INSTALLATION INSTRUCTIONS

WARNING

• Installation and servicing of air conditioning equipment can be hazardous due to internal refrigerant pressure and live electrical compo-nents. Only trained and qualified service personnel should install or service this equip-ment. Installation and service performed by unqualified persons can result in property damage, personal injury, or death.
• Risk of electrical shock. Before installing or servicing unit, be sure ALL power to the unit is OFF. More than one disconnect switch may be present. Failure to disconnect power supplies can result in property damage, personal injury, or death.
• As with any mechanical equipment, personal injury can result from contact with sharp metal edges. Be careful when handling equipment.

General

Fossil fuel kit AFOSL500-1/1.841185 is recommended for use with heat pumps in combination with a fossil fuel (gas or oil) furnace. The fossil fuel kit, when used in conjunction with outdoor thermostat ASTAT503-1/1.841188, can be used to switch from heat pump to fossil fuel furnace operation and to control the point at which the heat pump operation will be switched to fossil fuel furnace operation. The fossil fuel kit can be used with single or two-stage fossil fuel furnaces (including variable speed) as well as single or two-stage heat pumps. Outdoor thermostat/low ambient control ASTAT503-1/1.841188 can be used with fossil fuel kit AFOSL500-1/1.841185 as described above or in electric heat and/or heat pump applications. The outdoor thermostat can be set to deactivate the heat pump at a user-selected set point and satisfy the heat call only with electric heat (or fossil fuel furnace heat, depending on the application) at outdoor ambient temperatures below the selected set point.

Operation Description

AFOSL500-1/1.841185 Fossil Fuel Kit

• On heat demand, the 1st stage of the thermostat closes and energizes the heat pump operation. The heat pump will continue to operate until the 1st stage heat demand is satisfied. If the heat pump is operating below the balance point and cannot satisfy the heat load, the thermostat will switch to 2nd stage. The heat pump will be de-energized and the furnace will energize. Once 2nd stage has been satisfied, the unit will continue to run in the furnace mode until the 1st stage heat demand has also been satisfied. Upon the next call for heat, the heat pump operation will resume as outlined above.

AFOSL500-1/1.841185 Fossil Fuel Kit with ASTAT503-1/1.841188 Outdoor Thermostat

• An outdoor thermostat can be used to optimize the performance of a dual-fuel system based on fuel cost vs. heat load. Above the adjustable set point, the system operates as outlined above in

AFOSL500-1/1.841185 Fossil Fuel Kit.

• Below the set point, the outdoor thermostat locks out the heat pump operation and switches the furnace operation to 1st stage of the thermostat. When outdoor temperature rises to above the set point, normal heat pump operation is resumed.
• This system can be tailored for most efficient operation relative to local fuel cost.

ASTAT503-1/1.841188 Outdoor Thermo-stat/Low Ambient Control

• The outdoor thermostat delays electric heat operation until it is necessary. In heat pump applications, the outdoor thermostat keeps the load on the heat pump as long as possible. In straight electric heat applications, the outdoor thermostat keeps the heating load on low power as long as possible.
• Heat loss calculations of the house or structure, equipment size, and balance points must be considered when determining the proper outdoor temperature at which the calculated structural heat loss exactly matches the heating capacity of the unit which is the balance point. The outdoor thermostat should be set at the balance point when an additional stage of heat is required to maintain the indoor design temperature.
  NOTE : Electric heat must be energized during a heat pump defrost cycle to temper the indoor air. In heat pump applications, wire only part of the elements through the outdoor thermostat or, in cases where all of the elements are controlled through the outdoor thermostat, adjust the outdoor thermostat set point above the ambient temperature where defrosting will occur.

AFOSL500-1/1.841185 Fossil Fuel Kit Features

• Turn off the heat pump when the furnace is operating (except during defrost periods)

• Two-stage heat option – 2nd stage heat call shuts off heat pump, turns on furnace
  NOTE: Once 2nd stage of the thermostat is satisfied, the furnace will remain on and complete the 1st stage call for heat. This allows the furnace to reach its optimum efficiency. The next cycle call for heat will begin with the heat pump 1st stage unless the ambient is below the ODT set point.

• 3-minute timed delay
  Delay is activated during initial power up, loss, and restoration of power, and after all heat pump heat and cool cycles.
  The compressor was prevented from restarting within 3 minutes of an off cycle and on power up.
  NOTE : The unit must be in the thermostat off cycle for at least 3 minutes. If the call is initiated before the 3-minute delay has expired the defrost board will delay the compressor from coming on for 3 minutes. If the call is initiated after the 3-minute off delay has expired the compressor will come on within 5 seconds from the call.

• 5-second debounce on Y, W1, E, and O thermostat inputs must remain at least 5 seconds before the defrost board responds.

• Outdoor thermostat (optional)
  Automatically switches between heat pump and furnace operation at a specific adjustable outdoor ambient set point temperature.
  Fail-safe mode: In the event, that the outdoor thermostat N.O. contacts fail/stick closed, the defrost board will prevent the furnace from being activated by a cooling call.

Installation

WARNING
Risk of electrical shock. Disconnect all power supplies before servicing. More than one disconnect switch may be present. Failure to do so can result in property damage, personal injury, or death.

Mounting Fossil Fuel Kit AFOSL500-1/1.841185

1. Choose a location that will permit mounting the fossil fuel kit near or within the fossil fuel furnace.
2. Using the fossil fuel board as a template, mark the location of the mounting holes.
3. Use screws to mount the fossil fuel kit.

Mounting Outdoor Thermostat ASTAT503-1/1.841188

• Make wiring connections to terminals before mounting the thermostat (see Making Electrical Connections on page 3).
• Electric Heat Only Applications (No Outdoor Unit)
• The thermostat kit must be installed outdoors in the outdoor mounting box ASTATBOX502-1.
• Electric Heat with Condensing Unit Applications
• The thermostat kit may be mounted in the unit compressor compartment if space allows. It is not necessary to route the capillary tube to the outdoor fan section. The compressor will not be operating, so equal temperatures will exist. If space in the compressor compartment is limited, the thermostat may be installed outside of the unit on an adjacent wall using the outdoor mounting box ASTATBOX502-1.

Heat Pump Applications

House the outdoor thermostat in the outdoor mounting box ASTATBOX502-1 and install it outside on an adjacent wall by the outdoor unit.

Installing ASTAT503-1/1.841188 Using Mounting Box ASTATBOX502-1
When the thermostat is installed outside in the mounting box, the mounting box and sensing bulb must be located where they will not be affected by direct sunlight or wind.

1. Remove cover from the thermostat box and insert the thermostat capillary tube through a grommet in the bottom of the box, or leave the capillary tube coiled inside the mounting box.
2. Remove the adjustment knob and securing screws from the thermostat. Insert the thermostat through the back of the mounting box with the shaft extending through the opening. Line up mounting holes and re-install screws. Place the adjustment knob back on the thermostat.
3. Coil excessive capillary tubing or secure with clamps if necessary.

Making Electrical Connections

• All wiring should be done in accordance with the National Electrical Code, ANSI/NFPA No. 70 (latest edition); Canadian Electrical Code Part 1, CSA C22.1 (latest edition); or local codes where they prevail.
• Fossil Fuel Kit AFOSL500-1/1.841185 Connections
• When using outdoor thermostat ASTAT503-1/1.841188 with AFOSL500-1/1.841185 fossil fuel kit, the tab on the fossil fuel kit control board next to the terminal strip for the heat pump field wiring connections must be broken for the outdoor thermostat to function with the fossil fuel kit (see Figure 1 on page 5).
• See Figures 2 and 3 on pages 6 and 7 for fossil fuel kit field wiring connections for furnace (single stage and two stage), heat pump, and thermostat.
• Outdoor Thermostat ASTAT503-1/1.841188 Connections
• Make wiring connections to terminals before mounting the thermostat. Enclose connections where they will not be affected by direct sunlight or wind. Refer to Figure 4 on page 8 for typical thermostat wiring connections. Class 2 type wire may be used for low-voltage wiring.
  NOTE : Emergency heat relay, if used, is field provided.

AFOSL500-1/1.841185 Fossil Fuel Kit Operation
Cooling Call (1st stage)

• On a 1st stage cooling call, the outdoor compressor and fan are energized along with the indoor circulating air fan.

Thermostat Call
Inputs (24VAC)

• R + Y/G/O on T-STAT terminal strip of fossil fuel board

Outputs (24VAC)

• Y terminal of heat pump terminal strip of fossil fuel board energizes outdoor compressor Y (3 minutes off delay after power up and after compressor cycle)
• O terminal of heat pump terminal strip of fossil fuel board energizes outdoor reversing valve. O remains energized as long as the thermostat is in the cool mode.
• G terminal of furnace terminal strip of fossil fuel board energizes G of furnace energizing indoor fan.
• Y terminal of furnace terminal strip of fossil fuel board energizes Y of furnace energizing indoor fan cooling CFM.

Cooling Call (2nd Stage)

• On a 2nd stage cooling call, the outdoor compressor, fan, and indoor fan are switched to Y2 – 2nd stage compressor call and Y2 – 2nd stage indoor fan CFM.

Thermostat Call
Inputs (24VAC)

• R + Y2 on T-STAT terminal strip of fossil fuel board

Outputs (24VAC)

• Y2 terminal of heat pump terminal strip of fossil fuel board energizes outdoor compressor Y2 (if used). Y2 terminal of heat pump terminal strip of fossil fuel board energizes Y2 CFM of the furnace (if used).

Thermostat Removes Call (24VAC)

• R-Y2 = Y2 to furnace (if used) de-energized, Y2 to heat pump (if used) de-energized. The compressor goes back to 1st stage, circulating air blower goes to Y1 CFM.
• R-Y/G = Compressor Y, fan G off. 3-minute delay starts.
• R + O = O remains energized as long as the thermostat is in the cool mode.

Fan On Call

• On a fan on call, the indoor fan is energized.

Thermostat Call
Inputs (24VAC)

• R + G on T-STAT terminal strip of fossil fuel board

Outputs (24VAC)

• G terminal of furnace terminal strip of fossil fuel board energizes G of furnace energizing indoor fan.

Heat Call (1st Stage) without outdoor stat ODT or with outdoor stat ODT when ambient is above ODT set point.
On a 1st stage heat call, the thermostat will energize Y and G to the fossil fuel board, the fossil fuel board will energize the heat pump in the heat mode.

Thermostat Call
Inputs (24VAC)

• R + Y/G on T-STAT terminal strip of fossil fuel board.

Outputs (24VAC)

• Y terminal of heat pump terminal strip of fossil fuel board energizes outdoor compressor Y (3 minutes off delay after power up and after compressor off cycle)
• G terminal of furnace terminal strip of fossil fuel board energizes G of furnace energizing indoor fan on speed.
• Y terminal of furnace terminal strip of fossil fuel board energizes Y of furnace energizing indoor fan on cooling CFM.

Heat Call (2nd stage) without outdoor stat ODT or with outdoor stat ODT when ambient is above ODT set point.
On a 2nd stage heat call, the thermostat will energize W1 to the fossil fuel board, the fossil fuel board will de-energize the heat pump and energize the furnace. Once the 2nd stage heat call is satisfied, the fossil fuel board will keep the furnace on to finish the cycle until 1st stage heat call is satisfied. The next heat call cycle will begin with heat pump again unless an ODT is used and the ambient drops below the outdoor ambient.

Thermostat Call
Inputs (24VAC)

• R + W1 on T-STAT terminal strip of fossil fuel board. R+ Y/G on T-STAT terminal of fossil fuel board remains.

Outputs (24VAC)

• W1 terminal of furnace terminal strip of fossil fuel board energizes W1 of furnace energizing furnace.
• Y/G of furnace terminal strip of fossil fuel board is removed (de-energized).
• Y/G of heat pump terminal strip of fossil fuel board is removed (de-energized).

Heat Call (3rd stage) without outdoor stat ODT or with outdoor stat ODT when ambient is above ODT set point.
NOTE : A three-stage heat thermostat may be used with a two-stage furnace to obtain 2nd stage furnace heat call by demand (see Figure 3 on page 7).

• A 3rd stage call for heat will energize the 2nd stage of the furnace (demand call). The furnace 2nd stage timer function must be disabled (placed in the NONE position) for this feature (if applicable).
• On a thermostat call 3rd stage heat to W2 of the fossil fuel board thermostat terminal strip, W2 of the fossil fuel board furnace terminal strip will energize the 2nd stage heat of the furnace.
• If using ODT and the ambient is below the ODT set point, the 3rd stage will bring on 2nd stage of the furnace if 1st stage does not meet demand.
• Heat Call (2nd stage satisfied) without outdoor stat ODT or with outdoor stat ODT when ambient is above ODT set point.

Outputs (24VAC)

• W1 terminal of thermostat terminal strip of fossil fuel board is removed, Y/G remains.

Heat Call (1st stage satisfied) without outdoor stat ODT or with outdoor stat ODT when ambient is above ODT set point.

Outputs (24VAC)

• Y/G of the thermostat terminal strip of fossil fuel board is removed, furnace cycles off.

Heat Call (1st stage) with outdoor stat ODT, ambient below the set point.
On a 1st stage heating call, the thermostat will energize Y and G to the fossil fuel board. Fossil fuel board and ODT will energize the furnace for heating demand.

Fossil Fuel Kit

Field Wiring Connections
Minimum Thermostat Requirements:

• Heat pump thermostat
• Two-stage heat/single-stage cooling
• Emergency heat function

NOTE
NO/NC position on ODT based on ambient relationship to set point selected: As shown here, ambient is the above-set point.

Thermostat Call
Inputs (24VAC)

• R + Y/G on T-STAT terminal strip of fossil fuel board.

Outputs (24VAC)

• W1 terminal of furnace terminal strip of fossil fuel board energizes W1 of furnace energizing furnace.
• Y/G on the furnace terminal strip of the fossil fuel board is removed by way of ODT ambient switchover temperature.

Fossil Fuel Kit with Single Stage Furnace Wiring Connections

Minimum Thermostat Requirements:

• Heat pump thermostat
• Two-stage heat/single-stage cooling
• Emergency heat function

NOTES

1. See thermostat installation instructions for proper emergency heat connection.
2. WARNING : Certain oil furnaces require connections at pigtail wires, or other thermostat connection points, not at the circuit board. See furnace installation instructions for proper connection requirements. Connections at wrong points may bypass safety controls.
3. Heat pump defrost feature includes a 5-minute compressor-off delay during which the compressor is prevented from restarting within 5 minutes of an off cycle.
4. Compressor prevented from restarting within 3 minutes of an off-cycle or on power up (a feature of fossil fuel board).

Defrost
During a heat pump heating mode run cycle, if the unit has accumulated enough run time and the defrost sensor is closed, the unit will go into defrost mode. The outdoor condenser fan will shut off and the reversing valve will switch over to cooling mode. The furnace will turn on to temper the indoor air.

Inputs (24VAC)

• R + W from outdoor heat pump defrost board to heat pump terminal strip W2 of fossil fuel board.

Outputs (24VAC)

• W1 terminal of furnace terminal strip of fossil fuel board energizes furnace W or W1 for heat call during tempering during defrost mode.

Fossil Fuel Kit with Two Stage Furnace Wiring Connections
Minimum Thermostat Requirements:

Option 1

• Heat pump thermostat
• Two-stage heat/single-stage cooling
• Emergency heat function
• 2nd stage furnace is controlled by the timer selection option on the furnace control board (if applicable

Option 2

• Heat pump thermostat
• Three stage heat/single-stage or two-stage cooling
• Emergency heat function
• 2nd stage furnace is controlled by 3rd stage heat call from the thermostat. With this application, the 2nd stage timer selection option on the furnace control board must be set to the NONE position (if applicable).

NOTES

1. See thermostat installation instructions for proper emergency heat, W2, AUX, and Y2 connections.
2. WARNING : Certain oil furnaces require connections at pigtail wires, or other thermostat connection points, not at the circuit board. See furnace installation instructions for proper connection requirements. Connections at the wrong points may bypass safety controls.
3. Y-Y2 jumper on two-stage furnace board must be clipped for two-stage cooling operation. O jumper on a two-stage board must be clipped for the heat pump and two-stage variable speed combination.
4. Do not connect furnace W2 terminal to fossil fuel board if using the 2nd stage timer feature of furnace ignition control (if applicable).
5. The compressor was prevented from restarting within 3 minutes of an off-cycle or on power-up (a feature of fossil fuel board).
6. The heat pump defrost feature includes a 5-minute compressor off delay during which the compressor is prevented from restarting within 5 minutes of an off cycle.

Outdoor Thermostat Typical Wiring Connections

Emergency Heat
The emergency heat function overrides the heat pump function and the outdoor stat ODT function. The emergency heat function will energize the furnace as 1st stage heat.

Inputs (24VAC)

• R + E on T-STAT terminal strip of fossil fuel board.

Outputs (24VAC)

• W1 terminal of furnace terminal strip of fossil fuel board energizes furnace W or W1 for emergency heat call.

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