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Contactor

Contactor

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1-Pole Contactor1

 

1-Pole Contactor
2-Pole Contactor4

 

2-Pole Contactor
3-Pole Contactor29

 

3-Pole Contactor
Auxillary Contactor10

 

Auxillary Contactor

# HVAC Contactors - Air Conditioner & Heat Pump Contactors

Shop genuine OEM and premium aftermarket contactors for air conditioning systems, heat pumps, and HVAC equipment. We stock single pole, double pole, and triple pole contactors in all amp ratings from all major brands at our Westland, Michigan warehouse.

## Why Buy Contactors From Technical Hot & Cold?

**Massive Contactor Inventory**
From 20 amp to 90 amp, 1-pole to 3-pole, 24V to 240V coils - we maintain one of Michigan's largest contactor inventories for immediate availability.

**Quality You Can Trust**
Premium contactors from industry leaders: Honeywell, White-Rodgers, Packard, Mars, and Supco. No cheap imports that fail prematurely.

**Same-Day Shipping**
Real inventory in our Westland warehouse means your contactor ships today when ordered before 3PM EST.

**Expert Selection Help**
Can't find your contactor specs? Our team can help identify the correct replacement based on your equipment or old contactor information.

## What is an HVAC Contactor?

A contactor is an electrically-controlled switch that:
- Turns the air conditioner compressor on and off
- Controls power to the condenser fan motor
- Operated by 24V signal from thermostat
- Heavy-duty switch for high amperage loads
- Safety component with thermal overload protection

**Located:** Inside the outdoor condenser unit
**Function:** Main power switch for AC compressor and fan

## Types of Contactors

### Single-Pole Contactors (1-Pole)
One set of contacts for switching one hot leg.

**Applications:**
- Single-phase compressors (residential)
- 120V or 240V loads
- Single component control
- Less common in residential AC

**Amp Ratings:** 20A, 25A, 30A, 40A

### Double-Pole Contactors (2-Pole) 
Two sets of contacts - most common in residential AC.

**Applications:**
- Single-phase air conditioners
- 208V or 230V compressors
- Switches both hot legs
- Standard residential AC systems

**Amp Ratings:** 20A, 25A, 30A, 35A, 40A, 45A, 50A, 60A, 75A, 90A

### Triple-Pole Contactors (3-Pole)
Three sets of contacts for three-phase power.

**Applications:**
- Commercial air conditioning
- Three-phase compressors
- Industrial HVAC equipment
- 208V, 230V, or 480V systems

**Amp Ratings:** 30A, 40A, 50A, 60A, 75A, 90A

### Definite Purpose Contactors
Heavy-duty contactors specifically designed for HVAC applications.

**Features:**
- Silver contacts (better than bronze)
- Rated for 100,000+ operations
- Built-in thermal overload protection
- Resistive or inductive load ratings
- UL/CSA listed for HVAC use

## Contactor Specifications

### Critical Specifications to Match:

1. **Poles** - 1-pole, 2-pole, or 3-pole
2. **Amp Rating** - Must be equal or greater than old contactor
3. **Voltage** - 24V, 120V, 208V, 230V, or 480V
4. **Coil Voltage** - Usually 24V for residential
5. **Contact Material** - Silver (preferred) or bronze

### Important Specifications:

6. **Mounting** - Box mount or DIN rail
7. **Terminal Type** - Screw, push-in, or blade
8. **Physical Size** - Ensure fit in existing space
9. **Load Type Rating** - Resistive or inductive

## Popular Contactor Brands

**Premium Brands:**
- **Honeywell** - Industry-leading contactors
- **White-Rodgers** - Heavy-duty HVAC contactors
- **Packard** - Quality definite purpose contactors
- **Mars** - Reliable contactors for all applications
- **Supco** - Professional-grade HVAC contactors
- **Furnas/Siemens** - Industrial-strength contactors

**OEM Brands:**
- **Carrier** - OEM contactors for Carrier equipment
- **Trane** - OEM contactors for Trane systems
- **Lennox** - OEM contactors for Lennox units
- **Goodman** - OEM contactors for Goodman AC

## How to Size a Contactor

### Determine Required Amp Rating:

**Method 1 - Use Old Contactor:**
- Match the amp rating on old contactor
- Can go higher, never lower
- Most common: 30A, 40A, 50A

**Method 2 - Calculate From Equipment:**
- Find compressor RLA (Rated Load Amps) on data plate
- Find fan motor FLA (Full Load Amps) on motor
- Add together
- Multiply by 1.25 for safety factor
- Round up to next standard size

**Example:**
- Compressor RLA: 18 amps
- Fan motor FLA: 2 amps
- Total: 20 amps
- With safety factor: 20 x 1.25 = 25 amps
- **Use 30 amp contactor** (next size up)

### Amp Rating Selection Chart:

**Residential AC Systems:**
- **1.5-2 ton:** 20A or 25A contactor
- **2-3 ton:** 30A contactor
- **3-4 ton:** 35A or 40A contactor
- **4-5 ton:** 45A or 50A contactor
- **5-6 ton:** 60A contactor

**Commercial Systems:**
- **Calculate based on total load**
- **Add all connected devices**
- **Apply 1.25 safety factor**

## Contactor Troubleshooting

### Signs of Bad Contactor:

**Won't Close (Pull In):**
- No click when thermostat calls
- 24V present at coil, no operation
- Visible pitting on coil
- Burned coil winding

**Chatters:**
- Rapid clicking sound
- Contacts open and close repeatedly
- Low voltage to coil
- Weak coil or stuck armature

**Welded Contacts:**
- AC runs continuously
- Can't turn off at thermostat
- Contacts stuck closed
- Manual opening difficult

**Burned Contacts:**
- Blackened or pitted contact surfaces
- Arcing visible
- Intermittent operation
- High resistance causing heat

**Coil Failure:**
- No magnetism when energized
- Coil gets very hot
- Burned smell
- Visual damage

### Diagnostic Steps:

1. **Verify 24V at Coil**
   - Use multimeter
   - Should read 24V when calling for cooling
   - No voltage = thermostat/wire problem

2. **Check for Pull-In**
   - Should hear distinct click
   - Manual test: push in (power off!)
   - Stuck = mechanical problem

3. **Inspect Contacts**
   - Look for pitting, burning
   - Should be smooth and clean
   - Severe pitting = replacement needed

4. **Test Operation**
   - Monitor during several cycles
   - Should close/open cleanly
   - Chattering = problem

5. **Check Connections**
   - All terminals tight
   - No loose or corroded connections
   - Proper wire size

## Contactor Installation

**Safety Critical:**
1. Turn off all power (disconnect and breaker)
2. Verify no voltage with tester
3. Discharge capacitors before touching wires
4. Take photos of all connections

**Replacement Steps:**

1. **Document Connections**
   - Photo every wire
   - Label if needed
   - Note wire colors and positions

2. **Disconnect Wires**
   - Start with line side (top)
   - Then load side (bottom)
   - Finally coil wires

3. **Remove Old Contactor**
   - Usually 2 mounting screws
   - May need to remove mounting plate

4. **Install New Contactor**
   - Position in same location
   - Secure mounting screws
   - Ensure proper clearances

5. **Reconnect Wires**
   - Match exactly to photos
   - Line (power) to top terminals
   - Load (compressor/fan) to bottom
   - 24V coil wires (polarity doesn't matter)

6. **Double-Check Everything**
   - All connections tight
   - No loose wires
   - Proper spacing between terminals
   - Cover/shroud in place

7. **Test Operation**
   - Restore power
   - Call for cooling
   - Listen for clean click
   - Monitor for several cycles

## Common Installation Mistakes

❌ **Reversed Line and Load**
- Dangerous - can cause equipment damage
- Line (power) ALWAYS goes to top
- Load (equipment) ALWAYS goes to bottom

❌ **Wrong Amp Rating**
- Too small = overheating and failure
- Never downsize amp rating
- Can upsize if necessary

❌ **Loose Connections**
- Causes arcing and overheating
- Tighten all terminals securely
- Check periodically

❌ **Crossing Phases**
- On 2-pole contactors, keep phases separate
- L1 and L2 shouldn't cross
- Follow wiring diagram

## Contactor Maintenance

**Annual Service:**
- Inspect contacts for pitting
- Check all connections
- Verify smooth operation
- Clean any debris
- Test pull-in voltage

**When to Replace:**
- Pitted or burned contacts
- Chattering operation
- Stuck or slow operation
- Overheating
- 10+ years old (preventive)

**Preventive Replacement:**
Many contractors replace contactors during:
- Compressor replacement
- Major repairs
- System over 10 years old
- After lightning strikes

## Contactor FAQs

**Q: Why did my contactor fail?**
A: Common causes:
- Normal wear (electrical arcing)
- Undersized for load
- Voltage issues (low or high)
- Lightning strikes
- Compressor problems causing high current
- Poor connections causing heat

**Q: Can I use a higher amp contactor?**
A: Yes! You can use a higher amp rating (30A instead of 25A). Never use lower. Higher rating provides extra capacity and may last longer.

**Q: Does coil voltage matter?**
A: Yes! Must match your control voltage. Most residential is 24V. Using wrong coil voltage = won't work or failure.

**Q: Can I clean contacts instead of replacing?**
A: Not recommended. Pitted contacts indicate metal transfer. Cleaning temporarily helps but contactor will fail soon. Replace for reliability.

**Q: Why does my contactor chatter?**
A: Causes:
- Low voltage (weak transformer)
- Poor connections
- Weak coil
- Debris/dirt in mechanism

**Q: Can I replace just the contacts?**
A: Theoretically yes, but replacement contacts are expensive and labor-intensive. New contactor is usually more cost-effective.

**Q: What causes welded contacts?**
A: High inrush current, such as:
- Compressor short cycling
- Low voltage
- Undersized contactor
- Bad capacitor
- Compressor problems

**Q: Should I replace anything else with the contactor?**
A: Recommended:
- Disconnect switch if corroded
- Capacitors (good preventive maintenance)
- Clean condenser coil while you're there

## Contactor Accessories

**Hard Start Kits:**
- Reduces inrush current
- Protects contactors
- Extends contactor life

**Time Delay Relays:**
- Prevents rapid cycling
- Compressor protection
- Required for some applications

**Coil Savers:**
- Surge protection for coil
- Extends coil life
- Inexpensive insurance

## Need Help Selecting a Contactor?

Our HVAC parts specialists are here to help! Contact us:
- **Phone:** [Your phone number]
- **Email:** [Your email]
- **Hours:** [Your business hours]
- **Location:** Westland, MI - Local pickup available

**Have your equipment model number or old contactor specifications ready. Browse our contactor selection below or contact us for expert assistance!**

Can't find what you're looking for?

If you don't see your model or part, call us! Our friendly technicians are standing by. We can help you find the part you need with guaranteed fitment. Speak with us today at (734) 326-3900.

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