🔧 Harvia Power Extension Unit LTY45 – Expand Your Sauna Control System to 38kW

Unlock higher power capacity for large-scale sauna installations with professional-grade relay technology

♨️ Product Overview

The Harvia Power Extension Unit LTY45 is an essential component for controlling high-powered electric sauna heaters in large commercial and residential sauna installations. Manufactured by Harvia, Finland’s leading sauna company with over 75 years of expertise, this professional-grade power extension module enables seamless control of 2-group electric heaters that exceed standard control unit capacity.

When paired with compatible Harvia Xenio control units, the LTY45 expands maximum load capacity up to an impressive 38kW, making it ideal for spa facilities, wellness centres, hotels, and large custom sauna builds. The unit features robust stainless steel construction, wall-mountable design, and comprehensive safety protections that meet professional installation standards.

Designed exclusively for use with Harvia control systems, this power extension unit cannot operate independently—it works in harmony with your existing Xenio CX30, CX45, or CX170 control panel to deliver precise, reliable heater management for demanding applications.

✨ Key Features

✅ Expanded Power Capacity – Increases maximum controllable load up to 38kW when combined with compatible Harvia control units, enabling control of the most powerful commercial heaters

✅ Professional-Grade 45A Contactors – Heavy-duty relay components designed for continuous commercial sauna operation with excellent thermal management

✅ Stainless Steel Construction – Durable corrosion-resistant metal enclosure built to withstand the demanding environment of sauna installations

✅ IPX2 Protection Rating – Protected against dripping water at 15° from vertical, suitable for installation in dry areas adjacent to sauna rooms

✅ Wall-Mountable Design – Compact form factor with included mounting hardware for easy professional installation outside the sauna room

✅ Multi-Heater Control – Enables single control panel management of two separate heater circuits for complex sauna configurations

✅ Comprehensive Safety Features – Built-in overload protection, emergency shutdown capability, and circuit isolation for safe operation

✅ Wide Operating Temperature Range – Functions reliably from -10°C to +40°C ambient temperature

✅ Universal Compatibility – Works with Harvia Xenio CX30, CX45, and CX170 control unit series

✅ ETL Certified – Third-party safety certification for electrical products ensuring compliance with North American safety standards

⚙️ Technical Specifications

Specification	Value
Model Number	LTY45-U1-U3
Product Type	Power Extension Module
Supply Voltage	240V 1Ph / 208V 3Ph (60Hz)
Maximum Load (LTY45-U1, 240V)	21 kW per circuit / 10.5 kW single wire
Maximum Load (LTY45-U3, 208V)	15.6 kW
Maximum System Capacity	Up to 38 kW (with compatible control unit)
Contactor Rating	45A per cable
Dimensions (H × W × D)	364 mm × 267 mm × 73 mm
Net Weight	2.1 kg
Gross Weight (Packaged)	2.5 kg
Package Dimensions	300 mm × 225 mm × 135 mm
Construction Material	Stainless Steel Enclosure
Protection Class	IPX2
Operating Temperature	-10°C to +40°C
Installation Type	Wall-mounted (exterior to sauna room)
Control Circuit Wiring	AWG 18
Certifications	ETL Listed
Warranty	1 Year Manufacturer Warranty

📐 System Configuration Guide

The Harvia Power Extension Unit LTY45 is designed to expand the capabilities of your existing Harvia control system. Understanding the correct configuration is essential for optimal performance.

Maximum Load Configurations

With CX30 Control Unit:

• Circuit A: Up to 15.6 kW (208V 3Ph) or 10.5-21 kW (240V 1Ph depending on wiring configuration)
• Circuit B: Up to 10.5-10.8 kW

With CX45 Control Unit:

• Circuit A: Up to 15.6 kW (208V 3Ph) or 10.5-21 kW (240V 1Ph)
• Circuit B: Up to 15-17 kW

Wiring Configuration Impact

The maximum achievable load depends on your wiring configuration between the power extension unit and the heater:

📍 Example Configuration (240V 1Ph with CX45):

• Two supply wires: Maximum 10.5 kW per circuit
• Four supply wires: Maximum 21 kW on Circuit A, 17 kW on Circuit B
• Total system capacity: Up to 38 kW combined

⚠️ Wire sizing must match the power being carried. Consult the installation manual for specific AWG requirements based on your load.

💷 Energy Considerations

While the Power Extension Unit itself does not consume significant energy (it simply controls heater operation), understanding the running costs of high-powered sauna systems is important for planning purposes.

UK Electricity Rate Used: £0.2635/kWh (Ofgem Price Cap, Q4 2025)

Indicative Heater Running Costs (for systems using this extension unit)

Heater Power	1 Hour Session	3 Sessions/Week (Annual)	6 Sessions/Week (Annual)
15 kW	£3.95	£617	£1,234
20 kW	£5.27	£822	£1,644
30 kW	£7.91	£1,234	£2,468
38 kW	£10.01	£1,562	£3,124

Example Calculation (20 kW system):

Per Session: 20 kW × 1 hour × £0.2635 = £5.27
Annual (3x weekly): £5.27 × 3 × 52 = £822

⚠️ Actual costs depend on your heater size, session duration, room insulation, and current energy tariffs. Commercial installations should factor in three-phase electricity tariffs which may differ from domestic rates.

⚡ Installation Requirements

Electrical Specifications

Requirement	Specification
Supply Voltage Options	240V 1Ph (60Hz) or 208V 3Ph (60Hz)
Maximum Current per Cable	45A (LTY45 unit)
Control Circuit Wiring	AWG 18 minimum
Main Power Wiring	AWG 6-14 depending on load (see manual)
Dedicated Circuit	Required
Sub-Panel Requirement	2-pole or 3-pole breaker subpanel (for grouped heaters)

Cable Sizing Guide (240V 1Ph)

Power Per Circuit	Minimum Cable Size (AWG)
0 – 4.3 kW	14
4.4 – 6.0 kW	12
6.1 – 7.2 kW	10
7.3 – 9.6 kW	8
9.7 – 10.5 kW	6

Installation Location Requirements

• Mount outside the sauna room in a dry location
• Ambient temperature must remain between -10°C and +40°C
• Do not embed the unit into walls (may cause overheating)
• Install in vicinity of the main control unit for optimal wiring routing
• Ensure adequate ventilation around the unit

⚠️ IMPORTANT: All electrical connections must be carried out by a qualified electrician 
in accordance with local electrical codes and regulations. In the UK, installation should 
comply with BS 7671 (IET Wiring Regulations) and Part P of the Building Regulations.

🛡️ Safety Features & Certifications

Built-in Safety Systems

✅ Overload Protection – Prevents damage from excessive current draw

✅ Circuit Isolation – Separate circuits ensure independent safety shutdown capability

✅ Professional Terminal Design – Secure wire connections with torque specification (1.8 Nm / 1.3 ft-lb)

✅ Overheat Protection Integration – Works with heater safety devices for comprehensive protection

✅ Emergency Shutdown Capability – System can be shut down via main control unit in emergency situations

Certifications

✅ ETL Listed – Certified for electrical safety by Intertek

✅ IPX2 Rated – Protection against dripping water

🎯 Ideal Applications

Application	Power Range	Typical Setup
🏢 Large Commercial Saunas	20-38 kW	Hotels, spas, wellness centres requiring high-capacity heating
🧖 Multi-Heater Installations	15-30 kW	Single control of two separate sauna heaters
🏋️ Gym & Fitness Facilities	15-25 kW	High-throughput sauna rooms with quick recovery needs
🏨 Hotel Wellness Suites	18-35 kW	Premium installations with powerful heating requirements
🪵 Large Custom Saunas	20-38 kW	Bespoke installations exceeding standard control unit capacity
⚡ Power Upgrade Projects	Variable	Upgrading existing installations to higher-powered heaters

🎛️ Control System Compatibility

Compatible Control Units

The Harvia Power Extension Unit LTY45 is designed to work with the following Harvia control systems:

Control Unit	Maximum Output	Combined Capacity with LTY45
Xenio CX30	17 kW	Up to 30+ kW
Xenio CX45	17 kW	Up to 38 kW
Xenio CX170	17 kW	Up to 34 kW

Combi Heater Support

For installations featuring combination sauna heater/steamer units, the LTY45C variant is available, supporting:

• Heater control up to 18.9 kW
• Integrated steamer control (2.1 kW additional)
• Total capacity up to 33.7 kW for combi systems

❓ Frequently Asked Questions

Q: Can the power extension unit operate without a control unit? A: No, the LTY45 is designed exclusively to work with compatible Harvia control units (CX30, CX45, CX170). It cannot control heaters independently.

Q: What is the maximum heater power this unit can control? A: When combined with a compatible control unit, the system can manage heaters up to 38kW total capacity. Individual circuit limits vary based on wiring configuration and control unit model.

Q: Where should the power extension unit be installed? A: Install outside the sauna room in a dry area with ambient temperatures between -10°C and +40°C. Wall mounting is standard; do not embed in walls.

Q: What electrical supply is required? A: The unit accepts 240V single-phase or 208V three-phase supply at 60Hz. Maximum current rating is 45A per cable. Professional installation by a qualified electrician is mandatory.

Q: Is this suitable for UK installation? A: This model (LTY45-U1-U3) is designed for North American electrical systems (60Hz). For UK and European installations operating at 50Hz and 400V 3-phase, the LTY17 model may be more appropriate. Please contact Parts4Tubs for guidance on your specific installation requirements.

Q: What warranty is provided? A: Harvia provides a 1-year manufacturer warranty covering defects in materials and workmanship. The warranty requires professional installation by a licensed electrician.

Q: Can I control multiple heaters with one control panel? A: Yes, the power extension unit enables control of two separate heater circuits from a single Harvia control panel, making it ideal for large or multi-zone sauna installations.

📥 Downloads & Resources

📄 Installation & User Manual (PDF) – Complete installation guide with wiring diagrams

🏆 Why Choose the Harvia LTY45 Power Extension Unit

✅ Finnish Engineering Excellence – Harvia has been the world leader in sauna technology for over 75 years, trusted by professionals worldwide

✅ Expand Without Replacing – Add capacity to your existing Xenio control system without costly complete replacement

✅ Commercial-Grade Reliability – 45A contactors and robust construction designed for demanding continuous operation

✅ Flexible Configuration – Multiple wiring options allow optimisation for your specific installation requirements

✅ Comprehensive Safety – ETL certification and integrated protection systems ensure safe operation

✅ Professional Support – Detailed documentation and wiring diagrams simplify professional installation

🤝 Why Buy from Parts4Tubs

✅ UK-based company with local customer support and expertise

✅ Fast UK delivery on all orders

✅ Expert advice from sauna and spa specialists who understand your requirements

✅ Competitive pricing on genuine Harvia products

✅ Full warranty support for all products sold

✅ Easy returns within 30 days if you change your mind

✨ Summary

The Harvia Power Extension Unit LTY45 delivers professional-grade power expansion for demanding sauna installations requiring control capacity beyond standard Xenio units. With its 38kW maximum combined capacity, ETL certification, and robust stainless steel construction, it’s the trusted choice for commercial spas, wellness centres, and large custom saunas. Backed by Harvia’s 75 years of Finnish sauna expertise and Parts4Tubs’ UK-based support, you can expand your sauna control system with confidence. Contact us today for expert guidance on your installation requirements.