⚙️ Harvia LTY17 Power Extension Unit – Expand Your Sauna Control to 37kW

Unlock commercial-grade sauna heater capacity with Finnish engineering precision

♨️ Product Overview

The Harvia LTY17 Power Extension Unit is an essential control system component designed to expand the output range of Harvia control units, enabling the operation of high-powered 2-group electric sauna heaters in commercial and large public saunas. Manufactured by Harvia, the world’s leading sauna and spa company headquartered in Finland, this power extension unit represents the pinnacle of reliable sauna control technology.

By integrating the LTY17 with compatible Harvia control units, installers can extend heater control capacity up to an impressive 37kW, making it the ideal solution for spa facilities, hotels, wellness centres, and large private installations where standard control units simply cannot handle the power requirements.

The LTY17 is engineered for professional applications where reliability and safety are paramount. With IPX2 protection rating and robust wall-mountable construction, it delivers dependable performance in demanding commercial environments whilst maintaining full compatibility with Harvia’s acclaimed Xenio, Griffin, Xafir, and C-series control systems.

⭐ Key Features

✅ Maximum Load Capacity 20kW – Handles substantial power output to extend system capability up to 37kW when paired with compatible control units

✅ 400V 3-Phase Supply – Designed for commercial three-phase electrical installations (400V 3N~), ensuring robust power handling for large heaters

✅ IPX2 Protection Rating – Splash-proof construction suitable for installation in technical areas adjacent to sauna rooms

✅ Universal Harvia Compatibility – Works seamlessly with Xenio (CX110, CX170), Griffin (CG170), Xafir (CS110, CS170), and C-series (C90, C105S) control units

✅ Compact Wall-Mounted Design – Space-efficient dimensions (281 × 70 × 224mm) allow installation in confined plant rooms

✅ Parallel Heater Control – Supports parallel drive configuration for controlling two physically separate heaters from a single control system

✅ Lightweight Construction – At just 1.9kg, installation is straightforward and mounting requirements are minimal

✅ Finnish Engineering Quality – Manufactured by Harvia with rigorous quality control standards for commercial durability

✅ Combi Heater Support – Compatible with Combi heater configurations incorporating steam generators (with LTY17 variant)

✅ Comprehensive Wiring Diagrams – Detailed installation manual includes clear electrical schematics for all compatible control unit combinations

🔧 Technical Specifications

Specification	Value
Model	LTY17
Part Number	SHCONLTY170400
Supply Voltage	400V 3N~ (Three-phase)
Maximum Load	20 kW
Extended System Capacity	Up to 37 kW (with compatible control unit)
Protection Class	IPX2
Mounting Type	Wall mounted
Dimensions (W × D × H)	281 × 70 × 224 mm
Weight	1.9 kg
Installation Location	Dry area, outside sauna room
Operating Temperature	Above 0°C ambient
Manufacturer	Harvia (Finland)

📐 System Capacity Guide

The Harvia LTY17 extends the control capacity of Harvia control units, enabling operation of larger commercial heaters.

Maximum System Capacities with LTY17:

Control Unit Combination	Maximum Heater Power
CX170/CS170 + LTY17	Up to 37 kW
CG170 + LTY17	Up to 37 kW
CX110/CS110 + LTY17	Up to 31 kW
C90 + LTY17	Up to 29 kW
CG170C/CX110C/CS110C + LTY17	Up to 31 kW (Combi)
C105S + LTY17	Up to 30.5 kW (Combi)

Heater Group Configuration:

The LTY17 is designed for 2-group connected heaters commonly used in large commercial saunas. In this configuration, the heater elements are divided into two separate electrical groups, each requiring independent control circuits.

💷 Investment Considerations

The Harvia LTY17 Power Extension Unit is a control system component rather than a standalone energy-consuming device. Your running costs will be determined by the sauna heater connected to the system.

Example: Large Commercial Sauna Operating Costs

Using current Ofgem electricity rates (£0.263/kWh, Q4 2025):

Heater Size	Session (1.5 hrs)	Weekly (5 sessions)	Annual Cost
20 kW	£7.89	£39.45	£2,052
30 kW	£11.84	£59.18	£3,078
37 kW	£14.60	£73.01	£3,797

Based on heater operating at average 75% duty cycle. Actual costs depend on sauna size, insulation, usage patterns and current energy rates.

⚡ Installation Requirements

Electrical Requirements

Requirement	Specification
Supply Voltage	400V 3N~ (Three-phase + Neutral)
Circuit Type	Dedicated circuit required
Installation Standard	BS 7671 (IET Wiring Regulations)

Cable and Fuse Sizing (by connected heater power):

Heater Power	Cable A (min.)	Cable B H07RN-F (min.)	Fuse Rating
0 – 6.9 kW	5 × 1.5 mm²	5 × 1.5 mm²	10 A
7 – 11 kW	5 × 2.5 mm²	5 × 1.5 mm²	16 A
11.1 – 17 kW	5 × 6 mm²	5 × 2.5 mm²	25 A
17.1 – 20 kW	5 × 10 mm²	5 × 6 mm²	32 A

Installation Location

Requirement	Specification
Location	Dry area, outside sauna room
Proximity	Near control unit power unit
Ambient Temperature	Above 0°C
Mounting	Wall surface mounted only

⚠️ CRITICAL: Do NOT embed the power extension unit into wall structures. Recessed installation prevents adequate ventilation and will cause overheating of internal components, leading to equipment damage and potential safety hazards.

⚠️ IMPORTANT: All electrical connections must be carried out by a qualified 
electrician in accordance with BS 7671 (IET Wiring Regulations), local 
building codes, and manufacturer specifications. Incorrect installation 
may result in equipment damage, fire risk, or electric shock.

🛡️ Safety Features & Certifications

Built-in Protection:

✅ IPX2 splash protection rating for installation near sauna facilities

✅ Designed for operation with Harvia control units incorporating thermal cut-out protection

✅ Overload protection via properly sized circuit breakers and fuses

✅ Requires proper earthing/grounding as per BS 7671 requirements

System Safety (via compatible control units):

✅ Automatic heater shutdown via control unit timer

✅ Temperature regulation via control unit thermostat

✅ Safety sensor monitoring for heater overheat protection

Certifications:

✅ CE Marked

✅ Designed and manufactured by Harvia Oy, Finland

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🎯 Ideal Applications

Application	Use Case	Typical Configuration
🏨 Hotels & Resorts	Large guest saunas with extended operating hours	20-30 kW heaters with CG170+LTY17
🧖 Spa & Wellness Centres	High-capacity commercial saunas serving multiple clients	25-37 kW heaters with CX170+LTY17
🏋️ Fitness Clubs & Gyms	Heavy-use saunas with demanding heating requirements	20-25 kW heaters with CX110+LTY17
🏢 Corporate Facilities	Executive wellness suites and employee amenities	17-25 kW heaters with C90+LTY17
🏠 Large Private Residences	Substantial home saunas exceeding standard control capacity	17-20 kW heaters with CS110+LTY17
🏊 Swimming Pool Complexes	High-throughput saunas adjacent to aquatic facilities	25-37 kW heaters with CG170+LTY17

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🎛️ Compatible Control Units & Accessories

Compatible Harvia Control Units

For Standard Heaters:

• Harvia Xenio CX170 / CX110
• Harvia Xafir CS170 / CS110
• Harvia Griffin CG170
• Harvia C90

For Combi Heaters (with single steam generator):

• Harvia Xenio Combi CX110C
• Harvia Xafir Combi CS110C
• Harvia Griffin Combi CG170C
• Harvia C105S

Parallel Drive Configuration

The LTY17 enables parallel drive operation, allowing a single control system to manage two physically separate heaters. This configuration requires:

• Primary temperature sensor WX232 (installed above higher-power heater)
• Parallel drive sensor WX314 (optional accessory, installed above second heater)

Note: For Hidden Heater (HH) models with parallel drive, contact Harvia directly for specific configuration guidance.

Related Product: LTY17C

For installations requiring two steam generators or dual Combi heater configurations, the Harvia LTY17C variant is available with maximum load capacity of 17kW and additional steam control connections.

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❓ Frequently Asked Questions

Q: Can I use the LTY17 without a Harvia control unit? A: No. The LTY17 is a power extension unit designed to work exclusively with compatible Harvia control units (Xenio, Xafir, Griffin, C90, C105S series). It cannot operate independently and must always be connected to a primary control unit.

Q: What is the maximum heater size I can control with the LTY17? A: With the LTY17, the maximum system capacity reaches 37kW when paired with CX170, CS170, or CG170 control units. The LTY17 itself handles up to 20kW, with the remaining capacity managed by the primary control unit.

Q: What electrical supply do I need? A: The LTY17 requires a 400V three-phase supply with neutral (400V 3N~). This is standard commercial three-phase power in the UK. A qualified electrician must install dedicated circuits with appropriate cable sizing and circuit protection.

Q: Can I control two separate heaters with one control system? A: Yes. The LTY17 supports parallel drive configuration, enabling control of two physically separate heaters from a single Harvia control system. This requires the optional parallel drive sensor WX314 for the secondary heater’s overheat protection.

Q: Where should the LTY17 be installed? A: Install the LTY17 in a dry location outside the sauna room, near the main control unit power unit. The ambient temperature must remain above 0°C. Surface wall mounting is required; never embed the unit into wall cavities.

Q: Is the LTY17 suitable for domestic installations? A: The LTY17 is designed primarily for commercial applications due to the three-phase power requirement. Most domestic UK properties have single-phase supplies. However, if your property has three-phase power and requires heater control above 17kW, the LTY17 may be appropriate.

Q: What is the difference between LTY17 and LTY17C? A: The LTY17 is designed for standard heaters and Combi heaters with a single steam generator. The LTY17C is specifically designed for configurations with two steam generators or dual Combi heater setups, with a maximum load of 17kW and additional steam control connections.

📥 Downloads & Resources

📄 Installation Manual (PDF) – Complete installation guide with wiring diagrams for all compatible control unit combinations

🏆 Why Choose the Harvia LTY17

✅ Industry-Leading Manufacturer – Harvia is the world’s largest sauna and spa company, renowned for quality and reliability

✅ Proven Commercial Performance – Engineered for demanding commercial environments with high-throughput requirements

✅ Comprehensive Compatibility – Works with the full range of Harvia’s professional control unit series

✅ Flexible Configuration – Supports both 2-group heaters and parallel dual-heater installations

✅ Future-Proof Investment – Extend existing control systems rather than replacing entire installations

✅ Professional Documentation – Detailed wiring diagrams and installation instructions for confident professional installation

🤝 Why Buy from Parts4Tubs

✅ UK-Based Company – Local support and expertise from our Northamptonshire headquarters

✅ Sauna Specialists – Expert knowledge of Harvia products and commercial sauna installations

✅ Competitive Pricing – £327.60 inc. VAT with no hidden charges

✅ Technical Support – Assistance with product selection and compatibility queries

✅ Fast UK Delivery – Prompt dispatch to get your project moving

✅ Full Warranty Support – Manufacturer warranty backed by Parts4Tubs service

✨ Summary

The Harvia LTY17 Power Extension Unit is the essential control system upgrade for commercial sauna installations requiring heater capacity beyond standard control unit limits. Extending system capacity up to 37kW, this Finnish-engineered component delivers the reliability and performance demanded by hotels, spas, wellness centres, and fitness facilities. With IPX2 protection, comprehensive Harvia control unit compatibility, and support for parallel heater configurations, the LTY17 provides a cost-effective solution for expanding existing installations or specifying new high-capacity systems. Backed by Harvia’s global reputation and Parts4Tubs UK expertise, invest with confidence in proven sauna technology.