1″ Male ASHP Antifreeze Valve
Automatic Heat Pump Frost Protection
Water-filled pipework around an outdoor heat pump can become vulnerable during freezing weather.
The risk becomes greater if circulation stops because of a power cut, system fault or prolonged shutdown.
This mechanical antifreeze valve responds automatically to falling water temperature.
Therefore, it provides passive frost protection without relying on electricity or external controls.
1″ Male BSP Connections
This version uses 1″ male threaded connections.
Therefore, it suits compatible threaded heat pump pipework, unions and hydraulic components.
The ZL-7201 range includes 1″ male, larger male threaded and 28mm compression versions.
Always check the adjoining connection type before ordering.
Designed for Air Source Heat Pumps
The valve suits compatible water-based heat pump installations.
Typical applications include:
- Air source heat pumps
- Monobloc heat pumps
- 1″ threaded ASHP pipework
- Heat pump flow pipework
- Heat pump return pipework
- External heat pump pipework
- Heat pump replacement work
- New ASHP installations
- Renewable heating systems
- Heat pump servicing
Always follow the heat pump manufacturer’s frost-protection requirements.
Opens Automatically at 3°C
The valve monitors the temperature of the system water passing through it.
When the water temperature falls to approximately 3°C, the antifreeze mechanism opens.
Water then discharges from the exposed circuit.
This helps reduce the risk of ice forming inside the heat pump and external pipework.
Automatically Closes at 4°C
Once the water temperature rises to approximately 4°C, the valve closes again.
Therefore, the system does not require manual resetting after normal operation.
The published operating accuracy is approximately ±1°C.
No Electrical Supply Required
The antifreeze valve operates mechanically.
As a result, it does not need:
- Mains electricity
- Batteries
- A thermostat
- A control cable
- Wi-Fi
- External sensors
This is especially useful during power failures, when normal heat pump frost-protection controls may not operate.
Suitable for Water-Based Systems
The ZL-7201 antifreeze valve is designed for water-based heating circuits.
If the heating system contains glycol or another heat-transfer fluid, check the heat pump manufacturer’s requirements before installing an antifreeze valve.
Do not assume that every heat pump requires the same frost-protection method.
10 Bar Maximum Working Pressure
The published maximum working pressure is 10 bar.
Therefore, the valve covers the operating pressures found in many domestic and light-commercial heat pump installations.
Always confirm the complete system design before installation.
0°C to 65°C Working Temperature
The valve has a published water working range of 0°C to 65°C.
Its ambient operating range is -30°C to 60°C.
This makes the valve suitable for exposed heat pump pipework where freezing conditions may occur.
High-Flow 1″ Design
The 1″ ZL-7201 version has a published Kv value of 55m³/h.
Therefore, the valve provides a large flow path for compatible heat pump primary circuits.
However, always size the complete hydraulic system according to the heat pump manufacturer’s requirements.
Brass Construction
The ZL-7201 family uses a robust brass valve body.
Published material data identifies CW617N brass, stainless steel internal springs and EPDM seals.
This construction suits professional heating and heat pump installations.
Ideal for Monobloc Heat Pumps
A monobloc heat pump contains water connections at the outdoor unit.
Therefore, sections of the primary circuit can remain outdoors.
If power or circulation fails during freezing weather, exposed water can freeze.
An antifreeze valve provides an additional mechanical layer of protection where the heat pump manufacturer permits this method.
Install on Flow and Return Where Required
Heat pump frost-protection arrangements commonly place antifreeze protection on the exposed flow and return pipework.
This helps protect both sides of the external hydraulic circuit.
However, the number, position and orientation of valves must follow the heat pump manufacturer’s installation instructions.
Correct Installation Position Matters
Install the valve in the correct orientation so discharged water can leave freely.
The antifreeze discharge outlet must not become obstructed.
In addition, avoid any installation arrangement where discharged water could create a safety hazard or damage surrounding equipment.
Always follow the manufacturer’s current installation instructions.
Do Not Block the Discharge Outlet
The antifreeze valve protects the system by releasing water.
Therefore, the outlet must remain free to discharge.
Do not cap, isolate or obstruct the discharge point.
Also consider where discharged water may freeze once it reaches the ground.
Useful During Power Cuts
Modern heat pumps normally include electronic frost-protection functions.
However, those controls may depend on electrical power and pump circulation.
A mechanical antifreeze valve provides another form of protection because its operation does not rely on electricity.
This can prove particularly valuable during prolonged winter power failures.
Antifreeze Valve or Glycol?
Some heat pump installations use mechanical antifreeze valves.
Others use a water/glycol mixture.
The correct approach depends on:
- Heat pump manufacturer
- System design
- Location
- Outdoor pipework
- Water treatment
- Required frost protection
- Installer specification
Therefore, never substitute one frost-protection strategy for another without checking the heat pump manufacturer’s requirements.
1″ Male vs 28mm Compression
Kudos Trading now offers different connection options within the antifreeze valve range.
Choose the 1″ male version where the installation uses compatible threaded connections.
Alternatively, choose the 28mm ASHP Antifreeze Valve where the external pipework uses a 28mm compression connection.
This gives installers greater flexibility when matching the valve to the heat pump pipework.
Ideal for Heat Pump Replacement Work
Antifreeze valves may need replacing during the life of the system.
Common reasons include:
- Valve damage
- Frost-related damage
- Leakage
- System alterations
- Heat pump replacement
- Pipework changes
- Existing valve failure
- ASHP servicing
- Installation upgrades
The ZL-7201-1M provides a useful replacement option where the original installation uses compatible 1″ male connections.
Technical Specifications
| Specification | Details |
|---|---|
| Brand | Kudos Trading |
| Product | ASHP Antifreeze Valve |
| Product Code | ZL-7201-1M |
| Connection Size | 1″ |
| Connection Type | Male Thread / BSP |
| Medium | Water |
| Body Material | Brass CW617N |
| Internal Springs | Stainless Steel |
| Seals | EPDM |
| Maximum Working Pressure | 10 Bar |
| Working Temperature Range | 0°C to 65°C |
| Ambient Temperature Range | -30°C to 60°C |
| Opening Temperature | 3°C |
| Closing Temperature | 4°C |
| Accuracy | ±1°C |
| Antifreeze Function Enabled | Below approx. 5°C ambient |
| Kv Value | 55m³/h |
| Electrical Supply | Not Required |
| Application | Air Source Heat Pumps / Water-Based Heating |
Published ZL-7201 technical data confirms the operating temperatures, pressure rating, 1″ connection option and Kv performance.
Why Choose the 1″ Male ASHP Antifreeze Valve?
Key benefits include:
- Automatic frost protection
- Opens at approximately 3°C
- Closes at approximately 4°C
- No electricity required
- No batteries required
- 1″ male threaded connections
- 10 bar maximum working pressure
- Brass body
- EPDM seals
- High-flow design
- Suitable for compatible monobloc ASHP systems
- Useful for new installations
- Ideal for heat pump replacement work
- Designed for exposed external heating pipework
Why Buy From Kudos Trading?
Kudos Trading supplies professional heat pump, plumbing and heating products throughout the UK.
Our growing air source heat pump range includes antifreeze valves, flexible hoses, flow setters, fill and flush valves, filters and air separators.
Therefore, installers can source more of the components required for ASHP installation, servicing and replacement from one UK supplier.
We have supplied underfloor heating products to the UK since 2001.
Frequently Asked Questions
What Does a Heat Pump Antifreeze Valve Do?
It automatically releases system water when the water temperature approaches freezing.
This helps prevent ice from forming inside exposed heat pump pipework and components.
What Connection Does This Valve Have?
This version uses 1″ male threaded connections.
Always check the adjoining pipework and fittings before ordering.
What Is the Product Code?
The product code is ZL-7201-1M.
At What Temperature Does It Open?
The valve opens at approximately 3°C.
At What Temperature Does It Close?
The valve closes again at approximately 4°C.
Does the Antifreeze Valve Need Electricity?
No.
It operates mechanically and does not require an electrical supply.
Is It Suitable for a Monobloc Heat Pump?
Yes, it can suit compatible water-based monobloc ASHP installations.
However, always check the heat pump manufacturer’s frost-protection requirements.
Should I Fit One on the Flow and Return?
Many heat pump layouts use antifreeze protection on both exposed flow and return pipework.
However, always follow the specific heat pump manufacturer’s installation instructions.
Can I Use This Instead of Glycol?
Potentially, but only where the heat pump manufacturer and system design allow antifreeze valves as the frost-protection method.
Do not remove or replace glycol without checking the system requirements.
What Is the Maximum Working Pressure?
The published maximum working pressure is 10 bar.
What Is the Working Temperature Range?
The system-water working range is 0°C to 65°C.
The ambient operating range is -30°C to 60°C.
What Is the Kv Value?
The published Kv value for the 1″ version is 55m³/h.
Is a 28mm Version Available?
Yes.
Kudos Trading also stocks the 28mm ASHP Antifreeze Valve.
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Next Working Day Delivery
Yes, we hold all our products in stock at our 7,000 sq ft Nottingham warehouse and at our 3,000 sq ft warehouse in Market Harborough.
We use DPD for tracked next-working-day delivery.
Collection Available
You can always collect from our Nottingham location and help yourself to a free tea or coffee.
