What is the thermosyphon effect?
The thermosyphon effect is a naturally driven circulation of fluid caused solely by temperature-induced density differences—no pump required! It’s a beautifully simple and powerful phenomenon.
Here’s how it works:
When water is heated, it becomes less dense and rises.
When it cools, it becomes denser and sinks.
Connecting the hot and cold regions with a loop or pipe creates a continuous, self-sustaining flow.
Why it’s useful
No moving parts → highly reliable
No electricity needed → energy-efficient
Automatically adjusts flow based on heat input
Getting the most out of your coil
Keep your hoses short and tidy.
Use only the hose length needed to maintain a straight, direct run to your coil. Avoid any sagging that could trap air or reduce flow.
Prevent leaks wherever possible.
Use the supplied jubilee clips to secure the hose to your coil (and to the brass connectors if you’re using them). For any threaded fittings, wrap plumbers’ PTFE tape around the threads to keep everything completely watertight.
Keep air bubbles out of the system.
Leaks let water out—but they also let air in. To reduce the chance of bubbles forming, ensure your connections are tight. It also helps if the hose from the top of your coil back to the tub has a slight upward incline, encouraging any trapped air to rise back into the tub.
If you suspect an air bubble, gently tap or shake the hose or coil to help release it.
Never run the coil dry — ever.
Do not light a fire in a coil that isn’t fully connected to a water-filled hot tub. Do not allow the fire to continue if the warm-water outlet slips below the water line. Without proper water flow, the coil and its attachments can overheat rapidly, causing any water inside to boil and build dangerous pressure.
This is extremely hazardous.--
Additional ways to speed up your heating time:
Use a well-fitted hot tub cover and keep it on while the water is heating.
Add insulation to your hot tub whenever possible.
Burn well-seasoned, dry wood or a similar clean-burning fuel; it produces hotter fires with far less smoke..
