The air discharged from spa and spa bath injectors can sometimes feel noticeably hot or cold. This is generally related to the blower's design, the number and size of air outlets, and the amount of backpressure within the air system.
Why Does the Air Feel Cold?
Cold air is common in systems with a large number of air injectors. As air exits the injectors, its pressure drops rapidly. Combined with the relatively cool ambient air drawn into the blower, this can produce a noticeable cooling sensation.
Even heated air blowers can produce air that feels cool after running for a short period. Their heating elements help reduce the cold sensation but do not necessarily maintain a consistently warm temperature at every injector, particularly in systems with high airflow or numerous outlets.
Can Cold Air Be Reduced?
Reducing cold air can be difficult, but possible options include:
- Installing a more powerful blower, provided it is suitable for the existing plumbing and injector arrangement.
- Installing a heated air blower, which incorporates an electrical heating element to warm the discharged air.
Why Does the Air or Injector Feel Hot?
Warm or hot air can have two main causes:
- Heated blower: Some air blowers incorporate an electrical heating element that intentionally warms the discharged air.
- Excessive backpressure: Too few injectors, undersized outlets or restricted pipework can cause pressure and heat to build up within the blower. This can result in unusually warm air and hot injector fittings.
It is also possible for the air to initially feel hot or warm before cooling as the blower continues operating. This temperature change alone does not necessarily indicate a problem.
Can Hot Air Be Reduced?
Depending on the installation, possible solutions include:
- Removing or disconnecting the heater: Where the blower's design permits, the internal heating element can be disconnected or removed by a licensed electrician.
- Increasing air outlets: Adding additional injectors or increasing the outlet area can reduce excessive backpressure.
- Installing an air bypass: A suitably designed bypass or pressure-relief arrangement, usually incorporating a valve after the blower discharge, can allow some of the air to escape safely elsewhere, reducing backpressure within the system.
Every Spa and Spa Bath Is Different
Blower capacity, pipework, injector sizes, water depth and overall system design all influence air temperature and performance.
There is no universal solution. Some installations require additional plumbing modifications, specialist components or changes to the original system design.
Air temperature can also change during operation. For example, the initial burst of air may feel quite hot or warm before gradually becoming cooler. This can occur even with a heated air blower and does not necessarily indicate a fault.
Important Information
The information provided above is general guidance only.
HASP cannot determine exactly what modifications are required. Any changes must be assessed and undertaken by an experienced, suitably qualified technician.
All electrical modifications must be performed by a licensed electrician. Heating elements should only be disconnected or removed where permitted by the manufacturer's design and instructions.
Excessive heat should not be ignored. Significant backpressure can cause blower overheating, premature failure or damage to equipment. Affected equipment should be switched off and inspected before further use.
