Description
The Tecmark 4000 Series 21A Pressure Switch delivers reliable heater activation control for spa systems. Constructed with durable plastic housing on both top and bottom, this switch features standard 1/8" MPT threading and dual spade terminals for straightforward electrical connections.
Engineered with an impressive 21 Amp capacity, this switch accommodates high-demand 115V plug-and-play spa configurations where heater power runs directly through the switch mechanism. While most air button activated switches handle minimal relay loads under 1 Amp, this heavy-duty model supports both high-amperage and standard low-amperage applications, making it a versatile replacement option.
Compatible across multiple control system brands including Balboa, Gecko, ACC, Hydroquip, Len Gordon, Maddux, and other standard spa heater assemblies. The universal design ensures broad fitment for most hot tub heating tubes.
Common failure modes include switches that remain open when circulation pumps activate and pressurize the system, or switches that fail to open when pumps deactivate. Either condition typically triggers no-heat or overheat error codes. Before replacement, verify your circulation pump operates properly and filters aren't blocked, as these conditions can also trigger flow errors.
The 21 Amp rating provides downward compatibility—this switch works perfectly in both high-amperage and low-amperage installations, whereas standard 1 Amp switches only function in minimal-load applications.
| Switch Type | Pressure |
| PSI Rating | 1 to 11 psi |
| Manufacturer | Tridelta/Tecmark |
| Plumbing Connection Size | 1/8" |
| Plumbing Connection Type | Male National Pipe Thread (mnpt) |
