This page explains hydro-heat.pdf, the component diagram in the /walk-in-tub/schematics/ folder that shows the Soaking + Heated Seat & Back configuration (revision 05-06-24). It is the one schematic in the set with no pump on it, and the only one that prints 15 AMP. You will learn why the file name is misleading, what its three components are, how the keypad, heater box and pads connect, and why nothing on this page heats the water.

A File Name That Does Not Match Its Contents

The file is named hydro-heat.pdf, which suggests a hydro massage package with a heated seat. Open it and the title reads "Soaking + Heated Seat + Back". There is no hydro pump, no in-line water heater, no ozone generator and no jets of any kind on the page. The diagram prints no "Available With" list either, so it is not tied to a particular model; it applies to an Ella walk-in tub ordered as a soaker (no jets) with the Heated Seat and Backrest option. If you actually have hydro jets and a heated seat, your diagram is one of the hydro plus heated seat pages instead, such as the Standard, Flow and Zen hydro schematics. Soaking configurations in general are described on the soaking-only walk-in tubs page.

The Three Components

The legend prints exactly three items:

Those same three items appear as components 4, 5 and 6 on the Standard, Flow and Zen hydro plus heated seat diagram and as the last items on the LayDown air and microbubble heated seat diagrams. The heated seat chain is drawn the same way wherever it appears; this page simply shows it on its own. The option is described from the bather's point of view on the heated seat and backrest page.

How the Heat Keypad, Heater Box and Pads Connect

The diagram's chain runs in one direction:

1. The Surface Key Pad (the Heat Keypad) is the ON/OFF push button the bather presses.
2. The keypad signals the Surface Heater Box, the heat control box.
3. The Surface Heater Box powers the Surface Heater Pads, one set for the seat surface and one set for the backrest surface.

That is the entire signal chain. If the pads never warm, the three places to look are the keypad, the box and the pads themselves, in that order. There is no relay switch, no control box for pumps and no load outputs on this page, because there is nothing else to control.

Why This Diagram Prints 15 AMP

Every other therapy schematic prints "20 AMP, 120 Volts" on its outlet block, and the multi-system packages print two or three such outlets. This diagram prints "15 AMP, 120 Volts". The difference is the absence of pumps: a soaking tub with a heated seat has only the surface heater pads to power. The spec sheets that list the Heated Seat and Backrest as an option rate it at 4AMP. As always, the page closes with "Please View Specifications for Electrical Amperage (A), Voltage (V) and Wattage (W)", so your model's spec sheet remains the document for load figures, and your electrician should follow it and local code. A model-by-model summary is on the electrical requirements page.

Nothing on This Diagram Heats the Water

This is the most common misunderstanding about the heated seat option, and the diagram makes it plain. There is no in-line water heater on the page. The surface heater pads warm the seat and backrest surfaces you lean against; they do not warm the bath water. Warm water comes from your home's water heater through the faucet, and on a soaking tub there is no jet loop for an in-line heater to sit in. If staying comfortable during fill and drain is your concern, the practical tips are on the page about staying warm while the tub fills or drains; the heated seat and backrest is the feature designed for exactly that moment.

When to Cite This Diagram

Use hydro-heat.pdf when:

1. The order shows a soaking (no jets) configuration with the Heated Seat and Backrest option.
2. An electrician asks what the heated seat on a soaker needs, and you want the diagram's own 15 AMP, 120 Volts callout alongside the spec sheet's 4AMP option rating.
3. A bather reports the seat is not warming and you want to name the keypad, heater box and pads by their printed component numbers when contacting the team.

Do not use it for a tub with hydro or air jets, even though the file name says hydro. For those, the heated seat components appear on the package's own diagram with the pumps drawn in. If you are not sure which configuration you have, the team can confirm it from your order at ellasbubbles.com/support or (800) 480-6850.

Download the official document: Soaking + Heated Seat & Back Component Diagram

Common Questions