Hot tub control systems
Updated October 2026
The control system runs everything in your hot tub: the heater, pumps, lights and safety cut-outs. Here’s what’s inside it, what tends to fail, and how we decide whether to repair or replace it.
The parts of a control system
- Control pack
- The main box in the cabinet. A circuit board with relays switches the pumps, heater, blower and lights.
- Topside panel
- The keypad on the tub’s edge. It sends your settings to the pack and shows its messages.
- Sensors and switches
- Temperature and high-limit sensors, and a flow or pressure switch, tell the pack if it’s safe to heat.
- Heater
- Usually a tube next to the pack. It only runs when the pack can see water flowing through it.
Common control faults
| What you see | What it often is |
|---|---|
| A blank topside | No power to the tub, a blown fuse on the board, or a failed topside or cable. |
| A code on the display | The pack has found a problem. Look it up first: hot tub error codes. |
| Pumps run, but no heat | A flow switch, sensor or heater fault, or a relay that’s stopped switching. See hot tub not heating. |
| A pump that won’t switch off | A stuck relay on the board. Switch off at the isolator and call us. |
| The RCD trips | Often the heater or a pump, rather than the pack itself. See hot tub tripping the electrics. |
| Buttons that don’t respond | Water in the topside, or a damaged cable. |
There are mains voltages inside the control pack. Don’t take the cover off. Switch off at the isolator before you open the cabinet.
Repair or replace?
We find the failed part before we suggest anything. A sensor, fuse, relay or topside can often be replaced on its own.
If the board itself has failed, or parts for an older pack are no longer made, a new control pack can be fitted. It has to match your pumps, heater and topside, and we’ll explain the options and the cost before we order anything.
A replacement topside sometimes needs a new overlay (the printed sticker on the keypad) so the buttons match your tub.
Wi-Fi modules
Balboa, Gecko and SpaNet all make Wi-Fi modules that let you check the temperature and change settings from your phone. They plug into the control pack, so they only work with a compatible pack and software version.
Tell us the make and model of your pack (it’s on the label on the box) and we can check whether a module will work before you buy one.
New control panels fitted
From 47 reviews on Google
“Jon installed a new control panel and overlay to my Marquis Hot Tub excellent job and even managed a modification that the manufacturer had not allowed for. Any future problems and he will be the first person I call.
Nigel Lace, Penryn Cornwall”
“Thank you for coming out in the rain to repair our hot tub. The new control panel is working fine it was nice to meet you and I will recommend you to my friend and family who have hot tubs it’s Sunday afternoon and we are looking forward to going in the tub with a glass of wine. Thank you once again Mike and Cathy at lanlivery”
“⭐⭐⭐⭐⭐
Excellent service from start to finish. My hot tub needed repairing, and everything was explained clearly, including the fault, how to maintain it properly, and how to keep it running efficiently. The price was reasonable, too, with honest advice and no unnecessary extras.
Really helpful, knowledgeable and happy to answer questions. I’d definitely recommend him to anyone needing hot tub repairs or maintenance in the local area.
Thank you for getting my hot tub sorted! 😊”
Control system fault?
Switch off at the isolator, then ring or WhatsApp us with a photo of the panel or the label on the control pack.
If your tub is sunk into decking or the ground, or set against a wall, it helps to mention it when you book. If you’re not sure, a photo is fine.
Where we work
We’re based in Tuckingmill, Camborne, covering Mid and West Cornwall, from Bodmin and Newquay to Penzance and everywhere in between. Towns we cover include:
See the 18 towns we cover
Somewhere else in Cornwall? Just ask. Every area we cover