Hot Tub Heater Not Working

Is your hot tub heater not working, keeps switching off or taking a long time to heat up? A hot tub should be hot. Check out the most common problems below. The issue could be down to a simple reason that you can check and maybe easily fix yourself. Otherwise, consult a specialist. 360 Hot Tubs provide repairs and servicing throughout Southampton, Portsmouth, Guildford, Bournemouth,  Hampshire and Dorset.

Remember that water and electricity are an extremely dangerous combination. Use the guide below at your own risk. For your own peace of mind, get in touch with our hot tub specialists.

Hot Tub Heater Not Working and Possible Reasons

1. Are there any error codes?

   These could be flo, dr, dry, Oh, Ohh, FL1, FL2, SNS, or a mixture of flashing dots. Jump to the list of error codes. Be sure to mention any error code when calling a us about your heater not working. This could help us diagnose over the phone and bring the right parts to fix the problem.

2. Is the water level correct?

   Check to see if the water level in your hot tub needs topping up. The water level drops through evaporation and from splashing out over the sides. When the water levels are too low, the hot tub skimmer can draw in air instead of water. This causes the heater to cut out as not enough water is passing through it. A good guide is all jets covered and a good amount of water flowing through the filter housing.

3. Have you recently filled your hot tub?

   Although this varies, a newly filled hot tub can take several hours to heat up.

4. Are the filters clean?

   The hot tub filter catches dirt and debris and can restrict the water flow when clogged. Ideally, the filter should be checked and cleaned weekly and replaced annually. Try removing and cleaning the filter to see if it fixes the issue.

5. Check there is power to the spa

   Check the hot tub has power from the main fuse box in the house and any switch between is turned on.

6. Is the circulation pump running?

   If the pump is not working properly it will stop or restrict the flow of water around the hot tub. This will cause the heater to cut out. The pump may need repairing or replacing.

7. Hot tub element fault

   If the hot tub is tripping the electrics when it calls for heat this could be a faulty element.

8. Pcb fault

   If the pcb or control box has a fault it may need to be replaced.

9. Check pressure switch

   The pressure switch or flow switch is can be found on the heater or circulation pump plumbing. We strongly recommend using the services of a hot tub engineer or a qualified electrician to test this for safety reasons. If the pressure switch is faulty it will need to be replaced to fix the issue.

Hot Tub Error Codes Connected to Heater Not Working – and how to fix them

Flo – The Flo error code usually means the hot tub has a low or no water flow issue. You can try the following yourself before calling a hot tub repair specialist.

1. Check the water level
2. Release pump airlocks
3. Check the filter, pump and valves for any obstructions
4. Clean the hot tub filter
5. Is the pump working?

Dr/Dry – The Dr/Dry or “HEATER MAY BE DRY WILL RETEST SHORTLY” error code means the hot tub heater has detected inadequate water levels. You can try the following yourself before calling us out.

1. Check the water level
2. Add water to the correct level and restart the pump and heater

OH/OHH/OHS – OH/OHH/OHS overheat error codes mean that a hot tub temperature sensor has detected an unsafe water temperature and the heater shuts off. The water probably isn’t flowing fast enough through the heater causing the temperature to increase. DO NOT USE THE HOT TUB while these error codes are flashing as the water could be scalding hot. You can try the following yourself before calling us out.

1. Open the spa cover to allow excess heat to escape
2. Remove any floating cover
3. test the water temperature with a thermometer to get a true reading
4. Clean the filter cartridge
5. Check water levels
6. Reset the hot tub

Fl1 – Fl1 error code could mean the hot tub is pointing to a potential air lock issue or dirty filter. The spa isn’t sensing enough water flow to close the pressure/flow switch. You can try the following yourself before calling us out.

1. Check the water level
2. Clean or replace filters
3. Is the pump running?
4. Remove a panel and check the flow switch is connecting

Fl2 – Fl2 error code means the pressure/flow switch is malfunctioning or is stuck closed. The heater will stop working and likely the jets too. You can try the following yourself before calling a hot tub repair specialist.

1. Check the water level
2. Clean the filters
3. Remove a panel and check the flow switch is connecting

SnS – SnS error code means the hot tub sensors are out of balance. It could just be a temporary problem if the temperature of the spa is also being displayed. You can try the following yourself before calling us out.

1. Reset the spa

Mixture of flashing dots – Usually means the hot tub heater has inadequate water flow or the pressure/flow switch may be defective. You could try the above recommendations or call us out.