Why Does My Pool Heater Keep Shutting Off?

A pool heater shutting unexpectedly could be a nuisance to you, especially on those days you prefer to spend more time in the pool. If the pool is for commercial purposes, you lose bucks from your customers.

You can solve the problem of the pool heater shutting off using a few solutions. Let’s first find out what could cause the heater to trip off.

What causes pool heater to trip off?

Unusual turning off and on a pool heater shows there’s something wrong, and the heater system needs fixing. Below are reasons why the heater keeps turning off and on:

1. Blocked impeller

Sometimes debris from water deposits itself on the impellor, causing a blockage. When the impeller is blocked, its fun can’t rotate to pull water from the filter. Pool heaters must have water for heating, and when there’s no water supply, the heater will turn off.

2. Less voltage supply

A pool heater’s mortar requires enough voltage supply to heat the water; if not, the heater turns off. Loose wires or improper wiring leads to low voltage.

3. Less power supply

Electric gadgets have their power supply required to run. When the mortar receives less power energy, it won’t turn on.  If the heater was running then suddenly stops, check the amount of power supply and disconnect any appliances from your home consuming more power.

4. Overheating

A pool heater has a thermostat to regulate the heat supply to the heater. Excess heat supply causes the thermostat to break its circuit to prevent more heat from getting to the heater; hence it turns off.

Pool heater problems

For a perfect working pool heater, all internal parts must be in excellent condition. If not, the heater stops functioning. Various internal defects may arise, stopping the normal functioning of the heater. Below are heater problems pool owners experience.

1. Heater shuts off before reaching the desired temperature

Sometimes, you turn on the heater, it works but shuts before reaching the desired temperature to keep the pool water warm. In this case, incorrect thermostat settings and a smaller heater than the size of the pool are the culprits.

A thermostat setting of a lower temperature than the pool’s water causes the thermostat to stop after reaching the set temperature.

A small heater heating a large quantity of pool water will not heat all the water uniformly to the desired temperature because it has a low heat supply.

2. Heater won’t turn on

Internal defects in a heater will make it not turn on, however much you try.  Possible reasons why the heater won’t turn on are:

• Clogged dirty filters- debris deposits on the filter prevents the fun from sucking in water for heating.
• Closed gas supply valve- Gas is an essential ingredient to run a heater because the gas heats up to warm the water from the pump. When the valve is closed, no gas enters.
• Closed filter valve and plumbing valve- These valves allow water to enter for heating. Closing them prevents water from entering the heater.
• Incorrect temperature setting-  When the temperature setting on the thermostat is lower than the pool water temperature, the heater refuses to turn on.

3. Cycling

Faulty and corroded parts of a thermal regulator, pressure sensor, and the high limit switch cause cycling. Unbalanced water chemicals (e.g., chlorine) to pool water ratio could also cause cycling.

4. Leaking

Leaking isn’t a common problem in heaters, but sometimes it happens. When operating, a hot gas heats the water, and because of high temperatures, some water evaporates as gas and later condenses back to water when they fall on a cooler surface of the heater. Before fixing the problem, use the below procedure to confirm if your pool heater is leaking and not a normal condensation process.

• Turn off the pool heater and other pool equipment.
• Allow the heater area to dry up.
• Turn on the pool water equipment. The pool heater should be left turned off.
• Wait for about 15 minutes to check for any water deposits. Water deposits show leaking. If it’s dry, there’s no leakage.
• Turn on the heater
• Let it run for about 10-30 minutes.
• If there are water deposits, it shows a normal condensation process and no leakage.

5. Pilot not lighting up

if there’s less air supply, improper venting, and low gas pressure, the heater pilot won’t light up. When the air supply is less than the required amount, an electric heater won’t warm it up, which prevents the pilot from lighting.

6. Noise

Pool heaters sometimes produce an annoying, grinding sound. This noise is produced for three reasons: clogged, dirty systems, loose parts, and faulty pressure switches. Dirty systems make the heater overstretch while heating the water, producing noise.

7. Uneven heating

Some sections of the pool water may sometimes feel warmer, while others feel colder. This problem is caused by small, dirty, clogged filters and a smaller heater than the recommended pool water quantity.

A smaller heater than the pool water will only heat part of it, while a dirty, clogged filter lets in smaller quantities of water for heating hence the unevenness in pool water temperatures.

How to fix a pool heater?

Before calling an expert to help fix heater problems, you could try a few of these troubleshooting methods.  Check the below solutions to correct your pool heater problems.

1. Clean the filters and set a higher  temperature

Cleaning debris off the filters allows water to flow into the heater, and it will turn on.

To clean off the debris, rinse the filters under hose water.

 Set the thermostat temperature higher than the pool’s water temperature. Be sure to open the filter, gas, and plumbing valves.

2. Install the correct heater size and set a higher temperature

To correct a heater that won’t turn on, install the correct heater size for your pool so that the heater can work with the required water quantity. It’s wise to install a bigger heater than the recommended size for your pool for faster heating.

Set the thermostat temperature higher than the pool’s water temperature.

3. Check for corroded parts and clean them

Check the pressure sensor and thermal regulator parts for any corrosion and clean. If the parts are badly corroded, replace them with new ones.

4. Consult an expert

If your heater is leaking, it’s best recommended to call an expert to fix the problem. Leaking parts of a heater can be fatal if the gas leaks to the surrounding.

5. Add more fuel

To fix a pilot that won’t light, add more fuel to the tank to increase gas pressure. Also,  open the valve to let in more air. Check the tubing, and if it’s loose, tighten it. Check for clogging on the pilot orifice. If there is, rinse it with hose water.

6. Remove debris and tighten loose parts

Carefully remove the filter and clean off the debris from it. Use clean water from a hose.

If there are any loose parts, tighten them up.

7. Fix a bigger heater and clean up

If the heater is smaller to heat a large quantity of pool water, get a bigger one to heat the water faster and evenly.

 The clogged dirty system causes uneven heating; rinse the filter parts using hose water to remove the debris deposits.

Sources and References

• Office of Energy Efficiency & Renewable Energy: Gas Pool Heaters.