If you smell gas, a carbon monoxide (CO) alarm sounds, or anyone may have symptoms of CO poisoning, leave first and call 911 from a safe place. Do not use switches, phones, or anything that could make a spark nearby. Then call your gas utility or propane company.
Suncoast repairs and installs Hayward gas pool heaters that run on natural gas or propane. We work at homes in Sarasota and Manatee Counties. A Hayward that stops heating does not always need replacing. Colin checks it first. He confirms the exact model and your address before he books the work. Suncoast is an independent service company. We are not a Hayward authorized dealer, warranty center, or manufacturer-certified service provider.
Call Colin at 941-961-9337. There is no online form on this page. Keep the cabinet closed and use only the visible details described below.
From model to message to next step
Follow these steps in order. Use the links to jump to the part of this page that helps.
Check for danger firstGas smell, smoke, fire or a CO alarm? Leave and call from a safe place. Skip the rest.Safety steps
Find the modelRead it from the label on the outside of the heater. Do not open a panel.Model list
Copy the messageWrite every letter and space. Note if it is steady or flashing, and if it came from the heater, a control system or an app.
Match bothFind your model, then your message. No match? Do not borrow a meaning from another model.Message lookup
Take the next safe stepNote only what you can see from where you stand. Then call Colin with the model and the message. A technician finds the cause.
Hayward repair: check before you replace
Your heater may not fire, or it may show a code. That is a good place to start. It does not prove that a part, or the whole heater, is done. Hayward's Universal H-Series service and installation manual lays out step-by-step checks before naming a cause. Colin checks the heater, the water flow and the gas supply on site. He explains what he found and gives you a price. Then you decide between repair and replacement. Pool heater repair
Hayward replacement or new install
If replacement makes more sense, the review covers the new heater's size and fuel, the gas supply, the pad, and how the heater connects to your pump and controls. A new Hayward is not assumed to fit where the old one sat. Installation and replacement
Which Hayward heater do you have?
Universal H-Series for in-ground pools and spas. Hayward's service and installation manual covers this family.
H-Series heater for above-ground pools. Hayward has a separate manual for this version.
Copy the exact model shown on the outside label. Two heaters can look alike and still be different models or fuels. If you cannot read a model without opening the cabinet, leave it. Colin can identify it on site.
What does a Hayward heater code mean?
Hayward gas pool heaters show two-letter codes on the display. Some codes report a fault. Some are normal, and some look like words but mean something else. LO does not mean low temperature. A code points to what the heater sensed. It does not prove which part failed. The message lookup below explains each code by model, with the manual page.
LO alone does not show which switch opened. Only testing can show that. One possible cause is a tripped exhaust limit switch. If testing finds that trip, Hayward says the heat exchanger is damaged. The heat exchanger is the set of tubes that heat the water. Low water flow or poor water chemistry is the usual cause. Hayward warns that running the heater after this trip will damage the whole unit (Rev T, p. 57).
Message lookup by model
Find your model, then your code. Each card gives the exact code, what it means, what the manual checks, what you can safely note, and the page it comes from. A code is a clue. It does not prove which part failed. A call for heat is when the control asks the heater to warm the water. Lockout means the heater stops trying for a set time or until it is reset.
Universal H-Series H150FD to H500FD
These cards use Hayward's service manual 1301623301 Rev T. Hayward's owner's manual 51300004201 Rev E uses the same letters, but some descriptions differ.
LO
Fault or normal
Applies to
Universal H-Series H150FD to H500FD
What it means
The limit string is open. That is a chain of safety switches that must all be closed before the burner can run. LO does not mean low temperature.
What the manual checks
Hayward says LO is normal when the pump is off and should clear once the pump runs. If it does not clear, Hayward's steps go to water flow, then to the switches and wiring.
What you can safely note
Was the pump running when LO showed?
Technician's part
Only testing shows which switch opened. If testing finds the exhaust limit tripped, Hayward says the heat exchanger is damaged and running the heater will damage the whole unit.
The blower vacuum switch is open. This switch proves the fan (blower) is moving air. AO can show at start-up, while running, or after the burner shuts off.
What the manual checks
Hayward's chart checks the switch tubing, the switch and fan wiring, the fan and its relay, and then the switch.
What you can safely note
From where you stand, are the air openings blocked by plants or stored items? Do not reach in.
These heaters have a newer display and their own code table. Some codes share letters with the older heaters but are handled in a different way. Use this manual, not the older Rev T charts.
H icon, gray or solid black
App status
Applies to
OmniX models on the cover of manual 51301060001 Rev D, such as HS135FD to HS500FD and W3HS135FD to W3HS400FD
What it means
Gray means the heater is ready to be claimed in Hayward's OmniX app. Solid black means it has been claimed and set up in the app.
What the manual checks
This icon is about app setup. It does not report a heater fault. Bluetooth works near the heater. Control over the web needs Hayward's separate OmniX Gateway.
OmniX models on the cover of manual 51301060001 Rev D, such as HS135FD to HS500FD and W3HS135FD to W3HS400FD
What it means
The limit string is open. If the heater is not calling for heat and the fan is off, the control reads LO as the water pressure switch opening. It waits and does not lock out. During a call for heat, it treats LO as an open heat limit or vent switch and locks out.
What the manual checks
Hayward also warns never to run the heater with the pump off.
What you can safely note
Was the pump off? Was the heater trying to heat?
Technician's part
A technician uses this manual's table, not the older charts.
The Universal HC Series with OmniX, models HDFS275 and HDFS400, has a separate manual and different codes, such as L1 to L4. This page does not explain them.
Not listed? Your code may still be real. Do not borrow a meaning from another model. Write down the exact letters and the full model, and give both to Colin.
Planning a new Hayward heater: questions to settle
These questions come from Hayward's Universal H-Series manuals. They show what the installer must check. They are not steps to do yourself. Gas, vent and wiring work belongs to a qualified installer, under local code.
Natural gas or propane?
Hayward's gas pipe tables list natural-gas models with N at the end, such as H250FDN, and propane models with P, such as H250FDP. Hayward says only a qualified service agency should change a heater from one gas to the other, using its kit.Universal H-Series service manual (1301623301 Rev T), pages 21 and 44
Is the gas line big enough?
Hayward sizes the gas pipe by the heater's size, the fuel, and the distance from the meter or tank. The installer checks your line against those tables.Universal H-Series service manual (1301623301 Rev T), page 21
Where will it sit outdoors?
Outdoors it is self-venting and needs no added vent pipe. Hayward says not to put it under a deck, where sprinklers can spray it, or where shrubs may grow over its air openings.Universal H-Series service manual (1301623301 Rev T), page 11
Hayward says a chlorinator must go after the heater, with a check valve between them. It also says not to put chlorine tablets in the skimmer. Damage from poor water balance is not covered by its warranty.Universal H-Series service manual (1301623301 Rev T), pages 7 and 8
If you smell gas, see smoke or fire, or think carbon monoxide is possible, do not stay to take photos. Move everyone away. Then call from a safe place. If you see smoke or fire, call 911. If carbon monoxide is possible, get to fresh air and call 911. If you smell gas and the heater uses natural gas, call 911 and your gas utility. If you smell gas and the heater uses propane, call your propane company, or 911 or the fire department.
When none of that applies, send a wide photo of the whole heater. Then send a close photo of any label or display you can already see. Write any code exactly as shown. Add the serial number or fuel only if a label states it. Leave all panels on.
What a repair visit costs
A repair visit is a service call. You hear the fee before the visit. It pays for Colin's first hour of on-site checking and testing. It is due even if you turn down the repair. After that you get a total-price quote, good for 15 days from the date it is issued. No repair or installation work starts until you approve that price. Full fee and quote rules
Call Colin at 941-961-9337, Monday to Friday, 8 AM to 5 PM.
Sources and limits
The message lookup and install planning notes above come from these manufacturer manuals. Each card and answer names its manual and page. The manual copies used here were retrieved on the date shown. A manufacturer can change a manual later, so check the manual for your own heater too.
