What Raypak Heater Error Codes Mean and How to Fix Them

If you’ve ever glanced at your Raypak heater and seen codes like BD1, PRS, or HL1 blinking back at you, we understand how confusing they can be. Half the time, it feels like the heater is talking in its own secret shorthand.. Especially, when you’re just trying to keep your pool warm enough.

The reality, each code offers a way of flagging a specific issue: low water flow, a sensor problem, overheating, ignition trouble, or in some cases, a failing internal board. Some of these you can safely troubleshoot yourself. Others mean your heater is protecting itself from real damage. Some protect you from a safety hazard.

This article is all about helping you understand your Raypak heater’s error codes not selling you something you may not need. But if one of these codes points to a part that’s truly failed, you’re never on your own. Shasta Pool Supply stocks a full range of Raypak heaters and replacement parts, so you can get what you need without waiting weeks for backorders. And because every pool system is a little different, our team of local experts can help identify the exact component your heater requires. It’s part of our promise as Arizona’s most trusted pool care partner: clear answers, honest guidance, and the right equipment when you need it.

The upside is that once you know what the codes mean, you can tell which problems are simple and which ones need a pro. In this guide, we’ll break down the most common Raypak error codes we see across Phoenix Valley homes, what causes them, and what you can safely do next.

Your heater may be flashing “SERVICE,” but with the right information, you don’t have to guess what’s going on.

When your heater spots trouble, it doesn't stay quiet about it. The word "SERVICE" starts flashing on and off across the display panel. Your heater's way of saying "Hey, I need help here".

Right alongside that flashing warning, you'll see a three-letter code pop up in the lower left corner of the display. These codes – things like BD1, EEP, FFL – aren't random letters. Each one points to a specific problem affecting your heater's performance.

Some Raypak error codes signal minor hiccups. Others scream that something serious is wrong with your heater. Here are the critical codes that require immediate action and what you can actually do about them.

BD1: When Your Main Board Dies

BD1 means your heater's brain just stopped working. The main processor failed to start, which is as bad as it sounds. Before you panic about replacement costs, try this first:

• Kill power at both the toggle switch and the main source
• Wait a few seconds, then restore power
• Watch the display – if BD1 comes back, your board is toast and needs replacement.

This reset works about 30% of the time. If it doesn't, you're looking at a service call.

EEP: Memory Failure (And Why Resetting Won't Help)

EEP tells you the heater's memory couldn't start up properly. The system can't run its program because the data it needs isn't accessible. You can try the same power reset as BD1. If EEP returns after the reset, your board has failed and replacement is your only option.

FAN: Airflow Problems That Shut Down Your Heater

FAN errors point to two possible culprits: lost pilot flame or a faulty air pressure switch. If your heater has a serial number before 0707, it's almost always pilot loss during operation.
Check these before calling for help:

• Verify the fan relay is getting proper power (120V or 240V)
• Inspect the tubing between fan housing and switch for kinks or damage

Your heater will attempt three times before giving up, then automatically try again after five minutes.

FFL: False Flame Detection (Usually a Gas Valve Issue)

When FFL appears, your heater thinks it sees a flame before it's supposed to. This typically happens when:

• The pilot stays lit after heating stops (gas valve problem)
• Pilot system components malfunction
• Main board starts reading false signals

Start by checking if your pilot flame stays on after the main burner shuts off. Also inspect and clean the ground wire connection. Dirty connections cause more false readings than you'd expect.

GVC & GVO: Gas Valve Control Gone Wrong

GVC means your heater sent a signal to open the gas valve but detected no power at the pilot valve (PV) or main valve (MV). GVO is the opposite – power showed up at a valve when it shouldn't be there. Both codes often trace back to insufficient transformer power. If you're getting less than 240V AC to the transformer, these errors become common.

Most of these issues can be resolved with proper troubleshooting, but some require professional expertise. For persistent problems or if you're uncomfortable with gas valve diagnostics, Shasta Pools Supply's technicians at our Phoenix, Mesa, and Surprise locations can offer complex repair guidance.

When repair costs keep adding up, replacement may be the smarter long-term choice. Explore our Pool Heater Options & Their True Costs article.

Water issues with your Raypak heater fall into their own category of headaches. These problems usually mean your heater detected something wrong with water flow, pressure, or temperature and shut itself down as a safety precaution.

PRS: Your Heater Can't Feel the Water

When you see "PRS" on your display, your heater is basically saying it can't detect enough water pressure. This happens more often than you'd think.

Check your skimmer first. If the water level dropped below the middle of the skimmer face, that's your problem right there. Your pump might not be running properly either. Start by checking your filter pressure and backwash if needed.

Here's something many pool owners don't realize: if your heater sits more than 5 feet above or below your water level, the pressure switch might need adjustment. That's not a DIY fix for most people.

HL1 & HL2: When Your Water Gets Too Hot

Both HL1 and HL2 mean the same thing – your water temperature shot past 135°F. That's way too hot and potentially dangerous.

These limits usually reset themselves once the heater cools down. However, something caused the overheating in the first place. Common culprits include blocked tubes, restricted water flow, or problems with your Unitherm governor. You might also need to check the bypass assembly and replace the spring or bypass components if they're worn out.

SNS: Sensor Problems That Drive You Crazy

Sensor failures show up when temperature readings go completely out of whack. This code appears if your water temperature drops below 36°F or climbs above 110°F. SNS also triggers when your two thermistors disagree by more than 2 degrees.

The usual suspects? Loose connections at P1 on your circuit board or sensors that aren't seated properly in the JACO fitting. These are frustrating because intermittent connection problems can make your heater work fine one day and act up the next.

ROL: When Flames Go Where They Shouldn't

ROL means your thermal fuse tripped because it detected excessive heat or flame rollout. This is a critical safety feature that prevents dangerous overheating situations.

What causes this? Downdraft can push flames around where they don't belong, clogged exhaust passages in your heat exchanger restrict airflow, or blocked venting creates back pressure. These aren't problems to ignore or try fixing yourself.

If you're dealing with persistent ROL errors or any of these water-related codes, Shasta Pools Supply in Phoenix Valley can diagnose what's really going wrong. Our locations in Phoenix, Mesa, and Surprise have the expertise to get your heater running safely again.

Learn more from our team about why Raypak created Protek Shield — visit Raypak ProTek Shield vs Traditional Methods

Nothing's more frustrating than walking out to check your pool heater only to find a completely blank display staring back at you. No codes, no messages, no signs of life whatsoever.

This isn't about decoding cryptic three-letter messages anymore. When your display goes dark or your heater refuses to start, you're dealing with fundamental power or system issues that require a different approach.

Dead Display? Check Your Breakers First

A blank display usually means one thing: power problems. Before you assume the worst about your heater, take a walk to your electrical panel. Look for any tripped breakers and reset them if needed.

Once power is restored, check if your transformer is outputting the right voltage. You should see 24V AC coming from either a 120V or 240V input source. No voltage? Your transformer likely needs replacement.

IGN & ILO: When Your Heater Can't Light Up

IGN and ILO codes mean your heater tried to ignite multiple times but failed each attempt. For natural gas heaters, this often points to gas supply issues or faulty ignition components.

Propane users face a specific challenge here. When your tank drops below 30% capacity, pressure becomes insufficient for proper ignition. Keep your propane levels above this threshold, especially when temperatures drop. Cold weather makes this problem even worse.

Chewed Wires and Sensor Problems

Small critters love to chew on pool equipment wiring. We see this constantly in Arizona – pack rats, mice, and other rodents treat sensor wires like their personal chew toys.

Check all visible wiring for bite marks or damaged sections. Pay special attention to areas near ground level or where rodents might nest. Sensor open/short errors often trace back to this exact problem.

EPROM Failures: When the Brain Goes Bad

EPROM faults show up as erratic display behavior or complete system freezes. This isn't something you can reset with a power cycle – the internal memory has failed and needs professional replacement.

These internal board failures require specialized diagnosis. Throughout Arizona, Shasta Pools Supply handles these complex electrical issues at our Phoenix, Mesa, and Surprise locations. Some problems simply need expert hands to resolve properly.

Want to learn more about Raypak heaters and how they compare to the competition. Checkout our relevant pool heater articles. 

1. How to Calculate the Perfect BTU
2. 8 Best Pool Heaters
3. Raypak Pool Heater vs Hayward

Understanding Raypak error codes doesn’t have to feel overwhelming. Once you know what each message means — BD1 for board failure, PRS for low water pressure, HL1 for overheating, and others — you can quickly tell the difference between a simple reset and a problem that needs professional attention. These codes are your heater’s built-in safety system, and learning to read them helps you protect your equipment, your home, and your peace of mind.

Many errors come down to the basics: water flow, temperature regulation, ignition, or sensor readings. Some can be handled with a quick check or adjustment. But when you’re dealing with persistent shutdowns, electrical failures, gas valve issues, or flame rollout warnings, guessing isn’t worth the risk. That’s where expert support makes all the difference.

At Shasta Pool Supply, our team helps Arizona pool owners keep their heaters running safely and efficiently year-round. We stock a full range of Raypak heaters and genuine replacement parts — and if you need something specific, chances are we already have it on the shelf. You can pick it up at one of our Phoenix Valley locations, or have it shipped straight to your door. We offer fast nationwide shipping, so whether you’re local or across the country, you can get the right Raypak part quickly and confidently.

With the right maintenance and expert guidance, your Raypak heater can deliver years of reliable performance. And now, when an error code pops up, you’ll know exactly what it means — and where to turn for the support you need.

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