Raypak Pool Heater - still hanging on…

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ImMyOwnPoolGuy

New member
Sep 2, 2022
3
New Jersey
Posting this for someone who might find themselves in the same situation...

I’ve had my pool for about 8 years now and have been troubleshooting a lot of my problems myself this year, starting with replacing the salt cell, to replacing the Hayward Aquarite Goldline main board and most recently dealing with the Raypak heater smoking and producing a lot of soot. I had a pool service come by once at the start of the season when the heater wasn’t working at all after the same smoke and soot issue. They brushed the and hosed off the heat exchanger and replaced the thermal cutoff fuse. They charged me $50 for a part that‘s $12.00 on Amazon, but I needed to get my pool going and didn’t even know where to start. From what I’ve learned, these fuses are one time use and if the heater starts to have problems, this thing burns out to avoid the heater overheating. I’ve since bough a couple of spares to have on hand just in case.

Well, nothing makes you learn better than experience and necessity. There are a ton of videos on YouTube, so when the heater started acting up again, I decided to DIY it knowing that I very well might end up having to call in a pro. The RayPak heaters have a common problem with soot build up on the heat exchanger. After pulling the cover off, I could see the soot and carbon buildup on the heat exchanger and the horizontal bars were corroded and falling apart. I removed the bars (I don’t know what purpose these bars serve - can anyone tell me?) and used a wire brush to scrub the heat exchanger. I then used a garden hose to spray it down with some pressure. Same process with the bars. A TON of soot and Crud came out the bottom front of the unit. I know I should have removed the burner tray because the soot can clog the burners, but I didn’t want to go through the hassle of disconnecting the gas line and water in/out feeds to access it, as this was my first time working on a heater of any sort. And I don’t think the pool service I used the last time did that. I let it dry for a bit, replaced the thermal cutoff fuse and then put it all back together, fired it up and “click”… nothing. The heater normally makes a bzzt bzzt bzzt sound before lighting. Nope. Just one click.

Back onto YouTube and decide to clean or replace the igniter. After figuring out what’s what and how to remove the assembly, I scrub the fork and the contact with some sandpaper and brush the nozzle with an old toothbrush, reassemble and turn it on. Click, bzzt bzzt bzzzt (hey, it’s working!) but it doesn’t light and I get an error message saying the Pilot isn’t recognized. Turn it off and back on again to see if I get the same error, grab some coffee and sit down with my iPad to go back on YouTube. I look up and see heat ripples coming off the heater. Stick my hand in the pool jets and it’s coming out warm. Go to the heater and the display reads “heating”. Finally fixed. The real trick will be if the heater lights and kicks on with the pool timer tomorrow morning.

I don’t know how much longer this heater will last. From what I read 8-12 years is the average lifespan. We’ll see.
 
You probably don’t want to hose off the exchanger unless you remove it from the unit. You can cause the firewalls to prematurely deteriorate. Compressed air or lawn blower usually do the trick. I would pull your unitherm governor and make sure it’s opening enough and make sure gpm are adequate.
 
V-bars allow the flue gasses to stay in contact with the heat exchanger longer, increasing efficiency. Fusible link stops the heater if flame gets out of the firebox so as to not burn up the control area, including the gas valve.
 

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Bugman1401 said:
If this is a gas heater, how can you have soot without organics to burn? Are leaves getting into the chamber? Need pics.
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Incomplete combustion of natural gas (mostly methane) leaves a variety of carbon based chemical compounds including solid carbon and carbon monoxide that can comprise the soot.

Full combustion produces carbon dioxide and water vapor.

Incomplete combustion is dangerous due to the carbon monoxide produced.

A fully blue flame usually indicates complete combustion because it indicates the correct flame temperature.

A blue flame is much hotter than a red, yellow or orange flame.

Incomplete combustion results in a cooler flame because not all of the energy has been converted into heat.
 
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All these videos and none on an actual pool heater with sooting. Perhaps this occurs mostly with closed chambers. Don’t know if Raypac’s are closed, but I’ve never seen it on open box design unless some leaves/grass got into the chamber or some of the control wiring shorted out.
 
In the complete combustion of methane, the carbon atoms go from an oxidation state of -4 to an oxidation state of +4.

In incomplete combustion, the carbon atoms might go to an oxidation state of 0, which forms carbon soot.

Carbon can go to an oxidation state of +2 and form carbon monoxide.

Any interference in the amount of available oxygen can result in soot formation or carbon monoxide formation due to the incomplete oxidation of the carbon atom from -4 to +4.

Every carbon atom needs to lose 8 electrons, which requires enough oxygen to oxidize or take electrons from the carbon.


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Poolbreh said:
Does condensation have any impact on increasing the production of soot? Just curious why two of the causes in the manual are ug and reduce flow rates.
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Condensation creates water on the outside of the heat exchanger, which interferes with the flow of air through the heat exchanger.

It can also lead to chemical reactions that leave residues on the copper fins that interfere with the flow of air or exhaust.

The heater is designed to be as efficient as possible, which requires tight tolerances.

Any interference with the flow of the gasses of the exhaust can reduce the amount of oxygen available for combustion.

Even a tiny amount of interference can have a cumulative effect of creating reduced airflow, which creates more problems, which creates more soot etc.

The combustion of methane creates water vapor and there is water vapor in the air, so there will always be water in the exhaust.

The unitherm governor (Thermal Regulator) blocks the flow of water through the heat exchanger until the water is warmer, which helps reduce condensation.

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