Pool heater destroyed

[pwave]

Hi everyone,
Thanks to all for contributing to this tremendous resource.

I am a relatively new pool owner. This is the third season I am using my pool. The pool was built in 2014 along with all its equipment, including a Raypak 400,000 BTU gas heater. It is a salt water pool with a SWG. I have kept the chemistry and balance decently for at least the time I have owned it (2 years).
The first summer the heater was fine. In the middle of last summer, the heater would not ignite and would give a pilot not sensed error. I figured it was just the pilot assembly. I had a gas contractor look at it and upon opening it, the insides were all corroded, rusted and destroyed, essentially falling apart. See photo.
During COVID, pool heaters are in demand, prices are 30-40% higher and they don’t even know if this heater will come in weeks-months even if I order it now. It would cost me about 5K (Canadian) to replace this heater... to be honest I’m in no rush and am going to try a solar blanket this season as we use the pool when it’s hot out anyway.

my question is... has anybody seen this degree of damage for a pretty expensive heater after only 5-6 years of use? The gas contractor says there may have been a leak inside. There’s apparently a newer model (copper nickel) that is recommended for salt water pools specifically. They also said the heating supplier said I have to run my pool pump 24/7 to prevent this from happening again, saying for salt water pools this is necessary. I have never heard of this... obviously this is less than ideal.

can anyone help/comment on this situation?

many thanks in advance!

 

[mknauss]

Welcome to the forum!
That heater had very low pH water run through it for quite some time. Salt is not corrosive at the levels used in pools. Low ph is very corrosive. Adding acid directly to the skimmer can also exacerbate the issue.
You do not need the cupro-nickel exchanger for salt. If you have pH issues, you might need it for that. Typically that comes from trichlor use.

I suggest you read ABC's of Pool Water Chemistry.

 

[mknauss]

The picture you show is the fire tubes, not where pool water contacts.

 

[pwave]

Thank you very much for your reply. Yes I have read about chemistry and at least for the 2 years I’ve had it, the pH has not been acidic. In fact I have difficulty getting the pH down if anything- usually runs 7.7-7.8. I know that the previous owner used to use chlorine pucks directly in the skimmer which I do not do. I exclusively use the SWG and in fact bought a new cell and usually run FC between 1.5-3. I don’t use exogenous chlorine other than to shock the pool when opening, and if use pucks I use it in a floater in the middle of the pool never in the skimmer and I do that only to increase stabilizer levels if I need to.

 

[mknauss]

I know that the previous owner used to use chlorine pucks directly in the skimmer which I do not do.

There is the culprit. Very acidic water going directly to the heater.

 

[pwave]

There is the culprit. Very acidic water going directly to the heater.

Wow that is crazy! Could you comment on whether it is worth it to get the cupro-nickel to be safe when I get a heater eventually? Also- have you ever heard of running the pump 24/7 for a SWG pool? To me that seems insane?

 

[mknauss]

Cupro-nickel is unnecessary for a SWCG pool.. Again, low pH is what destroys heaters. The use of trichlor creates low pH pools.

Pump run time is determined by how long you need to run the SWCG to create the chlorine needed each day. The next reason is to skim the surface. So you have to learn your pools needs and determine how long to run the pump.

Please fill out your signature so we can give more detailed answers.

 

[JamesW]

Is the heat exchanger leaking at all?

Was the heat exchanger ever replaced?

Do you have a picture of the heater label?

Either a leak caused everything to be wet or chemicals like acid or tabs were stored in close proximity to the heater.

 

[pwave]

Thanks for all of your help everyone.

mknaus - updated my signature. SWG is Zodiac Duoclear 200 (with a 130 cell- this was not an option). Also, I understand run times with SWG in general. I was just asking about the advice given by the gas contractor that SWG pools need to be run 24/7 to prevent the chemicals from “sitting” in the heater- I found that advice very unusual. I’ve never heard of this.

JamesW- this is the only picture I took. I’m not sure if it’s the heat exchanger. I can ask the gas contractor. I am not aware of the heat exchanger being replaced before. The heater is a Raypak406A

 

[mknauss]

I was just asking about the advice given by the gas contractor that SWG pools need to be run 24/7 to prevent the chemicals from “sitting” in the heater- I found that advice very unusual. I’ve never heard of this.

That’s a new one. Mine sit in my heater all the time. That person is not to be believed.

 

[JamesW]

I was just asking about the advice given by the gas contractor that SWG pools need to be run 24/7 to prevent the chemicals from “sitting” in the heater-

If you have a tab feeder, then the pump should be on.

If the pump is off with tabs in the feeder, the chlorine from the feeder will migrate from the feeder and into the system and destroy everything.

 

[sktn77a]

If the previous owner put trichlor pucks in the skimmer then you probably don't have an automatic feeder. You can add one pretty easily (not recommended on this site - if you go this route, add a check valve after the heater and before the feeder) or just use liquid chlorine once a week - may need a little more frequently in the three weeks of summer (I lived in Rochester, NY for many years)!

 

[mguzzy]

If the heat exchange is still usable or even it if isn't would it be possible to replace the internals of the heater and not the whole box? Just curious. or if that is even worth it.

 

[superuser]

The damage in that photo has very little, if not zero to do with your pool chemistry.

There's a few things that come to mind about that would eat up a burner assembly like that:
- external water flooding the bottom of the heater
- chemicals stored nearby
- short run cycles of the heater (can't evaporate/drain the moisture and acidic compounds created curing combustion)
- incorrect burner adjustment (higher concentration of acidic combustion byproducts)
- clogged condensate drain

 

[swamprat69]

Hard to say without seeing whether the fire side of the heat exchanger is at all sooted... but can also be due to lack of cleaning/maintenance causing poor combustion and trapping heat/water vapor in the combustion chamber.