Raypak 156A Heater Corrosion - Only 3 years old

[brentvw]

Hi all,

Avid TFP follower here. 9,000 gallon vinyl SWG. Maintenance schedule is a cup or two of acid per week to maintain PH, never had algae, water always clear.

Was surprised to see our Raypak 156A gas pool heater not make it to see it's 4th season. We are in Michigan so it only runs about 4 months out of the year.

Heat exchanger corroded and leaked onto burners rusting out the burners and pilot. $1,000 worth of parts to replace alone.

Pool guy, heater repair co, and distributor all saying chemicals, that 99% of heat exchanger problems are almost always chemicals. Manufacturer says running at FC 5+ will corrode the exchanger and states this in the Raypak recommended levels.

Should I be running at different levels to help prolong the heater? Was this for sure due to chemicals? I want to get more mileage on the heater next time around, they are expensive.

FC 7
CC 0
pH 7.6
TA 70
CH 150
CYA 60
NA 3200

 

[ajw22]

What pump do you have?

Post a pic of your equipment setup.

Notice that the Raypak Water chemistry recommended levels make no mention of CYA. 5 ppm of chlorine with 0 CYA is very harsh. 5 ppm of FC with 30 ppm or more of CYA has less then 1 ppm of active chlorine. Read CYA - Further Reading

Note that the manual says:

An auxiliary bypass valve must be used when flow rates
exceed 70 GPM (265 LPM). Usually a high-performance
pump size larger than one horsepower will exceed this
flow rate.

 

[brentvw]

See attached. It is 1HP so flow rate < 70 GPM internal bypass should be sufficient.

It was interesting to call around and hear how long these last, some distributors said 10+ years, some said 5-7 years on average, some said they are built to leak.

 

[ajw22]

See attached. It is 1HP so flow rate < 70 GPM internal bypass should be sufficient.

That pic does not tell me the pump model number to see what the pump flow curve is. Some 1 HP pumps can flow more then 70 GPM depending on the impeller it has. Your plumbing has little head to slow the flow so you likely get close to maximum flow rate from the pump. A high flow rate will erode the inside of the heat exchnager over time.

 

[1poolman1]

An AGP pump is of a different design than one for an inground. For starters they are usually medium-head pumps. It is not likely that your Hayward Power Flo Matrix (an AGP pump) will move 70gpm through that sand filter. It appears to be an S-244T with a design flow rate of 44gpm. On an open line, maybe. A 1hp high-head pump designed for inground pools would have no problem moving 70gpm with the right size plumbing/filter, etc. They also cost considerably more than an AGP pump. Horsepower is just one rating of a pump's performance, basically just the amount of energy it will use.

If that damage was the result of copper erosion due to water velocity, even an AGP would have copper staining from the copper in the water. Chemical damage.

 

[brentvw]

Yes, should have mentioned AGP. Also had heater guy check gas flow with manometer, all good there.

So did I get just get a bogus heater that didn't last long? Should I keep up my same chemistry regimen and hope for better results next time?

I know Raypak are solid units based on research, my pool guy recommended a Pentair MasterTemp over Raypak but this seems to be more of a preference.

 

[1poolman1]

For that kind of damage it wouldn't have matter what brand of heater. For warranty purposes it is best to stick to RayPak's chemistry guidelines for the length of the warranty at least. It is different from the TFP method. However, RayPak (nor any other maunfacturer) will not honor a warranty against chemical damage if it hasn't met their data published in the owner's manual.

 

[brentvw]

For that kind of damage it wouldn't have matter what brand of heater. For warranty purposes it is best to stick to RayPak's chemistry guidelines for the length of the warranty at least. It is different from the TFP method. However, RayPak (nor any other maunfacturer) will not honor a warranty against chemical damage if it hasn't met their data published in the owner's manual.

Ok, thank you for the advice.