New gas pool heater full of scale

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creechy

0
Oct 14, 2009
125
We have a gas pool heater that is less than 2 years old. We started having trouble with it knocking. 1000 dollars later it is working. The first issue that was identified was that the plumbing was wrong. The water was going in the heater at the out port and out of the heater from the in port. The pool installer came and fixed this issue. The heater continued to knock. So then the bypass spring was replaced as well as the thermostat. Still knocking. Last they ordered a kit to clean everything and replace some of the rings, etc.. The heater repair man cleaned out lots of scale. Now my heater works!

Why would I have so much scale in less than 2 years (we use the pool year-round)? Could it be the plumbing reversed? Could it be that I have hard water? What can I do to prevent this from happening again?

Thanks for your help!
 
Thanks!

FC 4.5
CC 0
Ph 7.5
TA 70
CH. 220
CYA 40 ( I am always uncertain with this. I second guess myself about the block dot disappearing.)

Another problem for me is CH. It usually goes purple befor it turns blue and it is hard for me to find that exact change.

Thanks for your help!

Dory
 
There is nothing about your current water numbers that suggests any chance of scaling problems, which leaves a bit of a mystery. Your water chemistry could have been worse in the past, and the scaling could have happened then, but then there wouldn't be any reason for the knocking to have started recently. Another possibility is that your CH level is actually much higher than you think it is, though that seems unlikely.

The water inside the heater is hotter than the water in the pool, and hotter water is more likely to cause scaling, but even so your CH level would have had to have been over 400 at some point to have any significant chance of scaling.

Having the CH test turn purple is called a floating end point and can cause invalid test results. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total.
 
You would need to look at a historical data plot to determine if water chemistry may have caused the scale formation, rather than a snapshot.
If your calcium hardness, total alkalinity, or pH were kept on the higher side are any duration of time, that would haave caused scale to build up. You wouldn't happen to have your past years test results would you?
 
I am not being particularly helpful, but I'm fairly certain I remember that "knocking" in a hot water heater is a direct indicator of scale. I do not have experience with a pool heater but the idea is the same.
 
duraleigh said:
I am not being particularly helpful, but I'm fairly certain I remember that "knocking" in a hot water heater is a direct indicator of scale. I do not have experience with a pool heater but the idea is the same.
Click to expand...

The knocking is indicator of low flow. The low flow could be because of scale, or low flow.

Reversing the inlet/outlet ports can cause scaling on Raypak/Rheem, and Pentair/ Sta-rite heaters.
 
Thank you so much for all the replies! Now that I have my Taylor K2006 test kit, I am getting more accurate results. The kit includes a wheel for calculating the SI. For the first year, I used test strips and pool store results. Thanks to the advice from this forum, I am doing better. Hopefully, my heater problems are over!
 

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