Unbonded Pool

[MarkHoop]

I appreciate the feedback that I have been getting in the forums and have found them to be very useful .

I have been having HX corrosion issues since the installation of a new replacement heater in 2019 92 HX replacements)...another forum and another time...
I know that the manufacturer is claiming a few areas of concern

1. Poor Pool Chemistry
2. Lack of Check Valve between the Heater Outlet and the SWG
3. Lack of pool bonding

So for the sake of this forum lets simply focus on concern # 3.

The pool was installed at a time many years ago when bonding was not a code requirement and as such there is no bonding loop on the pool nor any of the equipment inside the pool house. I guess my questions would be:

1. Does the potential between pool equipment vary such that the original heater lasted 15 years however the new one has gone through 2 HX's in 5 years?
2. Is there a way to actually measure the potential of equipment to identify a bonding issue? Does the pool need to be running in order to do this? (The pool is now closed as it is almost November here in Ontario, Canada)
3. Is there a "better than nothing" retro-fit that I can do to make up in some way for the lack of bonding as I am not keen on ripping up the concrete deck around the pool.
   1. Bond all equipment within the pool house?
   2. Bond equipment to a sacrificial anode

A good friend of mine is a pool service tech and has indicated to me that he finds it hard to believe that bonding is the issue as over 95% of the pools he services are not bonded and all have heaters without issue....

Thanks in advance

 

[Bperry]

I appreciate the feedback that I have been getting in the forums and have found them to be very useful .

I have been having HX corrosion issues since the installation of a new replacement heater in 2019 92 HX replacements)...another forum and another time...
I know that the manufacturer is claiming a few areas of concern

1. Poor Pool Chemistry
2. Lack of Check Valve between the Heater Outlet and the SWG
3. Lack of pool bonding

So for the sake of this forum lets simply focus on concern # 3.

The pool was installed at a time many years ago when bonding was not a code requirement and as such there is no bonding loop on the pool nor any of the equipment inside the pool house. I guess my questions would be:

1. Does the potential between pool equipment vary such that the original heater lasted 15 years however the new one has gone through 2 HX's in 5 years?
2. Is there a way to actually measure the potential of equipment to identify a bonding issue? Does the pool need to be running in order to do this? (The pool is now closed as it is almost November here in Ontario, Canada)
3. Is there a "better than nothing" retro-fit that I can do to make up in some way for the lack of bonding as I am not keen on ripping up the concrete deck around the pool.
   1. Bond all equipment within the pool house?
   2. Bond equipment to a sacrificial anode

A good friend of mine is a pool service tech and has indicated to me that he finds it hard to believe that bonding is the issue as over 95% of the pools he services are not bonded and all have heaters without issue....

Thanks in advance

Bonding is the process of connecting various conductive objects around the pool so they all have the same electrical potential. The concrete deck, the rebar in the pool shell, ladders, handrails, etc. It’s not necessarily an indicator of having no bonding grid just because there’s no wire coming out of the ground at the pool house.

All you need to do to check the bonding is to measure the resistance between different items around the pool…usually the water and something else. If there’s zero resistance, there won’t be any potential difference. As a side ways of checking more, you can check for voltage between those different items as well. The voltage is probably a little easier to check since lots of stuff around the pool will have some kind of conductivity resistance between them.

But lack of bonding didn’t kill your heater.

 

[JamesW]

You might have a stray current in and around the property causing oxidation of the copper.

Stray currents can sometimes be easily located and sometimes the person never finds the source and just gives up and lives with it or sells the house and moves away to a place without stray currents.

 

[JamesW]

There is an almost unlimited number of potential causes of a stray current and each one is unique.

So, trying to find a stray current depends on the cause and the person really needs to know exactly what they are doing to find it.

Grounding ties things together, so the voltages tend to equalize out.

It is not as simple as some people think where you can just put a voltmeter here and there to check for voltage.

 

[MarkHoop]

Bonding is the process of connecting various conductive objects around the pool so they all have the same electrical potential. The concrete deck, the rebar in the pool shell, ladders, handrails, etc. It’s not necessarily an indicator of having no bonding grid just because there’s no wire coming out of the ground at the pool house.

All you need to do to check the bonding is to measure the resistance between different items around the pool…usually the water and something else. If there’s zero resistance, there won’t be any potential difference. As a side ways of checking more, you can check for voltage between those different items as well. The voltage is probably a little easier to check since lots of stuff around the pool will have some kind of conductivity resistance between them.

But lack of bonding didn’t kill your heater.

So it is my understanding from reading that a resistance between items of < 1 Ohm is considered to be reasonable. Sorry if I missed it but in order to do this measurement say for the heater (since that is the concern) do I simply measure from the bonding lug on the Heater to various other items (water, pump, SWCG etc)? I also need to "zero" my test wire by simply measuring the resistance over the length? And maybe a silly question but should the pool be running when I perform these tests?

 

[Bperry]

So it is my understanding from reading that a resistance between items of < 1 Ohm is considered to be reasonable. Sorry if I missed it but in order to do this measurement say for the heater (since that is the concern) do I simply measure from the bonding lug on the Heater to various other items (water, pump, SWCG etc)? I also need to "zero" my test wire by simply measuring the resistance over the length? And maybe a silly question but should the pool be running when I perform these tests?

It’s gonna depend on how much patience you have to find something that may not be there.

I’m assuming the warranty dept told you the pool wasn’t bonded as an excuse and they didn’t actually measure anything to confirm that a “lack of bonding” is what caused the HX to fail? Be warned that you may be trying to chase something that isn’t there and that’s hard to find.

If the only concern is the HX, then I’d measure between that and:
1. The heater chassis
2. Heater ground lug
3. Ground/dirt/cement supporting the heater
4. the pool water

All while the pool equipment is on and off. You don’t need to zero or calibrate anything. Just get a decent functioning meter and measure for AC or DC voltage between those items in a few different places.

But note that if you don’t find any voltages present, they still aren’t gonna change their mind and replace the heater.

 

[MarkHoop]

But note that if you don’t find any voltages present, they still aren’t gonna change their mind and replace the heater.

Thanks and at this point it is not about getting them to change their minds, although I will pull out all the stops there, but rather to understand or at least get a better handle on what the reasoning is for the early failures so that I am simply not throwing good money at bad....I am sure there is a definition in there somewhere....

 

[Bperry]

Thanks and at this point it is not about getting them to change their minds, although I will pull out all the stops there, but rather to understand or at least get a better handle on what the reasoning is for the early failures so that I am simply not throwing good money at bad....I am sure there is a definition in there somewhere....

Definitely try the check valve as well, though that shouldn’t make much difference.