Hayward H350hdn heater overheating and tripping exhaust limit switch

[Red Arrow Pool]

Long story....Heater ran fine for a season with variable speed pump at 52%. Lo error would be easily remedied by backwashing filter. Then backwashing didn't fix it. Turns out the heat exchanger copper tubes were packed with calcium. I drilled them out with a hammer drill and concrete bit. Heater ran fine for a few weeks at pump at 50%. Then, the Lo error again. Turns out this time it was caused by the heater overheating thus tripping the exhaust limit switch. Then, I took out and inspected all of the burners. Had to empty about a half cup of ash out of each once, but other than that they seemed fine. I also vacuumed out all the soot and blew out the heat exchanger. Thinking this may fix it, I replaced the exhaust limit switch and it ran fine....except it overheated and tripped the switch again. I inspected the inside of the exchanger tube's again and they are perfectly clean. I think it's a flow problem, but for the life of me can't figure out why. Exchanger seems fine but maybe it's bad? Please help!

 

[PoolStored]

Hey! Spent many of my summers in Stevensville...one of the few here (I think) that would recognize the Red Arrow reference immediately...

Seems like you are taking the right steps...The following would help us...

Can you:
1) post some pictures of your pad so we can see the setup.
2) fill out your signature with the makes/models of all your equipment.

Create Your Signature - Further Reading

www.troublefreepool.com

3) you indicated that it was a couple weeks of working ok at 50%, then low error again. Low flow can be ALGAE related, even if you can't see it...

a) how are you testing your water?​

b) how are you chlorinating?​

c) what is your clean filter pressure with pump at high speed (3000rpm)? What is your clean filter pressure now at high speed (3000RPM)?​

d) can you post a full set of test results? FC, CC, pH, TA, CH, CYA...and SALT if you have an SWG...​

4) If you can, do an OCLT tonight and post results...Link-->Overnight Chlorine Loss Test

Imma guess that you might have algae...causing a reduction in flow because the filter is clogging...

Do/post as above and we'll see where we get to...

 

[ajw22]

Hayward H-Series Heaters - Further Reading

www.troublefreepool.com

A Hayward LO code is a limit string open error that occurs when any of the safety circuits on your Hayward pool heater opens. This forces the heater to shut down to protect your heater from damage.

Usual reason for the LO code is lack of sufficient flow not closing the Water Pressure Switch. Low water pressure can be due to a filter that needs to be cleaned, low pump RPM if a VS pump, open heater bypass valve, low skimmer water level, or even a stuck weir door.

Also on the Limit String is the Temperature Limit Switch, Exhaust Gas Temperature Limit Switch, and Vent Pressure Switch.

See pages 40-43 in the Universal H-Series Diagnostics Guide.

 

[Red Arrow Pool]

Hey! Spent many of my summers in Stevensville...one of the few here (I think) that would recognize the Red Arrow reference immediately...

Seems like you are taking the right steps...The following would help us...

Can you:
1) post some pictures of your pad so we can see the setup.
2) fill out your signature with the makes/models of all your equipment.

Create Your Signature - Further Reading

www.troublefreepool.com

3) you indicated that it was a couple weeks of working ok at 50%, then low error again. Low flow can be ALGAE related, even if you can't see it...

a) how are you testing your water?​

b) how are you chlorinating?​

c) what is your clean filter pressure with pump at high speed (3000rpm)? What is your clean filter pressure now at high speed (3000RPM)?​

d) can you post a full set of test results? FC, CC, pH, TA, CH, CYA...and SALT if you have an SWG...​

4) If you can, do an OCLT tonight and post results...Link-->Overnight Chlorine Loss Test

Imma guess that you might have algae...causing a reduction in flow because the filter is clogging...

Do/post as above and we'll see where we get to...

Thank-you for the reply. Here are some pics after I tore into it this morning.

Hey! Spent many of my summers in Stevensville...one of the few here (I think) that would recognize the Red Arrow reference immediately...

Seems like you are taking the right steps...The following would help us...

Can you:
1) post some pictures of your pad so we can see the setup.
2) fill out your signature with the makes/models of all your equipment.

Create Your Signature - Further Reading

www.troublefreepool.com

3) you indicated that it was a couple weeks of working ok at 50%, then low error again. Low flow can be ALGAE related, even if you can't see it...

a) how are you testing your water?​

b) how are you chlorinating?​

c) what is your clean filter pressure with pump at high speed (3000rpm)? What is your clean filter pressure now at high speed (3000RPM)?​

d) can you post a full set of test results? FC, CC, pH, TA, CH, CYA...and SALT if you have an SWG...​

4) If you can, do an OCLT tonight and post results...Link-->Overnight Chlorine Loss Test

Imma guess that you might have algae...causing a reduction in flow because the filter is clogging...

Do/post as above and we'll see where we get to...

Thank you for the quick response. And I kinda know Ashtabula area as we have non Amish friends that live in Middlefield! Here are some pictures after i tore into it this morning.

 

[ajw22]

Please post pictures to the forum...

Picture Posting and Resizing - Further Reading

www.troublefreepool.com

 

[Red Arrow Pool]

Please post pictures to the forum...

Picture Posting and Resizing - Further Reading

www.troublefreepool.com

Done.

 

[Red Arrow Pool]

Hey! Spent many of my summers in Stevensville...one of the few here (I think) that would recognize the Red Arrow reference immediately...

Seems like you are taking the right steps...The following would help us...

Can you:
1) post some pictures of your pad so we can see the setup.
2) fill out your signature with the makes/models of all your equipment.

Create Your Signature - Further Reading

www.troublefreepool.com

3) you indicated that it was a couple weeks of working ok at 50%, then low error again. Low flow can be ALGAE related, even if you can't see it...

a) how are you testing your water?​

b) how are you chlorinating?​

c) what is your clean filter pressure with pump at high speed (3000rpm)? What is your clean filter pressure now at high speed (3000RPM)?​

d) can you post a full set of test results? FC, CC, pH, TA, CH, CYA...and SALT if you have an SWG...​

4) If you can, do an OCLT tonight and post results...Link-->Overnight Chlorine Loss Test

Imma guess that you might have algae...causing a reduction in flow because the filter is clogging...

Do/post as above and we'll see where we get to...

I think I did all you told me to do with the signature,.etc. I'm pretty sure it's not algae as return flow is plenty. Upon more research, it appeared I've had the pump.speed too low which affected the fins of the exchanger?

 

[Red Arrow Pool]

Ordered a new exchanger today.