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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Lennox conservator 90 GWB 100 with what we think is

Customer Question

Customer: ***** *****, I have a Lennox conservator 90 GWB 100 with what we think is a partially blocked heat exchanger. It cycles through proves the flame but shuts down after 15-30 seconds. Does not lock out but just keep cycling. Both repairman believe it's a blocked heat exchange. How hard is it to clean. I realize I would have to take apart.
JA: Thanks. Can you give me any more details about your issue?
Customer: fan runs half voltage which is one reason we believe it is a blocked exchange. flame looks good, burner was taken out and cleaned 2 years ago, drain tubes recently pluged and after I cleaned them the system will not stay running, just keeps cycling. checked pressure, flues, ect... water will only get to about 120
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Submitted: 1 year ago.
Category: HVAC
Expert:  Tim H. replied 1 year ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need.

Heat exchangers can be cleaned, but you have to ask your self "what caused it to soot up in the first place?". If it has a crack, then cleaning it is pointless, it must be replaced. However, if it was caused by rusted over burners, then yes, soot can be cleaned out. It's a messy job and involves disassembling unit, taking out burners, draft hood, etc. The the soot needs to brushed, cleaned out with a vacuum and reassembled.

Expert:  Tim H. replied 1 year ago.

Did you have additional questions on this?

Customer: replied 1 year ago.
Your answer is incorrect. I followed up with Lenox and the model does not have a heat exchanger that can be cleaned or replaced. It is a cast aluminum module that is all one piece with no heat exchanger. The whole thing needs to be replaced.
Expert:  Tim H. replied 1 year ago.

Of course Lennox will tell you it can't be cleaned because they want you to buy the part, replace it. Believe me, been in this business over 20 years!

Customer: replied 1 year ago.
It's warrentied for 15 years so we're going through the paperwork now to have it replaced. You can call them yourself and get the specs yourself to verify if you don't believe me.
Customer: replied 1 year ago.
Won't cost me anything more than the labor to replace, cost them a new boiler
Expert:  Tim H. replied 1 year ago.

Good luck.

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