Problems with newer Reznor Unit Heater

[hvacdoctor]

Installed a seperated combustion unit heater Model #UDAS150 Used a Reznor supplied concentric vent kit and installed per Reznor instructions. Got called out a year later that tje flue pipes were rusted and dripping water everywhere. Checked it, called my vendor rep and Reznor local reps in to verify the problem.

Reznor rep said we have to retro fit the flue pipe to b-vent and had a instruction bulletin from Reznor. GREAT they admit the problem!

Customer does not want to pay for correction work and now thinks we sold them "Lemons". We corrected the flue vents per instructions in Fall. Now, one unit is leaking water from the flue motor cabinet where it attached over the burner outlet side. The condensate has rusted out the metal to a big patch of rust and inducer motor grommets are dry rotted. Unit looks like its 20 years old now. Reps now want water and scale samples... I never ever had this much trouble with a Reznor product before!

[Drewmich]

Doc - we have a very similar problem in a newer warehouse we built in 2005. 15,000 sq ft - dry warehouse - (4) UDAP-150s NG. They were installed correctly and last fall all (4) were inspected and had major heat exchanger damage - splits/cracks and rust holes. Reznor shipped us replacement exchangers but today - when starting the retrofit process - lowered the first UDAP and dissembled it and it was full of rust and corrosion. What did Reznor do with yours and what do you recommend?

I email a lengthy description to their warranty dept and I am guessing they will contact me this week as we are entering our heating season and I am very concerned about operating them until they are repaired.

Andy Roach
Mandaker Development

[250]

hi
What was your temperature rise, and what is your maximum temperature rise?
250

[hvacdoctor]

Doc - we have a very similar problem in a newer warehouse we built in 2005. 15,000 sq ft - dry warehouse - (4) UDAP-150s NG. They were installed correctly and last fall all (4) were inspected and had major heat exchanger damage - splits/cracks and rust holes. Reznor shipped us replacement exchangers but today - when starting the retrofit process - lowered the first UDAP and dissembled it and it was full of rust and corrosion. What did Reznor do with yours and what do you recommend?

I email a lengthy description to their warranty dept and I am guessing they will contact me this week as we are entering our heating season and I am very concerned about operating them until they are repaired.

Andy Roach
Mandaker Development

If I recall after visit afer visit they decide to give me a new heater but no labor credit for any of the service calls or the install. Good luck and I would let the factory know about it.

[hvacdoctor]

hi
What was your temperature rise, and what is your maximum temperature rise?
250

Can't really check that if the unit is in operable and rusted out. The problem is you can check it the hour your in there but when you leave the customer can change and run the units any way possible. I always tell people they must be set at 55F or above to work and last. Most dont listen but the manufacturer must include this factor in the design of the equipment.

[kevinnn]

Sounds like the problem is the concentric single wall. Exhaust pipe cooled down to fast with inlet around it causing the moisture in the gas to condense. Basically they turned into condensing furnaces. Hopefully they will provide B vent and a labor allowance.. etc..etc.. Because that shouldn't be falling on you.

[hvacdoctor]

Sounds like the problem is the concentric single wall. Exhaust pipe cooled down to fast with inlet around it causing the moisture in the gas to condense. Basically they turned into condensing furnaces. Hopefully they will provide B vent and a labor allowance.. etc..etc.. Because that shouldn't be falling on you.

I dont think they will do offer a credit because way back then there was tech bulletin out.

Yes that is the issue single wall pipe and below dew point issues.

[deux]

Our local code here never allowed the concentric vent. We always had to use B vent. Now we have local code bulletins asking us to use stainless for venting in place of B vent. The B vent rots out as well. Right at the wall where it exits. Maybe you should see about getting permision to go straight to stainless. Skip the B vent experiment.

They also love to get ice in the metal pressure tap to the switch.