roll-out tripping!

[frustraded tech]

the "saga" continues, received the secondary yesterday, so we proceeded to change it today when I pulled it out I found 2 rings from the clam shell of the primary and proceeded to pull that out and visually inspected found a total of 6 rings busted out, so the primary will have to be replaced. Then I needed to make sure the secondary is in fact cracked or leaking and the only thing I could think of doing was to stand it with the bends towards the bottom and fill the tubes with water and let it sit for a while and had no water leakeage at all now the dillema is where was the water coming from? and obviusly why wasn't my combustion analizer registering CO in the conditioned air dam thing is brand new and for $2K you'd think it be calibrated..........

[chuckcrj]

the "saga" continues, received the secondary yesterday, so we proceeded to change it today when I pulled it out I found 2 rings from the clam shell of the primary and proceeded to pull that out and visually inspected found a total of 6 rings busted out, so the primary will have to be replaced. Then I needed to make sure the secondary is in fact cracked or leaking and the only thing I could think of doing was to stand it with the bends towards the bottom and fill the tubes with water and let it sit for a while and had no water leakeage at all now the dillema is where was the water coming from? and obviusly why wasn't my combustion analizer registering CO in the conditioned air dam thing is brand new and for $2K you'd think it be calibrated..........

An analyzer will not pick up CO in the supply air when the heat exchanger is cracked. There is nothing wrong with the analyzer, don't bother testing the supply air for CO, it doesn't tell you anything about how safe the furnace is.

[philjafo]

6 busted rings and it wasn't noticed on the first visit, this is why when I go to a new customer they get upset when I find stuff like that and they say it gets checked every year. Thank you for all the loyal customers they're the ones that don't get estimates from other companies and they stay with us forever.

[frustraded tech]

it always did in the past same analizer model, has a screen for flue and conditioned air. selection for gas type etc...

[frustraded tech]

it's not like i didn't test for it, that has been my diagnosis from the begining but I frustrated because could not prove or document it!

[Coolingfolks]

Just a thought...I have seen faulty roll out switches. I had a 90plus furnace kick my butt for a week, changed the switch and never had another issue with it. Luckily it was a friends system.

[littlebigdad]

Try measuring the temps at the roll out It shouldnt be even close to the trip temp

[hvacmontana]

Roll out switch tripping on the H9mpd series furnaces is usually the result of a problem with the secondary heat exchanger. There was a problem with the oil used when the heat exchanger was formed. It would react with acid from the flue gases and form a thick sludge that pluged the tubes in the exchanger. It required removal of the cold header box and the turbulators and then working a wire with a rag attached thru each tube till they were clear. A messy and time consuming job but it would get the furnace working. Worse case would be a cracked secondary heat exchanger although I have not found one yet.

[frustraded tech]

we found 6 rings busted out, plus first post explained that we switched the roll-outs and the unit kept tripping on the same spot not the switch.

[frustraded tech]

upon inspection this exchanger was very clean small buildup @ the bottom where the transfer box to the secondary bolts on.

[frustraded tech]

this particular unit did not have any sludge what so ever!

[Jesjen829]

the "saga" continues, received the secondary yesterday, so we proceeded to change it today when I pulled it out I found 2 rings from the clam shell of the primary and proceeded to pull that out and visually inspected found a total of 6 rings busted out, so the primary will have to be replaced. Then I needed to make sure the secondary is in fact cracked or leaking and the only thing I could think of doing was to stand it with the bends towards the bottom and fill the tubes with water and let it sit for a while and had no water leakeage at all now the dillema is where was the water coming from? and obviusly why wasn't my combustion analizer registering CO in the conditioned air dam thing is brand new and for $2K you'd think it be calibrated..........

Just cause you have a crack doesn't mean co in condition space

[Juan Madera]

CO rots steel! Any CO. If you have pulled a water heater burner covered with flakes of rust, you have seen CO at work. I concur with the flakes in the secondary. ALSO; you mentioned the Delta T being high. Perhaps a restricted duct? What is the External static on the system?

sorry, forgot to mention that has been done the flue readings where about 89% efficiency 122F & 6.2 CO