Arcoaire RPJ furnace problem, need advice

[Who Me?]

I have an Arcoaire RPJ heat-exchanger that I just recently had serviced for cleaning. The inspector cleaned the unit, but noticed that the fan comes on unusually late (around 2 minutes). He told me that the normal time is around 30 seconds, but that the temperature probe did not kick the fan on until 2 minutes. After the fan kicks on, the heat exchanger temperature continues to rise until it reaches a threshold point to turn off the burners (a safety measure). This happens rather quickly.

He thought that this might be an indication of bad circulation, so we opened any closed vents, and removed the filter to get the maximum airflow. Still, the heat threshold was reached. We then turned on the fan on the thermostat (this is the maximum fan setting). This allowed more air to flow through the exchanger, but the temperature within the heat exchanger was increasing, albeit slowly.

The inspector thought that the problem could be one of 2 things:

a) The heat ducts are undersized. or b) the furnace is too big for my unit.

I was describing my situation with some friends at lunch, who thought I should get another opinion on the matter. I will contact another furnance repair place shortly.

Does anyone here have an indication as to what the problem could be?

[Tekkie®]

Who Me? posted for all of us... I don't top post - see either inline or at bottom.

Certainly

[..p.jm]

DOn't x-post this shit to alt.hvac.

Click here every day to feed an animal that needs you today !!!

Paul ( pjm @ pobox . com ) - remove spaces to email me 'Some days, it's just not worth chewing through the restraints.' 'With sufficient thrust, pigs fly just fine.' HVAC/R program for Palm PDA's Free demo now available online

[Dr. Hardcrab]

I don't why, but I get a chuckle everytime I see this, Paul.

First you say "Don't do this shit!"

and then

"Oh! By the way! Help some cute little bunnies and kittens that are hungry!!!"

Kind of like going up to someone, kicking them in the nuts, and SINCERELY smiling and saying "Have a nice day!!!"

;-]

[TURTLE]

This is turtle.

Now that was not nice to kick Paul's Pussey like that !

TURTLE

[udarrell]

If it does not have an adjustable fan and limit switch (maximum limit too, of course), I would install one. (?) If you can see the temp climbing it probably has an adjustable fan and limit switch. (?) What temperature is the limit switch set at? (If limit is adjustable, it may also be set too low.)

The fan coming on late is not causing the temp to continue to climb and trip the limit. Reset it, if possible, to come on at a lower temp. If you set the kick-on too low, and the kick-off not low enough, the blower will short-run-recycle several times.

It appears there is not enough CFM airflow. This could be caused by a number of things: if it has one, a lint blocked evaporator coil. lint clogged blower wheel blades, bad blower motor or run cap if PSC motor, poor ductwork design, etc. Correct any, and/or all of these problems first, and then make the proper fan and limit control adjustments.

udarrell - Darrell

[m Ransley]

Gees, get a heat pro, one that knows that equipment, mine comes on after apx 1.5 minutes and it is working normal for my unit.

[..p.jm]

You see a disparity there ? :-)

Click here every day to feed an animal that needs you today !!!

Paul ( pjm @ pobox . com ) - remove spaces to email me 'Some days, it's just not worth chewing through the restraints.' 'With sufficient thrust, pigs fly just fine.' HVAC/R program for Palm PDA's Free demo now available online

[Carolina Breeze HVAC]

So...he didnt bother to check the fire rate obviously...

[Cooltemp Industries]

"TURTLE" wrote

Turd-le starts trouble once again.

[TURTLE]

This is Turtle.

I correct a poster to not talk bad about Paul's pusseys and you call me a trouble maker !

TURTLE