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-   -   Comfortmaster RPJ II Open High Limit (http://www.diychatroom.com/f17/comfortmaster-rpj-ii-open-high-limit-36671/)

khalidmo81 01-23-2009 10:05 PM

Comfortmaster RPJ II Open High Limit
 
Hello...Hopefully someone can guide me here. I have a Comfortmaster RPJ II, I am getting 4 flashing red lights. The diagram on the furnace indicates an open high limit switch. I replaced the filter and I have the same issue. the furnace will run fine without the filter installed. I removed the blower and cleaned it out there was a lot of dirt on the fins of the blower. I removed what I think is the limit switch and wiped off its surface. I checked all of the vents and made sure they were all open and none of the return vents are blocked. Needless to say still the same issue. Any ideas??? Thanks in advance.

I forgot to mention it is a downflow furnace and the limit switch I checked is the upper one. Checking the lower one now...

khalidmo81 01-24-2009 05:53 PM

Reading through previous posts I understand now that cause could be an air flow problem. I was reading elsewhere that the AC coils may be dirty and require to be cleaned. Being that it is a down flow furnace and the AC coils sit on the bottom, if I remove the coils for cleaning could the furnace fall or should it be supported somehow?

Dr Heat 01-24-2009 11:33 PM

depending on how the coil was installed you may need to pull the furnace to clean it.

Now if the coil is in a factory supplied cabinet or the installer made it accessible you may be able to remove the front and clean it.

You should be able to get your hand in without pulling the coil.
If you do need to pull the coil do not kink the copper lines.

This should be a DYI but be gentle you could easily bend the coil fins or kink a line and all your savings are gone.

khalidmo81 01-25-2009 10:30 PM

THANKS! I will try it tomorrow evening. It looks like the installer did leave an access panel at the bottom of the furnace.

One more questions, at my dads house there is a vent that has a handle labeled summer and winter, like some kind of damper, is this supposed to be available on all HVAC systems?

khalidmo81 01-28-2009 04:22 PM

I was able to remove the front cover off and clean the coils. Wow they were caked with dirt. I popped the filter in and sat in front of the unit for 30 minutes...it works like new again. The airflow coming from the ducts is a lot better. Can't wait for summer clean the exterior condenser and start the AC.

Thanks Dr Heat for your advice.

biggles 01-28-2009 04:32 PM

filter...squirrel...coil is how that dirt travels at least your good for the winter.plan on doing a liquid wash on that evaporator for the summer to get the dirt between those coils out.

JohnH1 01-28-2009 04:37 PM

Quote:

Originally Posted by khalidmo81 (Post 219192)
THANKS! I will try it tomorrow evening. It looks like the installer did leave an access panel at the bottom of the furnace.

One more questions, at my dads house there is a vent that has a handle labeled summer and winter, like some kind of damper, is this supposed to be available on all HVAC systems?

This handle is probly on the humidifier. Open in winter and closed in the summer. But not all humidifiers have them. and not all furnaces have humidifiers.

khalidmo81 01-28-2009 04:43 PM

I bought the house 2.5 years ago, this is my third winter there. When I moved in the previous had the wrong size filter in the unit, it was 2 inches to small and to top that off - it was the cheap 30 day kind (probably has not been changed for 6 months), the humidifier filter was never changed or cleaned, there was so much hardwater build-up on the filter and the inside of the humidifier that it leaked out of the unit onto the floor and damaged the walls.

All that to the side - any pointers on cleaning the condenser?

JohnH1 01-28-2009 04:47 PM

Turn off the power remove the top or whatever panal is neccessary to be able to wash it from the inside out. IE: the oppisite direction of airflow.


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