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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Trying to find a manual for a Rudd URKA A048JK08Xcombo unit.

Customer Question

Trying to find a manual for a Rudd URKA A048JK08Xcombo unit. Unit tripped breaker and now won't restart . Fan won't even kick on
JA: Did you double-check the thermostat? And what about the unit's filters?
Customer: Yes, checked thermostat, and filters replaced 2 weeks ago
JA: Do you plan on doing the work yourself?
Customer: Trying to hit basic stuff myself before calling service tech
JA: Anything else we should know to help you best?
Customer: Nope
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset. I am HVAC Guru an extremely experienced tech on the site and I try to get to as many customers as I can. I just picked up your question now. NOTE it takes time for me to type research and add links so please wait for me to respond back I can only do this so fast. Secondly I am not paid anything until you rate my service good using the STAR RATING LINK at the top of your page, the money is paid to the site not me directly.


What likely happened is the low voltage fuse in the furnace or airhandler blew. There typically is a SLOT STYLE 3-5AMP FUSE on the board itself inside the furnace/airhandler like this.


If that is burned out all power to the thermostat will be lost. 95% of all units use some sort of SLOT FUSE or inline BUS STYLE FUSE to protect the low voltage circuit. You need to find that and change it out. If you just bump two wires together you could have just popped it without even knowing it. Now if for some reason your unit does not use a fuse often the board will be damaged due to the short. You would need to confirm you have 24 volts to the board inside the furnace/airhandler with a volt meter to make sure though.

Note if you have a condensate pump check the float and make sure the pump is not full of that could cut low voltage power to the unit as well if the pump is not working and full of water.

All I ask is please use the Star Rating Link at the top of your page before leaving, that is the only way I am paid anything through the site and that will also get you a DIRECT LINK emailed to you to get back to me! are greatly appreciated so thank you very much for using this service. If you have any other questions just post back to me here anytime!

Customer: replied 1 year ago.
Great, that is useful and informative, but it doesn't tell me or show me where to find the board on my particular unit. I took off three of the side panels looking for the board to check any internal fusing but did not find any thing like that. What I need is either a manual for my particular unit, a picture of my unit telling me where to look, Or a better description of where to find it. It is quite likely you have correctly identified the problem, but at the moment that falls into true but useless info, until I can locate the board or fuse. I am a PHD physicist who repairs arcade games and pinball machines as a hobby, so I know what I am looking for, but in this case, there are no obvious spots to look beyond what I did look at already
Expert:  HVAC Guru replied 1 year ago.

Did you check for power to the unit with a volt meter?

Customer: replied 1 year ago.
I would if I could find a place to check it. I see where the 230v comes in, but I do not see where it connects internally, no wire connections, no controller board. This is my challenge. I have removed three of the side panels, examined inside, and the only connector I find is to the blower motor. Both motors and fans spin freely.But no obvious points to measure a voltage, or find a fuse. Hence my original question of a manual, or my initial response to you of needing to know where to find the board or fuse. I checked the breaker, and the breaker is good, and I have 230v out of the breaker leading to the AC unit.
Expert:  HVAC Guru replied 1 year ago.

Can you take a picture of the board and upload it here?

Customer: replied 1 year ago.
That is my problem, there is no board visible.after dinner I can go back up on the roof, and examine it again, and upload pics.
Expert:  HVAC Guru replied 1 year ago.