Rheem heat pump issue

Hello,
Glad I found this place. I am a do it yourselfer and fix most anything but need a little help here and there in some areas im not too familiar with. Ok got an outside Rheem heat pump model RPKB-024JAZ. Was working fine and all of a sudden I have nothing at all... no heat, no AC, no fan, nothing. I seem to have power everywhere and also at the air handler. I did find a fuse in the air handler that had no continuity and replaced that but no change.

So I crossed over the red and white wires to bypass the thermostat and nothing. Outside at the unit you hear no noise at all, no clicking, humming, nothing. There is power to the circuit board and contact unit and SC, everywhere but nothing at all.. The unit for upstairs works fine as we have dual units , one for upstairs and one for downstairs. The upstairs unit has kicked out a few times with low pressure cut out I think as it has onboard diagnostics with flashing diodes with codes you can check and also reset it which always fixes it and gets it going again.

That unit is ok and working but the downstairs unit is the problem. I was hoping the bad fuse would get it going but nothing. At the other place I lived the starting capacitor went out and a fuse another time inside but it was an easy fix. Heard it humming trying to start so I figured the SC and it worked. Now with this other unit now it isn't doing anything. Like I said no noise, clicking, humming , no nothing. Thermostat appears to work even bypassed it with red and white wire crossing and nothing.

checked wire connections where TS meets air handler and all good contacts. Fuse replaced shows good now had 125 volts one side and 10 on the other and no continuity when first checked. Now it has 125 on both ends as it should. So what should I check next? SC looks good no bulging or discoloration or anything. Circuit board in this one doesn't have the two flashing diodes to check codes and reset. It has two prongs which says TEST but I don't know what to do with them if anything. Im open for suggestions. I been a mechanic for years and can repair most anything so get indepth as much as you want I can figure it out and test whatever probably with my multimeter. Nothing fancy but it can do a lot of tests. don't have the clamp to check draw or anything but most other features.

Help please... Ideas??

Thanks,
Nick

 

Welcome to the forum!! The best place to start is testing to ensure you have the proper voltage coming in to the condenser. The easiest way is to test as shown in the attached diagram. Set voltmeter to volts AC and test ACROSS the terminals, not to ground. If you don't have voltage at those points you will need to determine what the cause is starting at the electrical panel.

 

Thanks for your reply. Here is what I found...

L1-L2=240V
T1-T2=0V ... I have 125V per side but together nothing
Single wires on sides should be 24V I have nothing on either

No that sounds like its not getting the signal from the thermostat? I have continuity at the air handler where the red meets the white wire tied in after I turned the heat on when it should send the call down to it.. Got a connection there with continuity check. So whats that tell you? What should I check now?

Thanks for helping and running through these tests maybe we will get her going before its all said and done...

 

TWhen you tested T1 and T2 and the two 24V terminals at the contactor did you have the thermostat set to HEAT several degrees above room temperature? Also, you can check the low voltage wires coming out of the transformer in the air handler. The transformer R wire powers the thermostat to provide voltage to the other terminals.

 

Yes thermostat is on heat and set at 80 when in fact it is only 66 in the house. Just to have it up a ways. Ill go to the air handler and check those now. Have to run out to the store but when I get back ill check and see what I get. So am I just checking this R wire on the transformer and if so what reading should I get?

 

You will need to check ACROSS the low voltage side wires coming from the transformer. Use extreme caution as there are 240V going into the transformer. One of the low voltage wires is "hot" and provides 24V to the thermostat. The other wire is common and goes out to connect to one of the 24V terminals on the side of the contactor. Some air handlers have a control board and will have a 3A or 5A automotive blade type fuse that may have blown. Other air handlers have this fuse wired in the low voltage side with a fuse holder. This fuse is installed to protect the low voltage side and from frying the transformer.

 

On the left side I have blue, black and red wires. On the left are 2 yellow wires.
Blue wire goes to a wire cap so it isnt used. Black and Red wires each go to the back side of each large fuse. Between them I have nothing which is Red to Black on back of fuses. Either wire Red or Black to each yellow wire gives me 115. Yellow to Yellow is 0. Either Yellow to ground is 1.9. Either Red or Black to ground is 125. I do not see a board with a fuse nor do I see a fusible link anywhere. What do you think now?

 

The black and red wires should read 240V across them. Since you have no reading that means you either tripped the breaker for that circuit or blew a fuse depending on the type of electrical panel you have. You will need to go to the electrical panel and reset the breaker or replace the fuse. Do you have a disconnect near the air handler? If so, you can start by checking voltage there.

 

Something odd is going on here... All four fuses have 125 on each side grounded. Only the one 60 amp will show 240 touching each end. Fuse is good but the one 60 and both 30's wont show anything touching each end together. Here is a problem where something is wrong. Breaker is good, main power shutoff is good. Nothing tripped all working and on it is something in the air handler unit where the fuses and other parts are...

 

I am assuming you have cartridge type fuses. To test those place your meter on ohms. Touch the two leads together you should show 0.0 ohms. Some meters have a beep function that tones when you touch the leads together. The 0.0 reading or beep shows there is continuity. To test the fuses to see if they are good. Touch one lead to each end of the fuse. If the fuse is good it will read 0.0 or beep. If it shows OL or 1 on some meters the fuse is blown and needs to be replaced.

 

Ive already done that fuses are good. Continuity check on all 4 shows good. I have the audible beep and all four beep. I had the one bad I checked last night which is why I was hoping replacing it this morning would fix it but it didn't. So yes all four fuses are good. Remember I have been a mechanic for years so I am not a dumb homeowner who doesn't know how to do much when it comes to fixing things. I can do a lot but haven't messed with HVAC much so need assistance with it. I know about some of it but that's why I joined here to ask you guys that know a lot more about it. I appreciate all you are doing to help me however you are a big help. I don't know what goes where and readings should be where I just know what things are. Anyway whats next...And yes cartridge fuses...

 

We can't see what you see as we are not there. If you have power at the electrical panel then you should have power up to the air handler. If those cartridge fuses are in a box before they go into the air handler test for 240V inside that box at the lugs where the wires come in from the electrical panel. Look for burned wires inside that box. If you are able to post photos it would be very helpful to allow others to assist.

 

I was trying to upload a pic but at the moment wasn't having any luck getting it from phone to website. Ill try later. At the main shut off there is only a pull plate with prongs. When pluged in I have 240 top and bottom so in and out. To the air handler where all four attach we have 125 on each wire that goes to each fuse. 125 on other end on each fuse BUT only 240 on ONE big 60 amper. All three others show 000. Fuses show good so there is something strange going on somewhere... Why don't we have 240 on all four? Should we have 240 on all four? If all fuses are good then why only ONE showing 240 on both ends? That seems odd to me... I have to leave at 4PM EST to go pick up my other half so may be awhile before I get back to post again. Thanks for everything so far though we are making progress anyway...

 

Can you post the model number of your air handler? I am thinking you are testing the voltage incorrectly. You test the voltage much like you do at the contactor. You test across two in-coming 120V wires and across the two wires going out after the fuse.

 

RHQA-1315J Rheem

I also checked as you asked if you reread the posts. I check everything. Might not mean anything to you or in diagnosing the problem but its just my curiosity and wanting to know whats what. I like knowing what it reads everywhere it helps. Me understand better.

If you reread you will also see i checked. Where you asked me too. I thought knowing it all might help since you cant see what i see. I wont post what else i do from now on but only what you ask for. What are you thinking now? Every thing you asked about i checked as requested. The rest is just me wanting to know what it is everywhere...

 

Ok on the front or in from master disconnect box there are four wires. Two small and two large. On incoming small wires i have 240. Also on two large wires across incoming we have 240. On back side of fuse or out we have 240 on small wire BUT large wire across out side we have. 000.

 

Is that the disconnect box that supplies the air handler? Difficult to picture what type of box you have for the cartridge-type fuses. Is it something like the one in the attached photo? If you follow the large cables into the cabinet of the air handler there should be some lugs that the two 120V wires are connected to. The wires should enter where the compartment that houses the electric heat strips, There will be L1 and L2 wires. That is where you would test to see if you have 240V. I'll see if I can locate a wiring schematic for your air handler.

 

It sounds like Nickolas is describing the fuse block found inside of an air handler.

With 15 KW heat strips you often see 2 larger 60 amp fuses and 2 smaller 30 amp fuses.

Possibly something like this Rheem fuse block...


Were the fuses removed from the fuse block and place on a non-conducting surface (or held in your hands) for the Ohm test?

 

Looks exactly like that yes. I held them in my hands doing a continuity test. One end of the fuse i held a test lead on while i touched the other end with my other hand with the second test lead.

 

Yes L1 and L2 are the large leads coming from the disconnect box that is where i got 240 in and on the other end of those same two i got 000 on the meter. Straight across the fuse block or out. I did the two small wires in and out and got 240 on both sides for that check. Only the L1 L2 out i get 000 or nothing.

 

A, C and D should read 240 volts if you have good fuses installed.
The remaining letters should read 0 with good fuses installed.

 

Ok I have heat now it's fixed. Took all four fuses OUT of the air handler and did a continuity test on a board out of my hands to be non conductive and discovered I had yet another bad fuse. This time a 60 amp didn't have continuity. Just a simple thing as I thought it would be. I discovered the 30 amp the other day and missed this one somehow. I don't know really sometimes I just miss things and am a bit forgetful. After you asked me to remove them and put them on a non conductive surface I then saw I had another fuse bad. I had the 30 amp in my hands the other day when I tested it so I don't know how I missed the 60.

Anyway it's working and I thank you guys for your time, suggestions and guidance on this issue. Appreciate all your help you have given me. Back in business and heating away... I have a woodstove for a back up so I did have heat downstairs but this is good as to keep it at least around 66 if the fire goes out. Im good.

Thanks again for all who helped,

Nickolas

 

Glad to hear you are back up and running! Thanks for the update as it will help others in the future.

 

A reading of 240 volts at B, F, G or E would indicate a popped fuse.