Heat Pump problems

[djedgar]

We have a Duo-Therm 60515 heat pump (13,500 BTU) that recently went out of commission on our mh and are evaluating our options. We have a 2007 Newmar with dual heat pumps on the roof plus a furnace below. The heat pumps feed into ducts and we have a 5 button Comfort Control Center for the two zones.

The front unit stopped heating or cooling but the fan just runs. I removed the unit cover and noted a definite click around the compressor area. The tube feeding the reversing valve started to get quite warm so assume the compressor is operating. I can disconnect a lead to the reversing valve solenoid and hear definite clicks. From an internet search I read about using a magnet to see if the reversing valve moved internally and did notice that with the use of a magnet I feel attraction to spots that do seem to move back and forth when I connect and disconnect the solenoid. As mentioned, the tube from the compressor to the reversing valve does get pretty warm to hot, but the three tubes leading back to the compressor, inside and outside coils all feel about the same in temperature.

So based on all this my guess is that the reversing valve, while moving internally, is not fully shifting and thus not sealing the ports properly. Does this sound reasonable and can just the reversing valve be replaced. If so is it worth it?

Camping World seems to be having a sale on new Penquin units for the next couple days. The new units appear to be more efficient and a 651816 (15,000 BTU) runs at less amperage and I assume . The new unit comes with a 12 button Climate Control Centerl which I understand to be much nicer but also understand that would not be compatible with our older bedroom zone so would have to keep the 5 button control and fit a downgrade kit to run the new unit with our 5 button control.

If when the other heat pump goes out and we upgrade that, then maybe we can use the supplied 12 button control if the same 4 wire phone plug is used.

[djedgar]

Yes, new ambient sensor was installed. I wondered what the difference was but did it according to the directions.

Steps I followed were:
1. Remove existing wires/connectors from original 12 button board and remove board.

2. Remove existing ambient sensor and install supplied sensor from kit

3. Cut slit in harness to relieve strain

4. Cap off yellow wire from fan

5. Plugged in both RJ-11 connectors, new red ambient sensor, white remote senor cable, blue freeze control, 6 pin connector to new 5 button board.

6. Set dip switch for furnace (all others off as this is a zone 1 unit)

7. Mount new board, and then black fan motor wire to T1, Red fan motor wire to T3, Violet RV wire to T4, 120V input black wire to left K6 terminal, blue compressor wire to right K6 terminal

8. Spliced second violet RV wire to white wire (which terminated at run capacitor with other white wires).

9. Connected 120 volt lines underneath, connected both furnace leads, connected both RJ-11 connectors, left the two yellow wires alone as nothing on MH to attach to.

10. Reset CCC to get FF code and gave test. AC, heat pump and furnace all ran fine.

11. Went to put cover on top but noticed RV solenoid was somewhat hot to touch (after a period of rest) and discovered it was energized with CCC in OFF position. The only time it seems to be not energized is when running in COOL mode.

Photos of my work available at: smtlm.org/heatpump.html

[dougrainer]

djedgar wrote:
Yes yellow wire was capped off (and did realize it was for med speed on the fan). The wires from our reversing valve are violet (instructions say also could be black). One is to the T4 terminal and one to the common white wires.

The cooling and heating work fine and no complaints there. I would have never realized the solenoid was energized at rest unless I happen to put my hand on it and it was fairly warm. No humming noise. Maybe this is normal but just does not make sense to me and not the way I would have designed it. I will probably end up shutting off the circuit breaker to that unit while in storage or non use.

I appreciate all your help Doug. You seem to know your stuff. I would be most interested if you can check the next time you do one of these. Easiest way is to plug into shore power and you can hear it click on, or off when disconnecting (assuming no extraneous noise covers it up).

DID you replace the included Ambient sensor also? THAT is also required. The 12 button board and the Ambient sensor on the new HP is NOT compatible with the 5 button board. The 5 button, what tells the system you have a HP is THAT Ambient Sensor. On the 12 button, you have a DIP switch that you flip to tell the system you have a HP. The Ambient sensor on the 12 button if connected to a 5 button board will cause problems. THAT 5 button ambient sensor included in the kit is the 1 BIG difference rather than just installing the OLD 5 button board on your new 12 buttom HP. So, you cannot just swap boards, you HAVE to swap the Ambient sensor also. Granted, you could purchase a 5 button Ambient sensor and install it with the OLD board and save some money. Doug

[djedgar]

Yes yellow wire was capped off (and did realize it was for med speed on the fan). The wires from our reversing valve are violet (instructions say also could be black). One is to the T4 terminal and one to the common white wires.

The cooling and heating work fine and no complaints there. I would have never realized the solenoid was energized at rest unless I happen to put my hand on it and it was fairly warm. No humming noise. Maybe this is normal but just does not make sense to me and not the way I would have designed it. I will probably end up shutting off the circuit breaker to that unit while in storage or non use.

I appreciate all your help Doug. You seem to know your stuff. I would be most interested if you can check the next time you do one of these. Easiest way is to plug into shore power and you can hear it click on, or off when disconnecting (assuming no extraneous noise covers it up).

[dougrainer]

1. DID you cap OFF the yellow wire??????? You MUST cap that wire OFF per the instructions. IF you connected that Yellow wire, that will cause problems. The yellow wire on the 5 button boards is the REVERSING signal wire. On the 12 button Boards, it is the Medium Fan speed wire. The 5 Button HP's only had 2 fan speeds. Hi and Low. The 12 button's have Low-med-Hi. But, the Yellow wire is NOT used on the Coversion kit wiring. The Reversing solenoid wires are seperate and that is why you connect to T4 on the board and the other wire to the generic White Neutral harness. I have done about 10 of these and have NEVER had a problem. Doug

[djedgar]

More on the saga.

Dometic contacted us and gave us the wiring diagram for the heat pump when used with the 5 button CCC. Turns out to be the same diagram as what was in our old unit. And sure enough both the old unit board and the new conversion kit board have the same numbers on it. Could have saved $100 except that I got the instructions. However the diagram Dometic sent showed the reversing valve wire connected to terminal T2 (like on my old unit) rather than T4 like the kit directions gave us. Sure enough, the solenoid was no longer energized with CCC in OFF position . . . but the unit heated when set at cool and cooled when set at heat.

So on the off chance our new board was defective, I took the told board out of the old unit and put in in the new unit. Worked the same.

I have another inquiry to Dometic regarding the energizing of the solenoid at rest. They keep skirting that question. They do say there is phantom power in the system as has been for all their units for years. My zone 2 heat pump does not have the solenoid energized at rest. And there should be a difference between phantom power and the solenoid being fully energized. Dometic said the phantom power actually saves on the equipment but in order to cool, the solenoid had to be deactivated so what is that logic?

[djedgar]

I am sure I wired it up per the directions (but have done dumb things in the past) so to be sure I went back and checked. I pulled it apart and noted everything checked out. I then reconnected it all back together carefully. The only thing I discovered was that I had not set one of the dip switches to include the furnace. But bottom line is with the 5 button CCC in the OFF position and shore power plugged in, the reversing valve solenoid is energized. If I connect and disconnect the violet solenoid wire, I can hear a solid click and I can feel something if I put my finger on the solenoid so it definitely is energized in the CCC OFF position. Please excuse the length of this as I am trying to accurately describe what I have done. I do not know how to display photos here but can temporarily display them here: http://www.smtlm.org/heatpump.html

Just to be clear, this is a Penquin II high capacity heat pump with conversion module PCB (3313107.107 kit) to operate with existing 5 button CCC. Also have a zone 2 heat pump and a furnace. Going on a 2007 Newmar Ventana after original zone 1 heat pump went bad.

I followed the Service Instructions that came with the conversion kit (form #3314520.010)
There were no instructions that came with the heat pump but wiring was pretty much straight forward. The 120 (hot, common and ground) was simple. The 12VDC and ground matched up. There were two furnace wires and it did not seem to make any difference how they matched up to the two MH furnace wires. Ditto with the two four wire cable phone type connectors. The only wires not used were two yellow wires from the heat pump that came from the 6 pin connector (LOAD SHED). Nothing from the MH side to connect to.

I again reset the CCC. I then put it into the cooling mode. The solenoid was energized while the fan blew for 2.5 minutes, at which time the solenoid disengaged, then the compressor started up and cool air ensued.

I then set the CCC to heat pump (the solenoid then energized) and the fan blew for 2.5 minutes at which time the compressor started up and hot air ensued. If I disconnected the solenoid the reversing valve would click and the compressor would stop.

So if I am on shore power, the default is to have the solenoid energized and reversing valve is in the heating position.

If not on shore power, then the solenoid is not energized and the reversing valve is in the cooling position.

I did contact Dometic regarding the solenoid being energized with shore power and CCC in the OFF position. Also said I read 120 VAC at the board terminal marked Violet. Their email reply was:
=======================
David
Just because you have volts does not mean the circuit is active.
Attached is a service bulletin on the 5 button system.
We appreciate this opportunity to address your situation, and hope all your future travels are trouble free. Please do not hesitate to contact us any time, to order parts or if we can be of assistance.
=======================

I then got another reply by someone else at Dometic.
=======================
Dear David ,

When plugged in the AC/HP will experience what we call Phantom voltage ( which is you will have voltage on all circuits -( ie..fan , hi-lo) , this is normal . The reversing valve is energized in the heat mode not cool mode like the older units .
Thank you for contacting Dometic

Sincerely
Dometic Customer Support
=======================

Neither addressed if having the solenoid energized while on shore power and CCC OFF is normal. I will ask again. Just does not make sense to me to have the solenoid energized while CCC is OFF.

[PaulJ2]

Altern wrote:

dougrainer wrote:
Heat Pumps "usually" last no more than 5 to 8 years.

Its the 5-8 years that call attention & disagreement.
If you had said 8-10 its more palatable and somewhat closer to fact.
Personally, I would have said 10-12.

Its a funny biz though... I've seen really old Carrier's that lasted 30 years and on the other hand, say in the early 80's when for a period, they used Bristol compressors and had a very high failure rate.

First heat pump in the house went 9 yrs and lost a compressor (warrenty). Second compressor is on it's 14th yr. Everything else is original unit yet except I oiled the outside fan motor once(knock on wood). Yeah, you would think it should last 30+ years as many refrigerators/freezers do, but i guess the complicated switching valves and stuff just gives up.
Keep up the good work Doug.

[dougrainer]

Are you POSITIVE that you did all the conversion wiring correctly? You HAVE to follow the directions in order if you have never done it before. But, no, the solenoid valve should NOT be hot all the time. Part of the 12 to 5 conversion has to do with the Reversing valve wiring. The NEW 12 button boards, the default is for the unit to cool instead of heat on the Heat Pumps. So, the default on a 12 button is to have NO power to the reversing solenoid and it will cool. If you power the valve it will heat. That is why I think you miswired the conversion kit. Doug

[djedgar]

Well we ordered the Penguin II high capacity heat pump along with a conversion kit to run it with our 5 button CCC. Installed it yesterday and it cooled on a quick test. But in double checking things I noticed that the solenoid on the reversing valve was energized even with the CCC in the OFF position and MH hooked to shore power. Disconnected the shore power and the solenoid was un-powered of course. Does this sound right? I have the MH plugged in when not in use so the solenoid would be energized all the time now. If I touch the solenoid it is somewhat hot.

Just to confirm, I did do the CCC reset after the install and got the FF code. CCC switch was in the OFF position. I had set the zone 1 (where the new HP is located) to OFF mode before turning off the CCC. Conversion board instructions say to plug one purple reversing valve wire to the T4 terminal marked Violet and the other purple reversing valve wire to the white wire (which leads to the capacitor and joins with other common lines). And with the purple wires unplugged, I get 119VAC at the T4 terminal (with shore power connected).

[Altern]

dougrainer wrote:
Heat Pumps "usually" last no more than 5 to 8 years.

Its the 5-8 years that call attention & disagreement.
If you had said 8-10 its more palatable and somewhat closer to fact.
Personally, I would have said 10-12.

Its a funny biz though... I've seen really old Carrier's that lasted 30 years and on the other hand, say in the early 80's when for a period, they used Bristol compressors and had a very high failure rate.

[dougrainer]

c.traveler2 wrote:

dougrainer wrote:
Heat Pumps "usually" last no more than 5 to 8 years. Same for residential Heat Pump units. I state this for people that are using their unit MORE than 8 months a year. Since Heat Pumps cool and heat, they are run twice as much so they will wear out twice as fast. Now, if you full time and stay in a warm climate, your Heat Pump will still be used as much as a standard AC unit. Since Rv's are usually recreational and NOT full time homes, the AC or HP may last 10 years or more, it all depends on how many days a year the HP is used. Doug

Doug, you maybe correct about RV heat pump units lasting 5-8 years, but your giving miss information about residental heat pump units lasting only 5-8 years. There are thousands of residential units that are 25 plus years old and running just fine. I am a HVAC contractor in California, I recently changed out a heat pump system that was 35 years old, so please don't compare a residential heat pump system with a RV heat pump system when it come to longevity.

I do enjoy reading your anwsers to many of the RV related problem and have learned from those answers, keep up the good work.

I base MY comments on residential on my OWN experience with Heat Pump in my old house. And Friends also. I had to replace the complete system after 8 years and when I had 4 different HVAC contractors come out to give estimates, and I asked WHY I had to replace so soon, they ALL stated that due to double duty (Heat and COLD) they wear out twice as fast. Sorry, but it makes sense to me. Yes, some may last longer, but It all depends on how well the maintenance was and how often it was run. Doug

[c_traveler2]

dougrainer wrote:
Heat Pumps "usually" last no more than 5 to 8 years. Same for residential Heat Pump units. I state this for people that are using their unit MORE than 8 months a year. Since Heat Pumps cool and heat, they are run twice as much so they will wear out twice as fast. Now, if you full time and stay in a warm climate, your Heat Pump will still be used as much as a standard AC unit. Since Rv's are usually recreational and NOT full time homes, the AC or HP may last 10 years or more, it all depends on how many days a year the HP is used. Doug

Doug, you maybe correct about RV heat pump units lasting 5-8 years, but your giving miss information about residental heat pump units lasting only 5-8 years. There are thousands of residential units that are 25 plus years old and running just fine. I am a HVAC contractor in California, I recently changed out a heat pump system that was 35 years old, so please don't compare a residential heat pump system with a RV heat pump system when it come to longevity.

I do enjoy reading your anwsers to many of the RV related problem and have learned from those answers, keep up the good work.

[dougrainer]

Heat Pumps "usually" last no more than 5 to 8 years. Same for residential Heat Pump units. I state this for people that are using their unit MORE than 8 months a year. Since Heat Pumps cool and heat, they are run twice as much so they will wear out twice as fast. Now, if you full time and stay in a warm climate, your Heat Pump will still be used as much as a standard AC unit. Since Rv's are usually recreational and NOT full time homes, the AC or HP may last 10 years or more, it all depends on how many days a year the HP is used. Doug

[djedgar]

Out of curiosity how long should a heat pump last in years or hours? Should I expect my second 6 year old unit to be on its last legs? We ran the front unit more than the back so would expect it to go out first. But then the front also had the copper tube rubbing on the compressor which hastened its earlier demise.