FIXED: Fan Noise from Converter (replaced unit)

pbeyser

Member
I am a brand new owner of a 2009 North Trail 21FBS. It is our first rv. There is a fan going continuously from the converter when the trailer is connected to the battery. The first night after we took possession, the only way I could shut the fan off, was to disconnect the battery. Even turning all the breakers off would not stop the fan. Now that I have it plugged in on my driveway, the fan runs continuously. Is this normal? The only way to shut it off is to switch off all the breakers.

When using the battery only, how can I shut down the fan? Removing the fuse works but that does not seem like a good solution. The label on the converter says WFCO 3-Stage Converter. Thanks in advance for your help.
 

danemayer

Well-known member
Re: Fan Noise from Converter

Hi pbeyser,

I'm a little confused. The Power Converter changes 120V AC into 12V DC. It gets power when you're plugged into shore power and it's output is to both the fuse box fuses, and to the battery. It shouldn't be doing anything when you're running the rig on battery power only. I'm also confused because you said you could only shut the fan off by pulling a fuse or by disconnecting the battery, but also said you could shut if off by flipping all the circuit breakers off.

Can you clarify?
 

pbeyser

Member
Re: Fan Noise from Converter

Hi pbeyser,

I'm a little confused. The Power Converter changes 120V AC into 12V DC. It gets power when you're plugged into shore power and it's output is to both the fuse box fuses, and to the battery. It shouldn't be doing anything when you're running the rig on battery power only. I'm also confused because you said you could only shut the fan off by pulling a fuse or by disconnecting the battery, but also said you could shut if off by flipping all the circuit breakers off.

Can you clarify?


The first night we owned it, we had to park it at the local park because I could not get it into the driveway without grounding out. That evening we went to check on it. It was not plugged in. I went inside and noticed the fan noise coming out from the converter box. I hunted around for a master shut off but found nothing. I phoned the previous owner and she told me to disconnect the fuse. That shut the fan down but there was still power being used from the battery as evidenced by two pilot lights, one on the cable TV outlet, and one on the stereo. I then disconnected the battery. I was worried that the battery would be dead by morning as a result of the fan running and the pilot lights on. I hope this makes sense!
 

Oregon_Camper

Well-known member
Re: Fan Noise from Converter

Did the original owner install an inverter? If so, I'm guessing they wired it directly to the main circuit panel, therefore you have a power loop and the battery is indeed causing the converter to run.

If so...there should be an on/off switch for the inverter inside the trailer. If no switch, go look for inverter and turn off there. You can find it by following Positive off battery....cable should be no more than 10 feet for proper inverter install.
 

pbeyser

Member
Re: Fan Noise from Converter

We are the third owner so I'm not sure. How could I investigate this for myself? Is a power loop bad? I've read on another site that the fan may simply be running due to heat build up in the unit. It was suggested that I vacuum out any dust or pet hair.

Did the original owner install an inverter? If so, I'm guessing they wired it directly to the main circuit panel, therefore you have a power loop and the battery is indeed causing the converter to run.

If so...there should be an on/off switch for the inverter inside the trailer. If no switch, go look for inverter and turn off there. You can find it by following Positive off battery....cable should be no more than 10 feet for proper inverter install.
 

Oregon_Camper

Well-known member
Re: Fan Noise from Converter

We are the third owner so I'm not sure. How could I investigate this for myself? Is a power loop bad? I've read on another site that the fan may simply be running due to heat build up in the unit. It was suggested that I vacuum out any dust or pet hair.


The converter can only run on AC power. Its job is to create DC power for the RV and to charge battery.

Yes...a loop is bad. You would be creating AC power from battery....sent to Converter to create DC power to charger battery....then all over again. You will lose power at each phase.
 

danemayer

Well-known member
Re: Fan Noise from Converter

If you have a fan running when the coach is not plugged into shore power, as Oregon_Camper suggested, you may have an aftermarket inverter that's converting the battery power into 120V, powering the Power Converter. If that's what's happening, you should be able to turn off circuit breakers one by one until the Power Converter stops getting power and the fan goes off.

Maybe we should ask how you know it's the Power Converter fan that's running.
 

pbeyser

Member
Re: Fan Noise from Converter

Ok I have some more information that might be helpful. The previous owner has reported that when she plugged in a hairdryer some time ago, she blew some fuses, after which, one circuit breaker kept popping. She had it replaced by her "electrician" friend who also noticed that the fan in the converter was not working properly. I have taken the cover off the converter and discovered that he appears to have bypassed the fan thermostat by cutting off the plug and using alligator clips to rewire so that the fan never shuts off.

The only way to shut the converter fan off is to remove the fan fuse or disconnect the battery. I've attached a few pictures to help explain. The question is, what to do next? Is this worth fixing or does it seem like a replacement is in order?

Thank you for any help you can offer!


If you have a fan running when the coach is not plugged into shore power, as Oregon_Camper suggested, you may have an aftermarket inverter that's converting the battery power into 120V, powering the Power Converter. If that's what's happening, you should be able to turn off circuit breakers one by one until the Power Converter stops getting power and the fan goes off.

Maybe we should ask how you know it's the Power Converter fan that's running.
 

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danemayer

Well-known member
Re: Fan Noise from Converter

Ok, this is starting to make more sense. I think the friend with electrical experience who worked on this previously must have wired the fan directly to a 12V DC source. Normally the fan only runs when 120V shore power is present.

This will be a problem when the trailer is running on battery power because of the extra load on the battery. And of course it's noisy all the time.

If everything else is working ok, and the noise is tolerable, you might just add a switch on the fan's hot wire so you can more easily shut off the fan when you're not plugged into shore power. That'll reduce the unnecessary load on the battery. Because the current wiring doesn't include a thermostatic control, you probably want the fan running all the time when on shore power to keep it from overheating.

If you want to get back to a normal operation, assuming the prior finding on the fan was correct, I think you'll have to replace the entire unit and hope there are no additional surprises in the electrical wiring.
 

cookie

Administrator
Staff member
Re: Fan Noise from Converter

Well, if a previous owner plugged in a hair dryer that should have nothing to do with a 12 volt fan. So that leads me to believe that there may be another problem not related to the 120 volt hair dryer issue.
You can replace the converter relatively inexpensively.
Here is a 55 amp replacement on Ebay for $140. Click here.

Peace
Dave
 

wdk450

Well-known member
Re: Fan Noise from Converter

Well, if a previous owner plugged in a hair dryer that should have nothing to do with a 12 volt fan. So that leads me to believe that there may be another problem not related to the 120 volt hair dryer issue.
You can replace the converter relatively inexpensively.
Here is a 55 amp replacement on Ebay for $140. Click here.

Peace
Dave

You MIGHT be able to lube the fan with a light machine oil (like 3 in 1 oil) delivered by a small medical syringe and needle. The far end bearing away from the fan blades might just have a paper cap over the bearing, but might have a metal cap. You might even be able to get the syringe needle between the fan blades and the fan motor to try to get some lubrication on the front fan bearing. BTW, the oil will swell the rubber plunger of the syringe and it will be very quickly hard to operate.

If you can get enough access to see the fan, is it possible for you to remove it? Most component parts are stamped with part numbers that can be internet searched (Googled) maybe with the word "Fan" following the numbers. A fan is a lot cheaper than the $140 for a new converter. Because of the modifications made, I doubt if the converter manufacturer will help you with a part or exchange converter on this, but you may want to try it. If you DO buy a new converter, don't feel locked into this brand/model. Look for one with tri state (or better) charge modes. This greatly extends the life of your battery.

I am a retired electronics technician.
 

LBR

Well-known member
Re: Fan Noise from Converter

You MIGHT be able to lube the fan with a light machine oil (like 3 in 1 oil) delivered by a small medical syringe and needle. The far end bearing away from the fan blades might just have a paper cap over the bearing, but might have a metal cap. You might even be able to get the syringe needle between the fan blades and the fan motor to try to get some lubrication on the front fan bearing. BTW, the oil will swell the rubber plunger of the syringe and it will be very quickly hard to operate.

If you can get enough access to see the fan, is it possible for you to remove it? Most component parts are stamped with part numbers that can be internet searched (Googled) maybe with the word "Fan" following the numbers. A fan is a lot cheaper than the $140 for a new converter. Because of the modifications made, I doubt if the converter manufacturer will help you with a part or exchange converter on this, but you may want to try it. If you DO buy a new converter, don't feel locked into this brand/model. Look for one with tri state (or better) charge modes. This greatly extends the life of your battery.

I am a retired electronics technician.
I think the OP is more concerned about the converter fan running 24/7 and running down his batteries when not plugged into shore power than the fan making noise.... That's my jist from reading this thread anyway.
 

pbeyser

Member
Re: Fan Noise from Converter

I think the OP is more concerned about the converter fan running 24/7 and running down his batteries when not plugged into shore power than the fan making noise.... That's my jist from reading this thread anyway.


UPDATE

I replaced the converter today and everything seems to be working fine. My only concern was that the replacement converter from Parallax did not have a ground wire while the old broken one that I replaced did. Is this an issue? Why would the old one need to be grounded and not the new one? The instructions on the new one made no mention of a ground wire.

Thanks.
 

wdk450

Well-known member
Re: Fan Noise from Converter

UPDATE

I replaced the converter today and everything seems to be working fine. My only concern was that the replacement converter from Parallax did not have a ground wire while the old broken one that I replaced did. Is this an issue? Why would the old one need to be grounded and not the new one? The instructions on the new one made no mention of a ground wire.

Thanks.


It SHOULD be grounded with BOTH. the ground pin on the AC power input plug, and with the connection to the 12 volt negative cable. Both of these wires/cables should lead back to a frame ground.
 

pbeyser

Member
Hi - Thanks for your replies. I've attached the instructions of the Parallax Power Supply model 7155. The word ground does not appear in the document. How do I ground something that does not have a greeen wire?



From the Parallax 4400 documentation:
 

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danemayer

Well-known member
The 7155 documentation uses exactly the same language. 3 wire with ground.

The picture in the board replacement document clearly identifies the neutral buss bar. There is another buss bar at the top, which appears to be held in place by a bolt that goes through the frame of the converter.
Parallax 7155.jpg
While not labeled, I would guess that is the ground buss bar, which is where you would attach the bare copper ground wire from the 120V AC supply. The other end of that wire needs to be attached to frame ground, or to a buss bar that is in turn connected to frame ground.

You can verify whether this upper buss bar is a ground by checking continuity to the case of the power converter.

Let me suggest that if you're not certain about these things, you're getting into dangerous territory. The converter is supposed to be grounded to protect you in the event of a short circuit. If not properly grounded, you'll have a serious safety situation. If you're not sure, get a licensed electrician to help.
 

pbeyser

Member
The 7155 documentation uses exactly the same language. 3 wire with ground.

The picture in the board replacement document clearly identifies the neutral buss bar. There is another buss bar at the top, which appears to be held in place by a bolt that goes through the frame of the converter.
View attachment 50597
While not labeled, I would guess that is the ground buss bar, which is where you would attach the bare copper ground wire from the 120V AC supply. The other end of that wire needs to be attached to frame ground, or to a buss bar that is in turn connected to frame ground.

You can verify whether this upper buss bar is a ground by checking continuity to the case of the power converter.

Let me suggest that if you're not certain about these things, you're getting into dangerous territory. The converter is supposed to be grounded to protect you in the event of a short circuit. If not properly grounded, you'll have a serious safety situation. If you're not sure, get a licensed electrician to help.

Thanks for your reply and I appreciate your patience. The old converter green ground wire was connected to the buss bar on the lower left as you guessed. It is still unclear to me how to ground the new unit if it did not come with a ground wire included/attached. Also, I've re-read the instructions (the ones attached earlier), and still don't see a reference to grounding. Are you reading a different document than the one I attached?

Peter
 

danemayer

Well-known member
Thanks for your reply and I appreciate your patience. The old converter green ground wire was connected to the buss bar on the lower left as you guessed. It is still unclear to me how to ground the new unit if it did not come with a ground wire included/attached. Also, I've re-read the instructions (the ones attached earlier), and still don't see a reference to grounding. Are you reading a different document than the one I attached?

Peter
Peter,

On the Parallax website, for each model there is a set of documents including a operator guide. It doesn't provide a lot of information, but it does clearly say 3 wire with ground.

I wouldn't expect the new unit to come with wires. I'd expect that there would be wires already attached to the old unit. But considering some of the earlier posts about how previous owners and their techs had modified the installation, I'm not too surprised you can't find a ground wire. You may have to add one.

Generally the hot wire would come from the circuit breaker and the neutral wire would come from the neutral buss bar in the circuit breaker panel. Your circuit breaker box may also have a buss for ground wires. This picture is from a Landmark 365 where you can see hot wires attached to the breakers, neutral wires attached to a buss bar in front, and bare copper ground wires attached to another buss bar further back.
DSC04454.jpg
 

pbeyser

Member
Thanks again! I understand where the ground wire goes on the RV (left side buss bar), but how/where do I connect the other end, the end that connects to the replacement unit? There is no obvious attachment point.



Peter,

On the Parallax website, for each model there is a set of documents including a operator guide. It doesn't provide a lot of information, but it does clearly say 3 wire with ground.

I wouldn't expect the new unit to come with wires. I'd expect that there would be wires already attached to the old unit. But considering some of the earlier posts about how previous owners and their techs had modified the installation, I'm not too surprised you can't find a ground wire. You may have to add one.

Generally the hot wire would come from the circuit breaker and the neutral wire would come from the neutral buss bar in the circuit breaker panel. Your circuit breaker box may also have a buss for ground wires. This picture is from a Landmark 365 where you can see hot wires attached to the breakers, neutral wires attached to a buss bar in front, and bare copper ground wires attached to another buss bar further back.
View attachment 50613
 
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