Waeco Coolmatic Fridge Problem

[Sidclark]

I've got a Waeco Coolmatic RPD-190 fridge and the issue is I have frost building up on the back wall of the fridge. Also, the compressor seems to run continuously which is probably related to the frosting issue. I defrosted today and within 30 minutes frost was forming on the back wall. The fridge does have a muffin fan attached to the ceiling on the right side. I'm not sure if this is factory or not, but it's not running. I have tried to check the seal with a piece of paper and the paper did have some resistance to being pulled out. How much resistance should there be with a good seal? I'm thinking the seal is gone, but what are your guys thoughts?

I have tried to find a replacement seal but no one knows if a Dometic Coolmatic RPD-190 seal will work or not. Dometic website is no help at all and will not even recognize the part or article number. I'm sure someone out there has this same fridge and ordered parts, but from where? By the way, the fridge is almost empty with just a few sodas inside. Thanks for any help in this!

 

[rgano]

Not being in anyway an expert, but I will assume them that are will soon chime in with the thought that the coolant level is low.

 

[Portage_Bay]

I'm having similar problems with a smaller Isotherm fridge / freezer. Frosting, continously running.

Chatting with an expert at a top rated shop that sells and services the units. I learned that air flow through the cabinet is critical. I increased the size of the air exit and installed a fan the size of the enlarged opening. I wired the fan to run with the compressors fan.

That has solved the continuous running but it's still icing up.

Reading troubleshooting info if the back wall ices up top to bottom that is considered to be good. Part of the back wall not good.

I asked about replacing the compressor and or recharging the unit and I was advised not to waste my money on that. This from a shop capable of and happy to do the work if I choose to.

The advise was what I did and run the rest of the life out of it. Then replace.

For what it's worth the Norcold about the same size as yours in my previous boat also iced up the back wall.

 

[Sidclark]

That's interesting. Mine is icing up from top to bottom also. I'll check airflow...

 

[Comodave]

We have a Vitrifugo that didn’t cool well. Added a low and high vent in the cabinet and a fan pushing air in at the bottom vent. The fan is hooked to the circuit board and runs whenever the compressor is running. Made a world of difference. Also we have a small fan that runs inside the refer to circulate the air inside. It runs on a D cell.

 

[Portage_Bay]

I'm onboard now. Air temp in the cabin is 67 F. Outside is cooler, maybe 60? The air coming out the fan forced vent is noticeably warm. This tells me the cabinet exhaust fan is doing some good. But maybe it needs to be bigger? Or maybe run longer? As I type this I'm observing the compressor is running but the fans, both the original refer fan and the newly installed cabinet fan are not running.

I have a lot to learn. But these compressors are small and their cooling area is small compared to regular household refers. And we have them built in where cooling air circulation is limited.

We are asking a lot of these boat refer systems.

That's interesting. Mine is icing up from top to bottom also. I'll check airflow...

 

[Comodave]

Couple of ways to power the fan, easiest is if there is a terminal on the circuit board that supplies power to the fan when compressor is running. My Vitrifugo has such a point, terminal F supplies up to 1/2 amp 12 volts DC for a fan. I bought a fan on Amazon that draws 50 mAmps or .050 amps. The other way is to put a temperature sensor to turn the fan on/off. This is the fan I used.

Noctua NF-F12 PWM, Premium Quiet Fan, 4-Pin (120mm, Brown)

 

[Portage_Bay]

I powered the cabinet fan off the refer fan, no terminal board but not difficult to wire in. Mechtronics 120 mm 18 mAmps.

What I'm noticing is the cabinet is still too warm. I should have run a separate power supply for the fan, thermostatically controlled. It would run more than the compressor and fan but that seems to be what's needed. The PO put such a large refer in there is only about 3/4" clearance on the sides and top and 1 1/2" on the back. The exhaust hole is as far from the compressor as it can be and not at the top of the cabinet. All choices made due to interferences.

Couple of ways to power the fan, easiest is if there is a terminal on the circuit board that supplies power to the fan when compressor is running. My Vitrifugo has such a point, terminal F supplies up to 1/2 amp 12 volts DC for a fan. I bought a fan on Amazon that draws 50 mAmps or .050 amps. The other way is to put a temperature sensor to turn the fan on/off. This is the fan I used.

Noctua NF-F12 PWM, Premium Quiet Fan, 4-Pin (120mm, Brown)

 

[Comodave]

The fan you are using draws more than 3 time the one I am using. Maybe change to a smaller draw fan and add one or two more fans to move more air fir the same or less current draw. Do you have room for more fans? You might also be able to swap out the compressor fan if it draws more than 50 mAmps. The fan I put in is really quiet. I can’t hear it run but can tell that there is air flowing. If you only have a narrow space behind the refer, maybe route a slot on the top of the cabinet to let the hot air out of the cabinet. Just guide the router carefully so it doesn’t get out of control. Clamp a guide board in place to keep the router under control. Maybe???

 

[Portage_Bay]

That's an impressive fan you've found. Had I known about that one I'd have used it. Maybe next time I pull the refer out I'll change it out.

Regarding routing a hole in the cabinet top. I want to avoid that because it is the main food prep area in the galley. Trying to keep that clear and clean is a battle I don't want to fight.

More fans may help, but it's a matter of air flow path as well as air flow volume. Difficult to describe with text, but here goes. The compressor and fan sit in a small cubic space on the top back left side of the box. The only reasonable outlet from the cabinet other than the hole in the counter top is back right side lower than the top of the box. Interferences are from the cabinet framing and the sliding door to the deck. Going through the cabinet to the right is the galley stove and oven, not an option. The other way is right above the cabinet air inlet and I think all that would do is circulate air on that side of the refer cabinet without helping the compressor / fin space much. And I'd have to carve out the back of the storage cabinet to the left and put a grill in that cabinet's door. A lot of effort for something I'm not confident will make a difference.

I'm thinking a thermostatically controlled fan may work better. When the compressor fan and the cabinet fan I added shut down there is residual heat in the compressor and fins that continue to warm the space up. So when the compressor next cycles on the cooling fins are already behind the curve working with warmed air. On a warm day so warm the counter top is warm to the touch and that's a thick plywood base.

The fan you are using draws more than 3 time the one I am using. Maybe change to a smaller draw fan and add one or two more fans to move more air fir the same or less current draw. Do you have room for more fans? You might also be able to swap out the compressor fan if it draws more than 50 mAmps. The fan I put in is really quiet. I can’t hear it run but can tell that there is air flowing. If you only have a narrow space behind the refer, maybe route a slot on the top of the cabinet to let the hot air out of the cabinet. Just guide the router carefully so it doesn’t get out of control. Clamp a guide board in place to keep the router under control. Maybe???

 

[Comodave]

Well with the 50 mAmp fan you could just put a switch on it and turn it on when you turn on the refer and turn it off when you turn off the refer. You could also just wire it to the 12 volts going to the refer if you run it on 12 volts all the time and not 120 volts. But I would at least put a small fuse and switch in the power wire to the fan. A 50 mAmp load isn’t much to worry about because the compressor is probably going to run half the time anyway.

 

[Portage_Bay]

Good points. Easy to do.

 

[Sidclark]

That's interesting. Mine is icing up from top to bottom also. I'll check airflow...

So I got to poking around today with the perspective of an air flow issue and here's what I found. The back of the fridge shares a wall with the front cabin. At the bottom of that wall in the front cabin I found a louvre that was about 6x10. Removed the louvre and there was a fan, I believed to be the compressor fan, that was clogged with dust and dirt. Vacuumed the screen clean and made sure fan was running. Coming back into the galley I noticed another louvre along the side wall that encloses the right side of the fridge. Took off the louvre and nothing there. On the opposite side of the fridge, I found another fan that was obviously installed there by the PO. It was not running, so I'm not sure if it supposed to blow or suck air from the enclosure. And the small fan inside the fridge is not running. I think from what I gather here if I get these fans running that may solve the continuously running compressor. Thoughts? The fridge is drawing about three amps when running. Sound about right?

 

[Comodave]

3 amps is pretty good, some are more. I would get the fans running or replace them with very low draw fans. I posted one above that only draws 50 mAmps. Then have the fans blowing in on the bottom or out on the top. Do you have a vent on the top? If not try to make one so the hot air can get out. It will make a big difference. Here is one RV refer fan to circulate the air inside the refer.

FridgeCool Fan W/ On/Off Switch A10-2606

 

[Sidclark]

Don't cha love it when small issues start to snowball? I took another look at the upper fan the PO installed and it's not a 12 volt fan, it's 120. So I flipped off the 12 volt breaker to the fridge and flipped on the 120 breaker to the fridge. Took a look at that 120v fan again and noticed it's running pretty slow. Then I decided just for giggles, let's run the fridge off the invertor. Low and behold, now the fan is running full speed. Switched back to shore power and fan slows back down. This is starting to climb above my paygrade here. I did notice the compressor seems to be cycling when the fridge is running on 120. Thoughts on that? The inside fan seems to be dead, it doesn't run on 12 or 120 volt. Strange stuff here....

 

[Comodave]

Don't cha love it when small issues start to snowball? I took another look at the upper fan the PO installed and it's not a 12 volt fan, it's 120. So I flipped off the 12 volt breaker to the fridge and flipped on the 120 breaker to the fridge. Took a look at that 120v fan again and noticed it's running pretty slow. Then I decided just for giggles, let's run the fridge off the invertor. Low and behold, now the fan is running full speed. Switched back to shore power and fan slows back down. This is starting to climb above my paygrade here. I did notice the compressor seems to be cycling when the fridge is running on 120. Thoughts on that? The inside fan seems to be dead, it doesn't run on 12 or 120 volt. Strange stuff here....

Yes, have you sneaked up on it in the dark and looked for gremlins? It does sound strange. The inside fan, is it 12 volt or 120 volt? Also don’t understand the difference in fan speed on shore power vs inverter.

 

[Sidclark]

Yes, have you sneaked up on it in the dark and looked for gremlins? It does sound strange. The inside fan, is it 12 volt or 120 volt? Also don’t understand the difference in fan speed on shore power vs inverter.

The inside fan looks like the wires run to the thermostat box so I'm going to assume it's 12 volt actuated by the thermostat. I'll get in there and remove it and then know for sure. The 120 volt fan runs constantly whenever the fridge is running on 120. The difference in speed has me baffled...

 

[Irish Rambler]

Interesting posts of different experiences.
In the past I've had Electrolux, Dometic and Waeco fridges which definitely worked, indefinitely !
I bought a Vitrifrigo and it's definitely been the best by a long chalk, part of the the bilges are directly below our galley so before I fitted our floor standing fridge I drilled a line of 1'1/2" holes along the floor in line with back of the fridge so that as the hot air rises from the back of the fridge it draws cool air up from the bilge by thermal convection. We have a 3/4" space around the sides and top of the fridge to help air flow and each spring and autumn we empty the fridge, remove it, and vacuum/clean the grill of the accumulation of static dust at the rear as part of our scheduled maintenance routine.
Each boat and its systems are slightly different and the beauty of TF is the pool of knowledge gained from others experiences.
I'm often amused by everyone's increasing dependency on electronics I think I must be just be old fashioned as I like to keep things simple for easy stress free cruising.

 

[Sidclark]

We have a 3/4" space around the sides and top of the fridge to help air flow

The PO has added insulation to the sides and the top so there's no air flow at all except for the back. Now I'm wondering if that's a problem. If I had a manual showing clearances that would be a great help, but so far I haven't found one.

 

[Comodave]

We don’t have much, if any, clearance on the sides but we do in the back and on top for the not air to rise and exit on the top.

 

[Sidclark]

Yes, have you sneaked up on it in the dark and looked for gremlins? It does sound strange. The inside fan, is it 12 volt or 120 volt? Also don’t understand the difference in fan speed on shore power vs inverter.

Checked the fan on the inside today and it's a 12 volt fan, it's shot though. However, when the fridge is running on 12 volts, I have 13.8 going to the fan and fridge light, but when it's running on 120 volts the I have 26 volts going to the fan and light. This doesn't make any sense to me at all, but electrical stuff is a shortcoming to me beyond the basics. The fan is connected to the thermostat wiring, if that helps. It seems to me whatever 12 volt fan I install in there is going to get fried when it gets hit with 26 volts. Thoughts on this??