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If you want the fan to run only when a compressor is running you could install two amp-clamp relays wired in parallel.

Use something like a RIBXKTA.

No wait - I just realized: all you need is one as it can sense from either of two wires through it. <g>

PHM
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Originally Posted by desmodog

I have a used Traulsen URS-36-DT and the consenser fan does not seem to be behaving correctly. Essentially, it is always running, regardless of whether either of the compressors is running. I know this is not standard, but is it possible that it is designed that way for this unit? The other odd thing is that it only runs if both the refrigerator and freezer are switched on (at the switches, not the cold control). So I cannot turn the freezer off and have the condenser fan run for the refrigerator for instance. (Actually, I can, by turning off the freezer with the thermostat, but not with the switch). Is this wired incorrectly, or is there a part that is not working correctly?

Originally Posted by erik66

Pecmsg, I found this old thread about the condenser fans on a Traulsen. I have a URO DT36 with what sounds like a similar setup to the URS models. My freezer stopped working but I think its actually the fridge side compressor that is not working. At this point, I think the thermostat control is bad and I temporarily bipassed it to test the systems. I didi notice that the condenser fan only comes on when I energize the Freezer power but not on the fridge power. Any chance I can get that pdf of the wiring diagram to help me diagnose these issues?

It’s posted a few up.

Coogie

Originally Posted by pecmsg

This is the domestic model Traulsen, 2 compressors and 1 condenser.

There is a relay that brings on the fan if either switch is on.

I have a wiring diagram on PDF if you need it

Pecmsg, I found this old thread about the condenser fans on a Traulsen. I have a URO DT36 with what sounds like a similar setup to the URS models. My freezer stopped working but I think its actually the fridge side compressor that is not working. At this point, I think the thermostat control is bad and I temporarily bipassed it to test the systems. I didi notice that the condenser fan only comes on when I energize the Freezer power but not on the fridge power. Any chance I can get that pdf of the wiring diagram to help me diagnose these issues?

Thank you.

Attached. The (rather untidy) blue add-ins are for the relay I added to stop the condensor fan running when both compressors were off. Good luck.

Originally Posted by mxavierr

Could I possibly get the wiring diagram from you. Thank you

Manuel

Could I possibly get the wiring diagram from you. Thank you

Manuel

Originally Posted by pecmsg

This is a Traulsen design. At the time they were trying to compete with Sub-Zero for the residential market.

The first design used a static condenser mounted on the back with a 1” X 6” squirrel cage fan on a rheostat blowing from the top down. (Without the fan the compressors were over heating.) This same model had the freezer evaporator in the walls of the freezer. It was a lot of fun telling a customer that just paid 4g’s (mid 80’s $) that the freezer was a manual defrost. Along with the compressor noise issue this model was soon put to rest.

The new design used Tecumseh AE4440 & 4430 pumps (I believe) with a 2 circuit condenser coil-1 fan. These are not Tecumseh condensing unit’s just there compressors. Everything wrapped with insulating sheets to keep the noise down. (even they learned by there mistakes and did away with the in wall evaporator)Unfortunately they couldn’t compete with Sub-Zero and the others and the entire line was dropped.

Old man Traulsen, yes that was his name, started as a tech (mechanic as us old farts used to be called) and built the company. He took pride in seeing his name all over the world.
As a young mechanic I was sent to his apartment on 5th Ave in Manhattan. Getting off the service elevator there was no question which door was his. All Stainless Steel with the same Traulsen label.

There is no better manufactured piece of refrigeration equipment out there. Compressors, Fans, Controls etc will always fail but the Traulsen cabinets were built like a tank. I still see and service units 30 and 40 years young.

Cool story.

Thread closest to my problem: condenser fan runs constantly

Hi all: I'm hoping some of the solvers of the last issue with a similar can help me here. I have a URS48DT, and the way the condenser fan relay is wired, for the life of me I can't see how the fan is supposed to ever go off. Surely it is supposed to though, when neither compressor is runnign?

I have a wiring diagram Traulsen sent me for the UR48DT, and it correctly shows the relay coil energized by the thermostat. But my URS has such a different rats nest, I can't tell if it's supposed to be like that, or if it was wired wrong. I've tried trial-and-error swapping of the relay coil, NO and NC connectors, but the fan keeps running, independent of the thermostats being on or off.

a) There wouldn't be a relay if the fan on the URS was supposed to keep running, right?
b) Does anyone have a URS48DT wiring diagram?

Help?!

The relay problem is fixed -- it was simply wired backwards. Now the fan goes on whenever either side is on. I am still trying to figure out if it would screw things up to rewire it to run the condenser fan in line with the compressors. Otherwise, I might think about BLDC fan motors for this thing.

Thanks for the interesting history. You can still get the 48 inch version (now, the "Space Saver" line), although no longer with an ice maker. I don't think they can get them efficient enough to market them to the residential market, even though that is really what they were designed for.

This is a Traulsen design. At the time they were trying to compete with Sub-Zero for the residential market.

The first design used a static condenser mounted on the back with a 1” X 6” squirrel cage fan on a rheostat blowing from the top down. (Without the fan the compressors were over heating.) This same model had the freezer evaporator in the walls of the freezer. It was a lot of fun telling a customer that just paid 4g’s (mid 80’s $) that the freezer was a manual defrost. Along with the compressor noise issue this model was soon put to rest.

The new design used Tecumseh AE4440 & 4430 pumps (I believe) with a 2 circuit condenser coil-1 fan. These are not Tecumseh condensing unit’s just there compressors. Everything wrapped with insulating sheets to keep the noise down. (even they learned by there mistakes and did away with the in wall evaporator)Unfortunately they couldn’t compete with Sub-Zero and the others and the entire line was dropped.

Old man Traulsen, yes that was his name, started as a tech (mechanic as us old farts used to be called) and built the company. He took pride in seeing his name all over the world.
As a young mechanic I was sent to his apartment on 5th Ave in Manhattan. Getting off the service elevator there was no question which door was his. All Stainless Steel with the same Traulsen label.

There is no better manufactured piece of refrigeration equipment out there. Compressors, Fans, Controls etc will always fail but the Traulsen cabinets were built like a tank. I still see and service units 30 and 40 years young.

There is a heated consensate pan on the bottom of the unit. The condenser fan is on the top.

If the fan is wired to run all the time my guess is that your case has a non heated condensate pan and they are using the air flow off the condensor fan to speed the evaporation of the condensate. I have seen this in quite a few self contained cases.

There is nothing in the circuit but the master switches and the relay. It is a single condenser (and fan) with two compressors. It is designed to be built in, so the ventilation needs to be good. That said, it is a fifteen-year-old unit, and may simply be an older design less focused on efficiency.

It seems that it would be fairly straightforward to wire it so that the fan would only got on when one of the compressors did, but I don't want to do this if it is a bad idea. Does anyone know if the current UR48 models use the same design?

Originally Posted by kbghdg

Tell that to Silver King. Their condensor fans are wired to run 24/7. I think it might be planned obsolescence. You know the quicker the condensor gets packed with dirt. The more likely the cap tube gets plugged that leads to compressor failure. Or their just looking out for us service techs. Keeping us employed.

Wow...at our new lowered rate of 34 cents per Kw (4x what I paid in the states) that could also add up over time running those fans continuously. I wonder what they were thinking? It would be interesting to hear their engineer try and explain that one. Maybe they are thinking that most of the wear of the fan motor occurs at startup so just keep them running, but if that's the case then the planned obsolescence theory is out the window. Either way I don't like it.

Originally Posted by man from trane

Running the condenser fan without a compressor is pointless unless you're trying to get your electric bill up. Surely that cannot be what the engineer planned. Is there maybe a pressure switch in series with the fan set too low or stuck? Something is not right.

Tell that to Silver King. Their condensor fans are wired to run 24/7. I think it might be planned obsolescence. You know the quicker the condensor gets packed with dirt. The more likely the cap tube gets plugged that leads to compressor failure. Or their just looking out for us service techs. Keeping us employed.

Running the condenser fan without a compressor is pointless unless you're trying to get your electric bill up. Surely that cannot be what the engineer planned. Is there maybe a pressure switch in series with the fan set too low or stuck? Something is not right.

If this is a resadentle it is probly not a lot of air flow through condensor
I would keep it runing all the time
two compressor's one condensor and not much air flow

Any SPDT 110V coil relay will work. That’s a 9 or 16W motor.

If I understand the wiring diagram, the condenser fan does indeed run all of the time, although it should come on with either switch on, so I would guess there is something wrong with the relay. It is no big deal unless one side gets left on for a while with the other side off.