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your APU input please

Skyline

Expert Expediter
Owner/Operator
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A new Thermoking Tripac for $9975 (installed) or a used unit with 5000 hours for $5500 (installed) with no warranty. Or maybe a slightly used Onan diesel 7500 watt with a rooftop AC and new Espar bunk heater, but what about engine heating? How adequate is an oil pan heater V. Water flow from APU for engine heating. What about diesel efficiency? Knowing that there are many knowledgeable owners and drivers on this forum, I would appreciate your input. Must get this done ASAP. Thank you and happy holidays to all.
Lenny
Fedex Custom Critical
Four Star Award 2011
DA7823
 

Slacktide

Seasoned Expediter
Offline
A new Thermoking Tripac for $9975 (installed) or a used unit with 5000 hours for $5500 (installed) with no warranty. Or maybe a slightly used Onan diesel 7500 watt with a rooftop AC and new Espar bunk heater, but what about engine heating? How adequate is an oil pan heater V. Water flow from APU for engine heating. What about diesel efficiency? Knowing that there are many knowledgeable owners and drivers on this forum, I would appreciate your input. Must get this done ASAP. Thank you and happy holidays to all.
Lenny
Fedex Custom Critical
Four Star Award 2011
DA7823

Skyline,

I have had experience with both units you are contemplating so here is my opinion/recomendation.

First on the Tripack they are a workhorse in my opinion, I would use one again if I were in an OEM sleeper. I dont know what size your sleeper is or the BTU output of the units you are looking at but in my opinion tripacks are best suited to sleepers up to about 84". The one I had used a loop system for cooling/heating and we didn't have any issues, that being said it did concern me some that if I did have a leak I would not be able to use either the APU or the main engine. For the $4500 savings between the new and used I would probably go for the used one, $4500 can cover quite a few repairs that may crop up. Note if you do decide to go with the used one I would have them install a new water pump and belts on the unit at the time of install being those would be the likely first failures.

The 7.5 Onan is what I have now and we have had ZERO issues with this unit, it provides all the power we could ever use. We have overhead air, apt size fridge/freezer, webasto bunk heater, electric hot water heater and a microwave/convection oven and two TV's. We could run everything at once and have power to spare with this unit. The other pluss is it is a complete stand alone unit and isn't dependant on the main engine for anything other than the starting batteries. You could give it it's own starting battery if you wanted. as for being able to preheat the main engine with the Onan we have a block heater that runs off the Onan via a switch in the sleeper.

If the price is right I would go with the Onan as my first choice and the Tripack as my second choice.

Depending on your inverter choice you may be able to have shore power as well. This comes in handy when at home you can plug it in and the generator wont run, also useful if you decide to utilize campgrounds or RV parks they tend to have "quiet hours" and frown on your generator of choice starting through the night. We have a magnum inverter with ours, not sure of the model/size I would have to look.

Good Luck in what ever you decide.
 

layoutshooter

Veteran Expediter
Retired Expediter
Offline
Running your APU through you truck cooling system is a double edged sword. It does keep your truck engine warm, when it is running. When the APU or the lines to and from it leak, you lose coolant from the truck. The plumbing can be a nightmare. Leaks are often difficult to find.
 

Skyline

Expert Expediter
Owner/Operator
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Excellent feedback. Points taken. My sleeper is only 84"and I have always been solo, so one TV will do! Ha. Just came out of Quebec again and it is lots of fun with no apu! Thanks
Lenny
(Must drive - kids eat ferociously)
 

Rocketman

Veteran Expediter
Offline
If money is an issue, you could have an Espar installed now, then start saving for the Onan and roof air.

The Tripac is imo the best APU. It comes with an Espar for heat. It does seem though, that those who have the Onan/rooftop setup are the most satisfied with their purchase.
 

Skyline

Expert Expediter
Owner/Operator
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I was considering waiting, but I saved for a new unit, so I might as well go ahead and do it all at the same time. Will take a final look at the Onan before deciding. Would I have to install the Onan in a cabinet or just straight on brackets to the chassis?
 

Slacktide

Seasoned Expediter
Offline
I was considering waiting, but I saved for a new unit, so I might as well go ahead and do it all at the same time. Will take a final look at the Onan before deciding. Would I have to install the Onan in a cabinet or just straight on brackets to the chassis?

Every onan I have seen has had some sort of cover installed. The covers are just one more layer of protection for your investment, they keep most of the road grime and salt off of the unit while traveling. The installers should be able to tell you if you actually "need" it but I for one would highly recomend that you get it if that is how you decide to go.
 

rfields200

Seasoned Expediter
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The Tri-Pac can be installed without connecting to the trucks cooling system. That is the way it was done until they came out with the Arctic switch to keep the engine warm. I have a shut-off valve installed in each line on mine so I can seperate the engine and APU if there is a leak.
 

layoutshooter

Veteran Expediter
Retired Expediter
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The Tri-Pac can be installed without connecting to the trucks cooling system. That is the way it was done until they came out with the Arctic switch to keep the engine warm. I have a shut-off valve installed in each line on mine so I can seperate the engine and APU if there is a leak.

I too have shutoffs on my lines. One of them leaked. LOL! What a pain.
 

layoutshooter

Veteran Expediter
Retired Expediter
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The Tri-Pac can be installed without connecting to the trucks cooling system. That is the way it was done until they came out with the Arctic switch to keep the engine warm. I have a shut-off valve installed in each line on mine so I can seperate the engine and APU if there is a leak.

I too have shutoffs on my lines. One of them leaked. LOL! What a pain.
 

greg334

Veteran Expediter
Offline
5000 hours is a lot. Unless there is a record of maintaince that goes along with it, I would think that the worth is about 3000 at most. Many APUs have had some electrical issue and sometimes the logic boards are replaced, which means the hours are different than the actual ones. The ones with the hobbs meter are also suspect, I've replaced or repaired a dozen of them at one time or another.

As for coolant systems being hooked up together, that's all good and well if it is done right and throughout the past 5 years, I have seen only a handful done right where if there are issues, the APU can be isolated and the truck continue to run.
 

layoutshooter

Veteran Expediter
Retired Expediter
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Being able to isolate the APU from the truck protects the truck. I have used my shut offs to do that. It works. The problem is then that APU cannot be used. If I ever replace my APU, which I would love to do if I could afford it, I would not tie it into the trucks cooling system.
 

greg334

Veteran Expediter
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Being able to isolate the APU from the truck protects the truck. I have used my shut offs to do that. It works. The problem is then that APU cannot be used. If I ever replace my APU, which I would love to do if I could afford it, I would not tie it into the trucks cooling system.

There isn't a problem, can be done really easily and anyone with a grade school education who works on them knows exactly how to do it.

I have found having my tractor's APU serviced by the "factory authorized" people a bit scary when it comes to thinking and applying knowledge. I had all the lines changed when we got the tractor (didn't want to go through what you went through) and specifically told the tech I wanted to isolate the truck and APU separately, even gave him an idea how to do it. So after 7 hours of waiting I went to pick it up, asked the manager how does the new system work. The manager gave me an odd look and asked what I was talking about and I went through explaining it to him. He said that's too complicated and won't work but the parts and the labor for the change was on the bill and I told the manager that paying for something that wasn't done was too complicated.
 

davekc

Senior Moderator
Staff member
Fleet Owner
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If you do your own maintenance I would go with the Onan. If not, go with a Tri-Pak. Onan can be difficult to get worked one. Many places work on them, but can't get to you right away. Had one go out in Houston and out of 10 dealers, none could work it in for roughly a week. Oil changes the same problem. Some places ok, and other are totally lost. Like Speedco.
 

greg334

Veteran Expediter
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I don't understand. Are you talking about adding a cooling system for the APU? :confused:

Sorry, I will try to draw something up and post it.

BUT until then, here is what I wanted.

I wanted to have both systems to operate independently but have the option to have the APU heat the truck and fuel tanks if I needed to. I have two lines from the APU to the truck engine, I wanted to take those two lines and splice a valve into each of them and add a third valve on the APU side of the new valves in order to have the APU run. So here is what the summer time brings - heat that is not needed - so I shut the two valves from the APU to the truck and open the valve in between those other valves. The coolant flows through the APU radiator as it always has and the APU is isolated from the truck.

Now I did do this, I bought HP stainless ball valves ($10 each) and installed them as I just described.

Hope that explains it?
 

layoutshooter

Veteran Expediter
Retired Expediter
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Adding a radiator to my APU would likely be expensive, would it not? Might be cheaper to build a system like yours only if and when I buy a new one.
 

greg334

Veteran Expediter
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What?

Both of mine have them, they are cheap, I think the replacement cost was something like $175.

if you need one, it isn't hard to put on. Most of the engines use a 1 or a 1 1/4 inch hose and routing the hose to the radiator is nothing.

There isn't one APU out on the market that is complicated enough not to modify or set up right.
 

layoutshooter

Veteran Expediter
Retired Expediter
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What?

Both of mine have them, they are cheap, I think the replacement cost was something like $175.

if you need one, it isn't hard to put on. Most of the engines use a 1 or a 1 1/4 inch hose and routing the hose to the radiator is nothing.

There isn't one APU out on the market that is complicated enough not to modify or set up right.

I just thought it might cost more than that. Mine has none. I just hate to put ANY money into it. I might look into that. It would eliminate some of the problems I deal with.
 

greg334

Veteran Expediter
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Hey no problem, even some of the surplus companies have the radiators for under 100. I think the model that I need is one from a Bobcat.

I should have taken pictures of the work we did, the valves I got from eBay and tested them at 1000 psi (they are rated for 2000 psi).

I was thinking about if you don't have a radiator, using a radiator and an electric fan that can be mounted off the apu would work so when you are idling, the fan pulls air through the APU.

Again so much can be done, mainly because out of the 10 or so different APUs I have looked at, not one of them has a custom engine built by the APU company.
 
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