| Author | Message | ||
| Randy Davidson Rating: N/A |
Folks, I've got an 8V92 DDEC, Onan 12kw diesel gen, and Aqua-Hot. The basics are that the Aqua-Hot is designed to heat the engine block in cold weather for better starting. There are two very convenient 1-1/4" copper pipes coming from the DD that were used for bus heating (that I removed). I cut into these lines to attach to the Aqua-Hot. I've plans to continue these pipes (with appropriate ball valves) to the Onan to heat that block when parked in cold weather, too. The issues, not fully addressed in the archives, are: 1) can you direct connect two diesel engine coolant systems? A fellow named Jeff did it in 2001 with different equipment. Jim, in 2002, said it was not needed since the newer gen diesels don't start hard in cold weather. Vehicle Systems seems to agree with Jim. Anyone starting diesel gens in real cold weather? 2) should I just use a water-to-water heat exchanger instead and leave the gen system in tack (and within warranty)? I have a request in to Onan with no response yet. 3) if it IS a good idea to warm the gen block, does anyone know where or how to "cut in"? Thanks, Randy | ||
| jimmci9 #2 Rating: N/A |
not to discourage you, but several things need to be addressed.... you'll need a "burp' line to keep air pockets out of the generator system... the water to water heat exchager will require a circulation pump in the big engine circuit to make it work, unless you only run the generator when the big engine is running.... the detroit engine does best at about 170-180 degrees.. the smaller onan will want about 180....the cooling system on the bus is sized for the engine you presently have... any additional cooling demands might require a larger radiator....not to discourage you, 'cause i like the idea, but there's lots to consider here... | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
I have read a post in the past on one of the boards about a professional conversion being done that way. You might want something that can be remotely operated to separate the two systems. I read about a system in which the DD radiator was the only radiator in such a system. You will certainly have to be very careful to keep all of your hoses (and pipes) in perfect condition if you are going to put your engine in the system. No cheap heater hose or clamps in the system. My bus has all Gates Green Stripe (same a NAPA yellow stripe) heater hose at about $6 a foot in the for the coach space heating system. It has been there for about 22 years and is still OK. I have had standard auto heater hose burst in far less time in cars. | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hello Randy. With some careful thinking, shouldn't be a problem to get the three to work together in a complimentary fashion. It really will work well if you figure out how to get each piece to be the preheat for the others, depending on where and how you happen to be operating at which point in your trip through the cold weather. And then for efficiency, how to not heat the parts you don't need heated. Please share your design conclusions! happy coaching! buswarrior | ||
| R Swanson Rating: N/A |
Just an idea. If the Gen set is located away from the bus engine it may be easer to take heat from another heating zone circuit and divert it through a secondary circuit into the gen set, via a diverter valve. Diverter valves are available at any hydraulics shop. This would likley heat the gen engine to a starting temp in a few minutes and then heat could be restored to the primary circuit. | ||
| Jim (Jim_in_california)
Rating: N/A |
You know, this strikes me as a really astonishingly bad idea. Let's say, worst case scenario, your main drive engine's block cracks or something similar happens that catastrophically dumps coolant. And you're in Death Valley in the summer or someplace damned near as hot, plus you're off the beaten path some. Guess what? Your genset and AC are now hard-dead too. With completely separate cooling systems, the genset becomes a redundant source of power and you know...that can be what keeps you alive in a some situations... Maybe it's paranoid to treat certain systems as literally "life support connected" but...people still die in the desert when their vehicles break down. Not *often* mind but... | ||
| Vin (Billybonz)
Rating: N/A |
I'm NOT paranoid...I'm just very aware! This type of setup puts all yer eggs in one basket. I would want heat exchangers, more redundant. Same scenario with heat exchangers, leak in the DD cooling system, you might have enuff coolant in the other systems to get you back on the road after a quick patch and get you to town to get fixed right. Of course this could bite you in the a55 if the patch gives out and now you don't have enuff coolant to run any system. Perhaps I AM paranoid...never mind. Bones | ||
| Bill moldenhauer (Hotrodbill)
Rating: N/A |
The main difference between DD and generator is glow plugs in the genny I have the 12.5 and have started it in sub-zero weather with no problem. | ||
| Randy Davidson Rating: N/A |
I've not heard from Onan; but, if Bill says his starts in sub-zero with no problem because of glow plugs then I see no reason to gum up the works. BTW, if I were in Death Valley I wouldn't have the engines tied together for heat. Only if it were cold. But, I'm thinking this may be a mistake given the difference in 1993 DD 2 stroke tech and 2004 Onan 4 stroke tech engines. Probably will dump this idea and unsweat some copper joints. Thanks everyone, Randy | ||
| Jim (Jim_in_california)
Rating: N/A |
I have to think extra-carefully about such matters because as soon as possible I'll probably get a baby houseweasel (and raise it with a kitten). Ferrets *cannot* take high temps, they can die at temps up past 90degF and even 85 for a few hours can put 'em in heat-stroke. VERY inefficient cooling systems...their ancestors would retreat underground in case of heat so they can't even pant efficiently. They can get by with a tub of water and a fan for a while in a pinch, they're smart enough to dunk themselves and then blow-dry for cooling. But even that only goes so far... | ||
| truthhunter@shaw.ca
Rating: N/A |
Can't the ferret camp in the fridge in a emergency if it promises to save you a beer? | ||
| Jim (Jim_in_california)
Rating: N/A |
 Cute. | ||
| rbt137
Rating: N/A |
Randy: My 8V92 is extreemly reluctant to fire at 32 degrees. I spend considerable time at sno parks. My 7.0 KW powertech gen set coolent is parallel with the Webasto heating coolent. There is a 24V valve which determines which heat source is going to provide interior heat. during winter and in general, the gen set runs twice a day to charge batteries and deal with cooking....etc. The gen set radiator is completely covered. waste heat is pumped through the interior heating system. On rare occasions, it can become too warm and the roof vents will have to be opened to keep this system functional. The gen set is protected by a overtemp sensor and on rare occasions when I'm not paying attention, it has shut the gen set down. The only real problem I've experienced is that this system requires close supervision by the operator. This gen set has something of 800 hours on it and the 8v92 has some 50,000 miles on it. During summer months, the gen set radiator is unblocked and waste heat can be pushed outside either by opening the bay door or internal fans run off a thermostat. When this system was designed, another 24V valve connects the interior heating system to the 8v92. Either the Webasto or the gen set could provide heat to the 8v92 for starting. Also, when arriving, the coolent in the hot 8v92 can be pumped into the interior for upwards of an hour depending upon the outside temperatures. Again, this is a complicated system. Complicated systems are bad by their nature. On the other hand, this system has worked very well. In particular, it works well for me. Suit yourself and good luck. |