With colder weather coming, I'm reminded of the slow lag time between temperature adjustments and actually feeling the change. I have been considering installing a booster pump in the line from the engine to the dash heater. Has anyone done this or know of a pump that would work well for this?? Thank you and have a great day. ---- Fritz
The boost pump was standard on '91 U300's. Mine went out several years ago and I replaced it with the model MP-110 from TAC:
http://commerce1.cera.net/tacbusparts/sections/catalog/catalog.asp?cat_id=64 (http://commerce1.cera.net/tacbusparts/sections/catalog/catalog.asp?cat_id=64)
You might consider this: http://www.suremarineservice.com/906-089KIT.aspx?gclid=CL3GvoGgx7kCFexDMgody0oAuA (http://www.suremarineservice.com/906-089KIT.aspx?gclid=CL3GvoGgx7kCFexDMgody0oAuA). I found it while searching for a pump for the heater system.
I was thinking about seeing if the functionality of the motor aid water heater system could be reversed so that the propane water heater might keep the Cummins engine warm for easier starts in the winter. I figured that a 12VDC coolant pump might send heat from the water heater to the engine coolant.
What a clever idea to preheat engine coolant from propane water heater that has the coolant loop feature.
Looks like there are some ideas floating around on the topic:
Using a hot water tank/heater with a heat exchanger - Sprinter-Forum (http://sprinter-source.com/forum/showthread.php?t=1374)
John ---- On that U300, where did they mount it and how is it controlled? Is it forward in the dash, or in the rear engine comp't? Good to know that there was one installed on some coaches.
JD ---- Do you have a block heater and you would want to supplement that or in lieu of?? Might be alot of heat loss in that long loop and not very efficient. It would be interesting to see how well it worked, so if you do that, keep us all posted.
Thanks guys and have a great day ---- Fritz
Country Coach used to use 12 volt booster pumps for the coolant to the front heater. Some were mounted back by the engine and some were mounted up front under the floor behind the front cap, so guess they could be wherever would be convenient to mount them.
We do have a block heater. In temperatures below about 25F, we turn it on at bedtime if we plan to start the engine in the morning. It takes a long time to warm that big engine with a 4700+- BTU/hr electric heater. If dry camping (which we seldom do), I thought the motor aid loop might provide enough heat from the propane fired water heater to crank the engine without having to run the block heater and generator all night. The propane unit provides around 10,000 BTU/hr. Indeed, losses might be so great that the engine would get little heat. It would be an interesting experiment.
The conversation I saw on the Sprinter forum appeared to be a discussion about installing in the Sprinter a system like the three-way Atwood unit that was stock on our U295. I didn't see any discussion about sending heat to the engine from a propane fired unit. Perhaps I missed something.
Guess I'll know the answer better when I get a pump and know if it has a Net Positive Suction Head that will allow it to pull hot water from a longer distance. Seems like it would be OK to mount it up front since the NPSH from the existing water pump should be sufficient to provide ample inlet pressure. Guess we'll get one and mount it where best suited. Thanks and have a great day ---- Fritz
It's mounted in the rear next to the engine. I think Red Tractor is correct in that it could be any where in the hose circuit. I think there are two advantages to placing it in the back: 1. Closer to alternator and batteries. The dash area already seems to have a lot of amperage load on it. Pumps are a pretty good load and will draw down you dash voltage. 2. If your coach water heater has the Motor Aid feature, the pump will improve water heating - especially with the dash heat turned off.
The control switch is mounted on the dash with the label "AUX PUMP". I'm guessing the switch is controlling a relay but I would need to check. I can post photos of the pump if you like.
I actually tried it once in freezing conditions. I couldn't detect any change on my digital engine temperature gauge. I don't think much of that 10,000 BTU/hr gets out and what does gets lost on the way to the engine in freezing conditions. I was thinking for dry camping in cold weather that having multiple engine block heaters running simultaneously on the generator could do the trick in proportionally less time. My block seems to have an abundance of 3/4 NPT plugs on it and I can't help but think some would accommodate a heating element. Plenty of unused watts on the generator too. Would work too when you have hook ups and forget to turn the block heater on before going to bed.
They also had an insulated copper pipe in a track to make sure hot water ended up at the dash.
Bob
Would not expect a Cummins engine to require a pump to the front heater as Cummins have more water pressure than most engines., my ISM does not need a pump.
I have the heating feature for the hot water tank but I keep the valve from the heater line to the tank closed and send all of the water forward to the dash heater. Seems like I need the dash heater more that the hot water heater and I have an electric heater if needed. Thanks guys and have a great day ---- Fritz
Ah! I was hoping to get a reply from someone who had tried heating the engine with the water heater. Thank you for the reply. I will leave it alone.
My Foretravel was fitted with a rear Primus heating system as used by the Bluebird coaches.
It includes heat exchangers in the dash for heating that zone.
This is the pump that is used for the entire system. Its mounted behind 2 propane fired boilers near the engine.
http://www.dupreeproducts.com/SearchResults.asp?Cat=24 (http://www.dupreeproducts.com/SearchResults.asp?Cat=24)