[Fulltiming]

There are friction losses in the long run of hose to the front so the heated coolant will take the path of least resistance through the shorter paths and reduced flow will occur in the long hoses. The long hose runs also provide an opportunity for more heat loss on the journey to the front and, at least in my Newell, those hoses are not insulated.

[qcj]

That might be true Michael, but I have no pump and I'm not having any problem with the AH or the dash heater not getting up to proper temp. I have changed my coolant and the large hoses and the 4 cut-off valves and run new hoses from the engine to the cut-off valves. The long hoses from the cut-off valves to the AH and to the dash heater I did not change. But these long hoses also run through heated compartments most of the way and the AH hoses are fairly short. Only two bays in front of drive wheels. After a days trip in cold weather the AH temp. gauge reads around 160 to 170 when we stop for the night. Not near as hot as it is when diesel is cut on, then it is 200 degrees, and on electric it will go to 210 degrees.
Don't get me wrong, I'm not saying you are not correct because you have been at this longer than I have. Merry Christmas

[lbrachfe]

I get the same readings as Chappell and MERRY CHRISTMAS , HAPPY HANUKAH and a Healthy Newell Year to ALL

[Richard]

Thanks for all your input and data. Rudy may be the closest to describing what I suspected. When running the coach heat, the AH temp will run around 120 to 130. I just don't think the coolant pump is circulating the enough flow to keep the AH warm. The engine temp is running around 200 as it should. In the warmer months the AH will read around 175 to 180.

Gordon, thanks for that info. Curiously enough the temp in the AH will climb 30 degrees if I turn on the preheat pump. Another clue that the circ rate from the water pump is not enough.

Yes, it could be a blockage in the cutoff valves. I will check that out.

Chappel, it is easy to associate the pressure in the system with differential pressure to move fluid or air from one place to another. The pressure on the radiator cap is static pressure, not differential pressure.

So, what I am hearing is that somewhere between coach 390 and 512, Newell stopped equipping the loop with an auxiliary pump.

[Dmatz]

Chappell

Pressure is the same throughout the system. Pressure does not create flow. You need a pump to move the fluid. These are closed systems.

[qcj]

O.K. so I was wrong to make that statement. But the engine does have a pump that moves the coolant, and there are two hoses connected to the engine so that one carries the flow to the heater and one to flow back to the engine. I'm sure that they are placed on the engine so they will best work that way. On my 07 with a Cat. engine it did not have a separate pump either and the heater worked fine. All I am saying is that as of now (I don't want to say never) I'm not having problems with engine coolant reaching the heater or the AH. Knowing Richard he will find out if he has a problem and he will correct it. I'm sure of that.

[lbrachfe]

Ditto what Chappell said and agree Richard needs us less than the forum needs him....Ha

[Richard]

So today, I went for a little cruise. Outside temp a balmy 38 degrees. AH temp comes up to around 170, however the coach heat is only set to 50, my storage temp. That confirms for me that there is some flow, just not enough. I haven't checked the valves yet.

[Dmatz]

Chappell

Pressure is the same throughout the system. Pressure does not create flow. You need a pump to move the fluid. These are closed systems.

[encantotom]

i have a leak in my heater core, so i plan on shutting off the coolant to the dash and use just my aquahot. the aquahot system has two ducts from the front plenum that goes to the defroster and i have 2 aquahot units up front at the driver and passenger ankles.

that is why i have interest in the valves chappel replaced becasue i have to replace those valves to be able to shut them off.

chappel, you didnt try to source them from other than newell? you said 160 apiece. did you mean for all 4 valves? even that sounds high if they were 160 for all 4.

tom