Coolant to coolant heat exchangers

[Ramdough]

All

I am contemplating on using a coolant to coolant heat exchanger to isolate my engine coolant water from my camper heater water.

I am not entirely convinced, but that could help prevent a leak or problem in the camper from causing the truck to have a problem.

I plan to have an Espar heater, under floor heating, cabin hot water, heated towel rack, and some heater cores running off of the camper hot coolant water. Should I isolate all of that from the engine?

What do you all think?

Thanks


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[jwiereng]

A bypass valve would allow you to isolate camper from truck in the event of a leak.

 

[Ramdough]

I planned that originally. For some reason, I remember a build that had the added heat exchanger.....I am trying to remember the logic behind it.


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[nick disjunkt]

It can be useful in campers if the height of the highest point in the camper heating system is above the header tank in the truck cooling system. If that is the case, unless you use two separate circuits connected by a heat exchanger, you'd have to raise the height of the header tank.

 

[Joe917]

It can be useful in campers if the height of the highest point in the camper heating system is above the header tank in the truck cooling system. If that is the case, unless you use two separate circuits connected by a heat exchanger, you'd have to raise the height of the header tank.

Both my radiators in the camper are higher than the truck's header tank, no issues.
I see no reason to separate the coolant in the camper from the engine coolant.

 

[fluffyprinceton]

I am trying to remember the logic behind it.

With a complex espar/multiple heating system there are many more leak possibilities - a bypass valve is one way to minimize that but you'd have to use it when parked unless you wanted to heat the engine block. It's the lowest cost option.

I went with a heat exchanger as it only added 4 more hose connections and seemed at the time a safer solution - I still wonder if combining the two systems would work from the engines point of view & it seemed too experimental at the time. I was worried I might get an air lock or excessive flow resistance given the length & complexity of the plumbing runs.

In practice bleeding the air out of the espar, radiant floor, H2O heater, expansion tank, engine heating loop and air heater was such a PITA that I'm very glad I didn't tie the engine cooling system into it. The heat exchanger in-line with the engine cooling system has a Johnson pump to run hot espar H2O through it - works great - in -10 deg F it heats the block to 70 deg F in under 30 minutes, makes for a happy diesel.Moe

 

[Ramdough]

With a complex espar/multiple heating system there are many more leak possibilities - a bypass valve is one way to minimize that but you'd have to use it when parked unless you wanted to heat the engine block. It's the lowest cost option.

I went with a heat exchanger as it only added 4 more hose connections and seemed at the time a safer solution - I still wonder if combining the two systems would work from the engines point of view & it seemed too experimental at the time. I was worried I might get an air lock or excessive flow resistance given the length & complexity of the plumbing runs.

In practice bleeding the air out of the espar, radiant floor, H2O heater, expansion tank, engine heating loop and air heater was such a PITA that I'm very glad I didn't tie the engine cooling system into it. The heat exchanger in-line with the engine cooling system has a Johnson pump to run hot espar H2O through it - works great - in -10 deg F it heats the block to 70 deg F in under 30 minutes, makes for a happy diesel.Moe

I knew there was a reason. It may be preference thing, but I will be in a similar boat with number of devices.

By chance do you have part numbers and sources? I would like to read up on them.


Thanks


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[Joe917]

You are wasting money with a coolant to coolant heat exchanger and adding an extra component to the system. You don't require a bypass valve. All you need is a shut off valve on one of the lines connected to the engine side of the coolant loop.
FWIW this is the set-up that has been run on my truck since 1993.

 

[Ramdough]

You are wasting money with a coolant to coolant heat exchanger and adding an extra component to the system. You don't require a bypass valve. All you need is a shut off valve on one of the lines connected to the engine side of the coolant loop.
FWIW this is the set-up that has been run on my truck since 1993.

Do you have a schematic?


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[Ramdough]

Here is a schematic from a truck that I saw once in Germany for reference of what I was looking at doing. Maybe simplifying my version.

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[Joe917]

I don't have it handy, and I'm on the road, Oklahoma headed to the 4 corners.
You "T" into the engine coolant loop according to Esparcher/Webasto.
Engine coolant runs to a "T" that meets camper coolant, this mixed coolant now goes through the Esparcher/Webasto to another "T" and returns to the engine and camper.
This creates two loops with the Espar/Webasto in the middle.
A shut off valve on either side of the engine loop connection will cut the engine coolant off.( put valves on both lines for maintenance or emergency, but you only have to close one in normal use)
Individual valves on radiators, underfloor heat etc control cabin temp.
This allows you any combination of heating you require.

 

[nick disjunkt]

Both my radiators in the camper are higher than the truck's header tank, no issues.
I see no reason to separate the coolant in the camper from the engine coolant.

How do you top up the coolant? Surely it will all flood out of the rad cap when you open it? Do you have a separate header tank in the camper which you fill the whole system from?

 

[Joe917]

How do you top up the coolant? Surely it will all flood out of the rad cap when you open it? Do you have a separate header tank in the camper which you fill the whole system from?

There is no header tank in the camper. The camper system was topped up from the top of the highest radiator.( bathroom rad added 4 years ago ).
I have had the truck coolant cap off without any leak issues but now you mention it I don't recall if the separator valve was closed. I initially had a small leak at the base of that radiator, but only when running Webasto heat in camper only. The leak stopped after a few weeks of use (it was a tiny drip in the wet room) and a few tentative tightens (I hate overtightening brass parts). The system is running fine with an air space in the top of the bathroom rad, I figure it id acting as a header tank for the camper.

 

[fluffyprinceton]

Joe 917 makes a good case for keeping the engine in the loop - the only caveat being I don't know how complex his system is. Doing so would save money and reduce overall system complexity but I'm not clear on how you would control (or the value of controlling...) the individual heating circuits - floor radiant,air heaters, domestic hot water engine pre-heat and whatever else...

Mine was like your included schematic with 4 circuits controlled via a manifold & the schematic also isolates the engine. I know in mine bleeding the system was really difficult and keeping the engine & house systems separate was a choice I am happy to have paid for. With my valving system I can run all the espar heated H2O individually wherever I want which is great for my needs. Moe



I used a Johnson CM10.
http://www.spxflow.com/en/assets/pdf/JP_CM10-30_461_02_01_2016-GB%20web.pdf
These look similar.
http://www.ebay.com/itm/BOSCH-AUTHENTIC-WATER-TO-AIR-INTERCOOLER-PUMP-0392022002-FORD-03-04-COBRA-SVT-/262523621209?hash=item3d1fa08f59:g:CAsAAOxycmBSvEw8&vxp=mtr

The heat exchangers were reconditioned ones off marine engines similar to this but a bit smaller & I don't think I paid much over $100.

http://www.ebay.com/itm/Westerbeke-W33-Heat-Exchanger-Very-Nice-Condition-/252660122289?hash=item3ad3b782b1:g:BKoAAOSwOyJX5~gL&vxp=mtr

 

[fluffyprinceton]

Another thought - With my multi-circuit system I'd be adding 30+ feet of hose, 2 radiators, 5 valves, 40ft of radient tubing, etc.- plus the espar to an engine cooling system that works fine as designed...I thought there was a decent chance adding all that stuff would screw it up...Too many unknowns so I took the sure thing...Moe