Proheat Zones

[JohnEd]

On another recent post Charlie Davidson stated that "zone valves" were the KEY to having the Proheat system work.  I don't have a hot water heating system but it one of my dreams.  A nagging issue that I have not investigated is about the "series nature" of the plumbing.  I am a parallel kinda guy at heart and I like to turn on the part that needs it at the moment.  This is not a sexual pun of ANY sort.  The post recently that said that you need a strong pump to circulate the liquid fast enough so all the "radiators" have enuf on hand renewed my missgiving.  From what I gather, all the items that are being heated are in series and the area that needs the heat has its fan turned on.  To me that also means that on a cold start my living room won't get any heat till the water heater is warmed and the dash is cooking.  Or any combination of disappointments.  Lately I read that the engine heater must be "switched " out as it will heatsink your entire 45BTU in cold weather.  That part seemed OK and a manual valve being closed and another being opened didn't seem like a step back into the stone age in terms of having a sophisticated heating system.  I guess my question is : can this system have a pressurized "trunk line" or "manifold" line that the various elements and zones can draw from?  Zone valves?


I would have dropped this idea in a New York minute if it weren't for how many of you "pro's" without budget restrictions and those lesser endowed are quick to embrace it.  Only one complait have I heard and that guy is said to need a bigger pump to make "all well".  Amazing!  Not even a horse race here and this is the most expensive and labor intense part of a conversion.

Where can i get a look at a typical install that include a water heater and an engine heater and multiple zones of heat with floor and fan driven radiators?  I looked casually on line with the mfr.s and didn't come up with much.

Thanks, I think many would benefit from all your answers.  I know I will.

John

[Jerry Liebler]

John,
     I think a couple of things need attention to make hydronic series installation work well.  First the engine preheat heat exchanger should be a 'shell and tube' type and these can be installed to prevent the formation of a 'thermal siphon.'   Second using an 'aquastat' on the coolant return to control the fans pretty well eliminates cold blasts from un heated coils.   The heat transfer rate to the typical domestic water heater is so low it simply doesn't affect heating performance.  The series connection is much simpler and definitely more reliable. 
Regards
Jerry 4107-1120

[Songman]

This is something that interests me as well, and I have watched all the threads on it recently. My Hurricane is a little bit different than any of the others I have seen people using. I need to get a manual or something probably. I like the way Craig (gumpy) did his with the heating coils in the floor and walls, but also like the idea of being able to blow hot air out to heat the area faster.

I did find out that my Hurricane 45XL is a 61k BTU unit so with enough volume on pumps and enough valves, maybe I can make a split system of sorts.

I'm not sure I understand about the engine heater 'heatsinking' your unit. What does that mean?

[Jerry Liebler]

Songman,
     Regarding the engine preheat function taking all the heat.  If the heat exchanger to the engine's coolant isn't installed properly the fact that warm fluids rise can result in enough flow of the engine coolant that most of the boiler's heat output is taken by the engine coolant, leaving little or none for other heating. This unintended flow of engine coolant is called a thermal siphon.  Part of the cure is to install the heat exchanger above the engine.  Another part is using the proper heat exchanger and orienting it's ports to minimise convection induced circulation.
Regards
Jerry 4107 1120

[Ednj]

Try this again 

[JohnEd]

Ed,

Is the big square item in the top center right the hot water heater/exchanger/tank?  I have never seen this drawing before.  It seems to be using the fresh water supply to circulate and exchange the heat.  Can't I use the engine coolant to do this and keep my heating lines freeze proofed?  I think I could then delete the engine heat exchanger and add an exchanger for the domestic hot water....right?  I also thought that I needed a valve to isolate the "engine preheat circuit" from everything else when I wasn't using it.  Not true?

These were some pretty quick and detailed answers....thanks.

John

[JackConrad]

  Our system is a single loop with all the components connected in series using heavy duty heater hose.  Starting at the ProHeat, which is installed in the center bay, driver's side, a hose goes to the heat exchanger in the front bay, driver's side. The "other side" of the heat exchanger will be connected to the engine coolant via the OEM connection for the now removed OEM heater core. A circulating pump will be installed in this hose to pre-heat the engine. From the heat exchanger, a hose goes through the floor to the first heater core that is installed in the arm rest at the front of the sofa. This core blows into the driver's area. From this care a hose goes to a toe kick heater under the kitchen counter./ From this toe kick heater a hose goes to the flow though expansion/fill tank (towel warmer) in the linen closet (overflow from this tank goes to a plastic expansion tank). From the expansion/fill tank a hose goes to the bathroom toe kick unit. This hose has an Aquastat installed in it to prevent fans from running until water temperature is at least 120 degrees. From this toe kick heater a hose goes through the floor to the rear "water" bay heater. From this heater a hose returns to the ProHeat.
   If heat is needed when driving, the engine water pump is circulating "engine coolant" through the heat exchanger. Turning on the Proheat, the ProHeat circulating pump starts circulating the water that has been heated by the heat exchanger and allows the fans to run as soon as the circulating "ProHeat" water reaches 120 degrees. The ProHeat Boiler will not ignite unless water temp drops below 150 degrees.  Jack

PS: all exposed wiring in photo is low voltage (12 volt) wiring

[JackConrad]

   Here is a photo of the heat exchanger we installed in the front bay.  Fittings in the side of the heat exchanger are for the ProHeat.  Fittings in the end of the heat exchanger are for the engine coolant.  Jack

[Nick Badame Refrig/ACC]

Hi Jack,

Nice work!   I like that 2nd photo, it reminds me of a water chiller exchanger that I installed on a lobster tank a couple years ago.

Nick-

[captain ron]

Jack, I would personally think mixing water and electric together would be a bad thing. Just seems scary to me and I ain't skeerd of nutin.

[Songman]

Thanks Jerry. Sounds like I just need to make sure I have the right heat exchanger and have it mounted in the right place. I've got a lot of figuring to do before I actually start installing anything. The Hurricane just sits in my garage and I actually don't even know how the controls work on it.

[Jerry Liebler]

I tried to follow all of the instructions that came with my Webasto kit.  The results include my reservoir tank is the highest point in my system.  The reservoir tank flows down to the main pump which must be below the boiler.  The heat exchanger for engine heat is above the engine  coolant surge tank.  These constraints made for a bit of an equipment location challenge.  I solved the puzzle by locating the heat exchanger on the forward bulkhead of the engine compartment, above the transmission, the boiler on brackets from the same bulkhead but it is mounted to the rear of the heat exchanger.  The boilers brackets also mount the pumps.  The reservoir  I welded up out of polypropylene sheet and made it fit in the rear cap behind the right rear side window. The pictures show the boiler and the tank during construction.  Beyond that my system is  a single large loop that starts by going all the way forward along the right wall into the space between the original driver's level floor and the extended upper level where it goes into the domestic hot water heater.  The coolant out of the water heater goes to a 'summer/winter' valve which is a 3 way valve.  In the summer position the coolant returns directly to the reservoir tank via a hose along the left wall.   If the valve is in the winter position coolant flows through a large  (28,000BTU/h) fan coil also in the inter floor space.  This fan coil easily heats the driver's area and the front of the bus.  Coolant then flows along the left wall to 2 toe kick heaters under the kitchen counter and through a toe kick heater under the bathroom sink then to a toekick heater under the nightstand in the center of the rear, then to a small ducted heater under the front end of the right side bed and back to the reservoir.  All The Webasto lines are heavy duty heater hose.
Regards
Jerry 4107 1120

[Jerry Liebler]

A couple more details.  I do have a 120 degree aquastat in the 12 volt circuits for the fans.  The fans are in 2 groups controlled by two thermostats.  The forward thermostat is on the rear dinette wall and controls the big blower and the toe kicks under the kitchen counter (front of the bus) while the rear controls the fans in the bath and bedroom.  There is also an aquastat on the domestic water heater.  A 'diode' board electrically 'ors' the signals from the thermostats and the domestic hot water aquastat.  In the picture, previously posted, of the surge tank you also see the 'Perry' water filter and the electrical controls of the Webasto.   Frankly I found planning and executing this system to be the greatest challenge of the whole project.
Regards
Jerry 4107 1120

[captain ron]

No offense but I think some of you guys make this more rocket science than it needs to be. I agree that the planning takes a long time but for me it was more for keeping everything neat and compact. I was able to see the installs of several other units and learn from their mistakes and their great ideas and layouts.

[JohnEd]

Charlie,

I don't think anyone answered me on this:  Is there a serious down side to using the engine coolant for the hydronic system?  I see a lot of benifit in that methode right off the top.  Many have gone with a freshwater system and they are old pro's and I ponder that and my preferance.  In another post I think you indicated you would use engine coolant and you had looked at a number of other installs so you seem to be the man on this.   Got milk?

Thank you,

John