ProHeat Question

[Songman]

Good enough. Thanks!

[JackConrad]

     Researching circulating pumps on the internet, I came across this statement    Remember, a closed loop system with no air pockets is balanced and has no head requirement for pump except pipe friction.
     Does this mean my ProHeat closed system will pump the GPM @ 0 FT. listed on the pumps specs?  Jack

 

[missadventure]

Proheat as well as Webasto have there own pumps in the unit. Webasto has a highter volume pump in the higher btu units, Proheat does also. I've seen systems installed with a second pump at the for end of the loop for a booster, this pump is wired thru a realy tee'd off the main pump in the unit for power so it runs in parallel . The pump in the unit is readily available thru Proheat or Webasto suppliers. The second pump increases the flow and makes up the lift the to get the weight of the water up out of a cargo bay and flowing thru the system.

[gumpy]

     Researching circulating pumps on the internet, I came across this statement    Remember, a closed loop system with no air pockets is balanced and has no head requirement for pump except pipe friction.
     Does this mean my ProHeat closed system will pump the GPM @ 0 FT. listed on the pumps specs?  Jack

Yes. Once your lines are filled and all air has been removed, there is not head on the pump to push the fluid up into the coach, except
for negligent friction on the inside of the tube, and elbows, etc. you've installed in the lines. Your returns should come back into the system
below the level of the tank, so no air can be sucked into the lines.

craig

[Ednj]

>

My liquid returns to the top of the tank, which has 8 gallons in it.
The proheat pump is strong enough to circulate the whole system and push out the air.
I have 3 zones working, the flat plate exchanger is the shortest path with the least resistance always open and the proheat pump can keep up no problem.

[gumpy]

My system is vented open to atmosphere.
The tank is not the highest point.
When the system is off all liquid returns to the tank.
I don't know about a pressure cap.

That's why the larger gpm pump and the thermostatic controlled zone valves.

Right, if your lines can drain back to the tank, and suck air back into the line, then you will need to take the head into account as the pump has to push against the air in the lines and push the weight of the fluid.

If your lines begin and end below the level of the tank fluid, and you remove all the air either by pumping fluid through, or sucking the air out as you fill, then you don't have to worry about the head pressures.

The tank does not need to be the highest point in the system. You just have to have the lines begin and end below the fluid level in the tank. If you can't get air into the lines, then the fluid cannot drain back to the tank. Pressure cap doesn't have anything to do with the drain back. Drain back is controlled by the level of the fluid in the tank in relation to the lines coming into it. The pressure cap and reservoir are used to keep air out of the system, which causes corrosion of steel parts in the system, and allows for expansion of the fluid as it heats.

[gr8njt]

FWIW, I used a $15 automotive coolant reservoir from Pep Boys.
"Tee'd" before the Proheat pump and mounted at the highest point of the Proheat Loop inconspicously inside the coach.


By nature, air rises to the highest point. Air then escapes into the reservoir (into the atmosphere) and is replaced with coolant (by gravity) of the same volume.  My Proheat is running flawless since and completely eliminated the "coolant errors" I used to get. Additional advantage I realized is that the reservoir acts as an expansion tank and coolant refill point.

Hope this helps.

[Ednj]

Hi Ray,
All of us who frequent Delaware have pretty much the same system set up,

[Nick Badame Refrig/ACC]

Oh Ed...

Not all of us who frequent Delaware do it the same way..

Me and Ray are oddballs   lol

Nick-

[NewbeeMC9]

FWIW, I used a $15 automotive coolant reservoir from Pep Boys.
"Tee'd" before the Proheat pump and mounted at the highest point of the Proheat Loop.

By nature, air rises to the highest point. Air then escapes into the reservoir (into the atmosphere) and is replaced with coolant (by gravity) of the same volume.  My Proheat is running flawless since and completely eliminated the "coolant errors" I used to get. Additional advantage I realized is that the reservoir acts as an expansion tank and coolant refill point.

Hope this helps.

gr8njt I like your set up and thanks for the schematic!

Did you use hose clamps and the brass pex fittings in stead buying the pricey crimping ring tool?

Also, did you say previously that you WH/resivoir had a second coil in it that u use for engine heating, does it also work for heating with the engine running?  If so how does it circulate when using engine for heating mode?


I saw you have the load's in parralel to each other and the rest in series.  is that how most of you guys are doing it?

Also,another question out to the crowd.  has any body thought about using Llight oil as the fluid in your system?  it has a lot better heat carrying capacity than antifreeze mix.


thanks to all since were on the subject and striking for an article here.

[gr8njt]

gr8njt I like your set up and thanks for the schematic!
1. Did you use hose clamps and the brass pex fittings in stead buying the pricey crimping ring tool?
2. Also, did you say previously that you WH/resivoir had a second coil in it that u use for engine heating, does it also work for heating with the engine running?  If so how does it circulate when using engine for heating mode?
3. I saw you have the load's in parralel to each other and the rest in series.  is that how most of you guys are doing it?
4. Also,another question out to the crowd.  has any body thought about using Llight oil as the fluid in your system?  it has a lot better heat carrying capacity than antifreeze mix.
thanks to all since were on the subject and striking for an article here.

NewBee,
I'm glad the schematic helped.
1. I used brass Pex fitting and Pex cinch SS rings in my set-up
2. The HW tank I'm using is a "Marine" type HWH. I plumbed it so as to utilize it as the Proheat's storage tank. It has factory (a) 110vac heating coil and (b) a coolant heating element which can heat the tank content when the bus engine is running OR vice versa - - to warm the bus engine (using a "free wheeling" auxillary pump) when cold for easier starts. Another possible option is to tap this coolant coil to your generator cooling system to get free heat when Gen-Set is on.
3. The schematic above is how I did my Proheat system since I'm using residential type heating manifolds. I prefer such set up so I can control each loop independently from one another. First loop is for the "Flat Plate Heat Exchanger" which is kept always open. Like Ednj said, most of the Delaware gang have similar set-up in one form or another. The other good news is that they're all proven to work in our individual buses!
4. I do not know if "light oil" will work with the Proheat pump. However, FWIW, I use "Cryo-Tek-100" anti-freeze specific for hydronic heating and purchased from Home-Depot. Advertised as non-toxic, circulator pumpable to -60F, corrosion resistant and safe to use with rubber and most plastic components.

Good Luck.

[gr8njt]

Me and Ray are oddballs   lol
Nick-

BTW, the idea to use an automotive coolant reservoir was copied from the the original.... YOU!!         which makes me only a backup oddball.  LOL
But hey, bottomline and seriously speaking.......IT WORKS!!!

[donnreeves]

With all this talk about storage tanks in the system to cut down on the cycle times, I decided to add one. I installed a 5 gallon tank in-line and am diapointed with the results. Before the addition of the tank, the Pro-Heat would reach shutoff temp in five minutes from a cold start. once the bus was up to temp it would cycle every 20 minutes and burn for three minutes. Now with the tank, it takes almost 20 minutes to reach shutoff temp, cycles every 20 minutes and burns for 3.5 minutes. Seems like I went backwards. My system already held 4-5 gallons and has an Extrol bladder type expansion tank, so I don't think the extra volume is doing me any good. I'm going to remove it. Like Jack, I pump the coolant into the system, and can bleed each zone with the fill pump. My PH pump easily handles the circulation chores, and I have never had any problems with air, do to the pressure fill and bleed system I use.  Donn

[gr8njt]

With all this talk about storage tanks in the system to cut down on the cycle times, I decided to add one. I installed a 5 gallon tank in-line and am diapointed with the results. Before the addition of the tank, the Pro-Heat would reach shutoff temp in five minutes from a cold start. once the bus was up to temp it would cycle every 20 minutes and burn for three minutes. Now with the tank, it takes almost 20 minutes to reach shutoff temp, cycles every 20 minutes and burns for 3.5 minutes. Seems like I went backwards. My system already held 4-5 gallons and has an Extrol bladder type expansion tank, so I don't think the extra volume is doing me any good. I'm going to remove it. Like Jack, I pump the coolant into the system, and can bleed each zone with the fill pump. My PH pump easily handles the circulation chores, and I have never had any problems with air, do to the pressure fill and bleed system I use.  Donn

You're right on the money Donn. Stay with your original 4-5 gallons + expansion tank.
A total of 10+ gallons of coolant within the Proheat loop maybe an overkill.

The Proheat service manual indicates on page 58, Coolant section (f) "The coolant system must contain at least 3 gallons  of coolant. If the system contains less, it may heat up in less than a minute causing 'coolant flow error'."

Analysis of the above service manual section clearly states that the use of less coolant causes rapid heating in a very short period. Therefore, the opposite is implied, that use of more coolant causes slower heating in a longer period. No wonder you increased the time to reach shut-off temperature of 180F.

IMHO, 4-5 gallons is the magic volume to give allowance for incidental coolant loss during operation.
One reason I'm staying with my 5 gal Marine HWH tank.
Keep us posted with the outcome of the switch back.

.