Bus Interior Heating Plan

Stormcloud · February 24, 2009, 05:07:30 PM

Theres almost no room in the water bay for theProHeat, and still be able to access it for maintenance.I have an odd shaped fresh tank to thank for that.

The reservoir should be likely always 100 degrees or warmer (even up to 180 degree cutoff of the ProHeat) so if the reservoir is side-by-side with the water tank, I thought I would have to worry about the fresh water being too hot from the radiant heat.

Mark

Brian Diehl · February 24, 2009, 05:21:00 PM

Quote from: Stormcloud on February 24, 2009, 05:07:30 PM
Theres almost no room in the water bay for theProHeat, and still be able to access it for maintenance.I have an odd shaped fresh tank to thank for that.

The reservoir should be likely always 100 degrees or warmer (even up to 180 degree cutoff of the ProHeat) so if the reservoir is side-by-side with the water tank, I thought I would have to worry about the fresh water being too hot from the radiant heat.

Mark

Mark, you should be fine in mild weather. However, I think the extreme cold and traveling at the same time will be a problem. Are you insulating the bay and the tank from the bay?

Stormcloud · February 24, 2009, 06:04:33 PM

Yup, lining the water bay with styrofoam insulation, and also insulating the reservoir tank. Maybe I should put a heater in there....just in case.

buswarrior · February 24, 2009, 07:38:38 PM

Something to consider..the boiler unit will need an ample supply of fresh air for combustion...There need to be holes for the exhaust to pass through, Unless you duct the unit, that means the bay has to be open to allow cold air in....

In sub zero, any air in will freeze whatever is nearby.

If you can pipe the intake and exhaust in and out and keep it sealed, good job!

happy coaching!
buswarrior

busshawg · February 25, 2009, 07:49:33 AM

Has anyone installed a small household 120V hot water tank in a bay and plumbed it into the webasto/proheat system. Just thinking, would it work to heat your system when pluged in ? and also would it work with the diesel heater? Could it replace the tank that Mark is thinking of fabricating for his basement bay?

busshawg · February 25, 2009, 09:11:27 AM

Just thinking if that was to work and whomever was traveling in the winter and the proheat/webasto goes for a crap a person would be able to run the gen set in an emergency to heat the water?

Lee Bradley · February 25, 2009, 09:17:27 AM

Quote from: Stormcloud on February 24, 2009, 04:49:47 PM
Thanks for the comments and advice. Keep it coming!!!!!

Bob (of the north) and I have discussed the heating system a few times. Since we live (sometimes ) in similar climates, he knows what will work and what will excel, based on his personal experience.

I've made a couple of alterations to the plan, namely the engine preheat will be included with the bedroom/bath loop and controlled by a few valves. I dont expect to use the engine preheat, since I have a block heater, but redundancy is not a bad thing and having the valves in the last bay under the bedroom near the engine seems to be a good spot.

The front bay (electrical) will have the ProHeat in it; close to the diesel tank and power.

The middle bay (freshwater) will hold the 5 gal reservoir, manifolds and pumps; residual heat loss should prevent the freshwater from freezing. Likely the marine hotwater tank will be here also.

The last bay presently holds a grey and a black tank. These are to be replaced by a single tank. This tank will sit on a piece of 1.5 inch styroam insulation in which a groove has been routered to accept the Pex pipe on the return from the bedroom/bath loop. This should keep that tank from freezing.

I'll run all the lines on the bottom side of the floor, and only pass through the floor for the heater connections.

The pumps I have are 1/25 Hp Grundfos pumps (120 volt though). This isnt a problem as we always have the inverter on, and also carry an backup inverter...

Too bad you already have those. The solar heat people have some great 12/24 volt pumps.

I'm a bit on the fence about the marine water heater, though.

Tell me more about the flat plate heat exchanger and how well they work; especially if you have had both, which do you prefer? The plan may change again.

I'm looking at the three way RV heater because it can use the heat from the engine/Proheat but you don't have to fire up them to get hot water during the summer.

Mark

PS: Grant...I didnt show it in the plan, but I will have a fill point and expansion tank in the bathroom, directly above the reservoir. Still got coffee on if you're in the area.

Lee...I considered using a hot water tank as the reservoir, but the element size is a concern. If I installed a 1500watt element, that can make quite a diffence in available power if Im plugged into a 30amp service. I think I would likely have the tank custom made (to fit the available space), and I'll foam insulate it when its completed/installed and no leaks. Thanks for the suggestion!

busshawg · February 25, 2009, 09:20:14 AM

duh, sorry, hec of an idea!

Sean · February 25, 2009, 10:51:00 AM

Quote from: busshawg on February 25, 2009, 07:49:33 AM
Has anyone installed a small household 120V hot water tank in a bay and plumbed it into the webasto/proheat system. Just thinking, would it work to heat your system when pluged in ? and also would it work with the diesel heater? Could it replace the tank that Mark is thinking of fabricating for his basement bay?

The "recovery rate" of most small 120-v DHWH units is too low to be effective to heat a hydronic loop. It would not be able to keep up. However, what you describe is the premise behind the AquaHot system -- in that system, the boiler, heat exchanger, and tank are all built into one unit, and there is an electric heating element immersed in the hydronic fluid. That element, though, is much higher output than ones found in DHWH units. This allows you to use the entire hydronic system while plugged in to shore power, without running the boiler.

For straight Webasto or Proheat installations, it's usually more cost effective to achieve electric backup outside of the hydronic system. For example, we have a marine HWH -- it has exchanger coils in it for the hydronic system, and also an electric element for use with shore or generator power. In addition to hydronic fan-coil toe-kick heaters, we also have electric toe-kick fan heaters. When we are plugged in, or running the genny, the hydronic system remains switched off.

There are pluses and minuses to each method. Having the electric element in the hydronic system means you don't need additional electric fan heaters or elements in the DHWH, which can simplify your coach layout. But it also means that a failure in the hydronic system, such as a pump impeller or coolant loss, will leave you without any heat or hot water at all. We prefer the redundancy of completely separate systems -- if the Webasto or pump craps out, we can still get heat and hot water by running the genny. Likewise, if the genny craps out, we can still get heat and electricity by running the main engine.

As always, everything is a compromise.

-Sean
http://ourodyssey.blogspot.com

busshawg · February 25, 2009, 11:35:02 AM

I don't mean to be taking this tread away from ya Mark, as you know the heating sytem is on my priority list for spring as well, all the info I can get the better off we are.

Has anyone ever tried installing a second element into a 120V hot water tank?

Stormcloud · February 25, 2009, 06:46:50 PM

Hi, Grant:

Its not hijacked....everything here is relevant and some good ideas are in here.

The 1500w heater element wont be enough, as Sean said. I have a 5000 watt heater element in a 5 gal hot water tank that is used to heat the fluid in the concrete floor of my 500 sq ft workshop. It works Great!

It would be possible to install a 2nd element in a small tank, but it would like destroy the glass lining of the steel tank, allowing rusting to start. Two 5kw elements in a tank could do an admirable job of heating the bus, but would require 80% of a 50amp 240 volt service, leaving not a lot for battery charging, frig, coffee maker, block heater, etc.

Mark