[HoosierDaddy]

http://www.climaterightair.com/

[Flick]

Are you thinking of something like this for cooling maybe a storage trailer that is pulled behind an RV?

[HoosierDaddy]

I'm ruminating on the options available that would supply heat and cooling to my dashboard ducts. From what I can gather they seem to be heat pumps. I'm wondering if the components are same/similar to RV roof top mount heat pumps. If I were setting up an enclosed trailer my first choice would be a roof top unit but if that is not possible the 13,500 btu stand alone unit might work fine.

[77newell]

It could work though it's not straightforward. Given the 31in height it will take some revision to place it under the dash. Tipping it on its side would require redesigning the condensate drain system. How the guts of the unit are arranged will determine the effort required to do this.

The other issue to consider is heat output. Dash heat in my 93 is abysmal, worse than the 77 of all things. Ostensibly based on core size and water temperature it should produce 35,000btu per hour, that it doesn't seem close to that is a problem for another post. For here and now the issue is that the proposed unit puts out about a third of the original. That could be fine depending on when and where travel occurs, then again your kishkas (Yiddish innards) could freeze. I like my kishkas warming at a minimum.

I applaud the effort to improve the performance of the dash HVAC. Given how pathetic mine is I too am searching for a better solution.

[encantotom]

that thing does not have enough btu's to cool the front of the coach in my opinion.

tom

[Richard]

For what it's worth, The 95 I had, 390, had fantastic heat with the dash unit. The 99, 512, has lukewarm dash heat. Also, the 95 would heat the AH during cold weather drives to above 150, the 99 struggles to heat the AH above 120 in cold weather driving.

The difference? The 95 had a circulation pump that boosted the water flow through the manifold that sends coolant forward to the dash, and to the AH. There was a micro switch on the heater controls that turned the pump on when the heat control was all the way to hot.

This may not be the whole story, but it's the limited data I have.

[77newell]

My 77 (not mine now) and the 93 both have boost pumps. On the 93 even though the boost pump appears to be hooked up to boost the flow already happening from the engine pump, when the engine speeds up from idle the air temp out of the dash vents drops. I have triple checked the flows and everything is according to hoyle, but it works terrible. There is full temp water coming into the heater core but little is experienced out the air vents.

When I asked the current owner of the 77 how the boost pump was configured, it is pushing backwards. I don't get how that heater can work better than my 93. I installed the pump in the 77, and I didn't know what I was doing. I guess ignorance really is bliss, or warmth as the case may be.

[ccjohnson]

Jon,
Is there any possibility that an air plenum (blend for hot & cold air off heater core & ac evaporator) is stuck or sticking? We had poor air flow on our dash system due to a blower motor being bad. I replaced all 3 blower motors while i was at it. Motors were less costly than regrowing knuckle skin so I just did all while I had it apart. Air flow is better now, but temp can be lacking in cold weather. We just run generator and keep electric heaters on while traveling in cold weather. Also, keeping side windows covered with blinds/drapes is a major improvement when driving in cold weather to keep inside nice & warm.

[77newell]

I've had the heater guts all apart a couple time. There are a couple weaknesses in my setup; the steel shell has no insulation so the greater the temperature differential between inside and outside the more transfer there will be, and the construction of the heater box and how it is fit into the coach is hugely prone to air leaks. I closed the door and windows and then turned on both the Fantastic fan and the stove vent fan on "high". Using an incense stick I followed the smoke train backwards and found that the penetration where all my hoses from the heater box came through the floor was leaking air, lots of it. From both above and below I crammed soft foam into the gaps until I could no longer detect air leakage. I also added a foam pad to the curb side of the heater box and positioned it to minimize outside air leakage. When I smoke checked the windows I was surprised to find very little leakage. These windows cover a lot of area so adding some insulation will help, I want to find something that lets light in so I don't feel I'm occupying a cave, two layers of bubble wrap perhaps. Another leak I found was coming from the bottom of the fridge, easily sealed. One other spot was the entry door sealing - which until I rebuilt my door was a half in gap in places and now the smoke test shows no leak.

Unless air leakage is virtually eliminated there is unlikely to be any heater that can keep up. When the heat load is reduced to just conduction and convection then we can consider insulation and/or increasing the heat input. I refuse to let the Prevost coaches win this one with better heat, they prove it can be done and we need to figure out how we will do it.

[DogKnots]

Interestingly ours heats the AH well above 150 but doesn't provide dash / cabin heat well.
I haven't really investigated it...we just work around it by staying in warm places!