| Author | Message | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 52 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
I have an Espar diesel fired furnance and am considering the installation of it to replace my Suburban NS-40 forced air system. The Suburban works well enough but upgraded applicances by the previous owner blocked the original routing of two 4" ducts. Now I have no heat in the rear of the bus without considerable modification. The Espar system, I have is complete except for heat exchangers. I've looked at the Aqua-hot units which seem to be a good choice. So my question is how far can the hydronic heat be taken? Could I replace the original bus heat with an Espar/Webasto. The diesel fired systems seem to be a redundant application of the original bus heating system except the bus doesn't need to be running to get the benefit. Any input appreciated. Tom | ||
| Ross Carlisle (Rrc62)
Registered Member Username: Rrc62 Post Number: 166 Registered: 5-2005 Posted From: 67.142.130.16 Rating: N/A |
My Proheat runs through two baseboard zones and a heat exchanger for domestic hot water. It has kept the bus at 70F with outside air temps as cold as 10F. At those temps, the Proheat runs about 20 minutes per hour, which means it is not maxed out, which means it will handle colder temps. It works going down he road or sitting still, doesn't consume much DC and with the Proheat in the tank bay, it keeps that bay at above 50F. So yes, I would say that the hydronic furnace can replace the original bus system. It has in my bus. Ross | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 53 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
Ross, I see you've got a MC9. Did you upgrade your drivers heat/defroster exchanger when you put in the Proheat? The one in my 5 is noisey and not very efficient. Also what size system are you using BTU wise? thanks Tom | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 66 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Tom You did not mention the model Espar you have, but likely one in the 24 to 41 KBtu range. Typically 40K Btu should provide adequite for most peaple. Although trailers are being built in our neck of the woods now for use in the oilpatch, that have 2 40K propane furnaces. Think good for 40 below! For passive wetbaseboards the maximum lenght should not exceed 67 linear feet based on heatload of 40K 3/4" line. Also plan for the least no of elbows to keep flowrestriction to minimum. Joe. | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 54 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
Joe, The Espar system is a Hydronic 10. I believe haven't looked at it in over a year. Their 10 model is rated as 32,400 BTU/HR. I was thinking of using the Aqua-hot heat exchangers vise passive wetbaseboard. If this was new construction I'd work my layout around it, but since I must work with a completed interior the Aqua-hots will fit in the toe-kicks of my already established cabinetry. I hope. Each of the Aqua-hot exchangers are rated for 8k BTU with dual 12VDC muffin fans for circulation. Five are typical for most installations. 1 in the bedroom, 1 in bath and three in living room/kitchen area. Again that's my thoughts. One of my concerns is that if I expand my thinking to include replacing the driver's heater/defroster circuit and preheat the engine and make hotwater will the 32k be too small. Tom | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1798 Registered: 1-2001 Posted From: 75.108.79.170 Rating: N/A |
My 40k Webasto run everything that you are planning and at close to zero it never operated more than 50% of the time. I always left the hot water circulating thru the engine all the time and that probably accounted for at least 10-20% of the cycling. I do not think you would have a problem if your insulation is fairly decent. Richard | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 94 Registered: 10-2006 Posted From: 4.235.253.151 Rating: |
To lower the resistance of long runs try to get to the local refrigeration supply house, and ask for "slow Ell's". These have a 4 inch or so sweep instead of the sharp turn of the usual 90. Have you calculated the electric use of an Espar , and the circation pump and the extra juice used during each furnace light off? 48 hours with no "help" would be really nice. FF | ||
| Ross Carlisle (Rrc62)
Registered Member Username: Rrc62 Post Number: 167 Registered: 5-2005 Posted From: 67.142.130.33 Rating: N/A |
I have a 45K Proheat with 32 feet of baseboard. I did not upgrade the drivers defrost...yet. when I installed the Proheat, I added a fourth zone for the drivers defrost, just haven't done anything with it yet. I figured I'd get an after market heater unit to replace the factory one under the dash. I can go 4 days on batteries running the Proheat and the other house items that I usually run. Power sonsumtion will be much higher running toe kick heaters. Ross | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 56 Registered: 8-2006 Posted From: 207.231.81.154 Rating: N/A |
Fred is right, fast is good in hydronic flow as well as whatever Fred is fast at! What he is talking about is a "long radius 90," which has to be used in refrigeration, as Freon really doesn't like to go around sharp turns in a hurry. Water/glycol doesn't go around the sharp corners well either at the low pressures of the circulators used in all of the hydronic systems. For a reason I can't explain, we refrigeration people refer to tubing size by outside diameter, while plumbers refer to pipe size by inside diameter. So, a 3/4 copper 90 from Home Depot has to be ordered as a 7/8 long radius 90 from a refrigeration house. Likewise, 1/2 pipe is 5/8 in refrigeration terms, and 1 inch is 1 1/8. The beauty of hydronics is the ability to stash air handlers anywhere, with no gas or venting requirements, not to mention baseboards being silent and very energy efficient. You do have to run a pump, but if you used furnaces, you would have to run fans. The electricity consumed to light a pilotless hydronic, or a pilotless furnace is the same... Redundant,? think about this, 140,000BTU in a gallon of diesel, 10MPG at 60 MPH = 840,000 BTU/hour rejected via the exhaust and radiator(s)! Why not use it inside in the winter? Now, you also need to throw a whole lot of BTUs at a big windshield to keep it from freezing while driving in the winter. A heat exchanger for domestic water heat is mentioned above for good reason, not to mention your water is hot while driving, and when you get there, for free. Next is the problem of getting a cold Detroit to start, which isn't a problem with a hydronic plumbed into the bus heating system. I am a strong believer in keeping bus heat and defrost intact, after a friend removed it from a transit for bay space, and tried to get OTR heat from a propane furnace. It worked well parked, but the bus was a rolling tomb! | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 55 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
George, I agree with the idea of keeping the bus heat. The subject of removing the old OVTR system came up in a conversation with my wife. Used the example that it functions like the existing system without running the bus. Her response then was "why have two doing the same basic thing". That got expanded to look at all the extra room we'd have, if we removed it. Well, after twenty-five years together I could see the direction this was going and ended the convesation with "let me think about this". I've looked at PEX-AL-PEX for all the plumbing needs. They make a long sweep bracket specifically for the pipe to hold radiused 90's. As for DCV, looked at the numbers just after Fred's comments. Seems I'm going the wrong direction. My existing Suburban draws 7.5 amp to run the blowers. The Aqua-hot Cozy III fans use 6 watt/per unit @ 5 units = 30watts. At 12vdc = 2.5amps. The Espar Hydronic 10 has various flow setting but the worst case high output uses another 10.4 amps (boost position). So power wise replacing my 7.5 amp Forced air now would run me 14.0 amps off my 600amp house bank. One more comment on the defroster circuit, I need to improve on the 1965 design with hopefully a more modern approach. The unit is noisy with very little airflow and temped output. The gate valve is fully open, the hoses are intact, no leaks and plenum is sealed. The dual fan locations seem to be designed to pull air thru the exchanger vise blowing across then out. Just my thoughts. Tom | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 67 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Tom You are seeing now, whichever way you go with this, that ultimately it will still be a series of compromises. I am starting to lean in the direction of a standard Suburban furnace along with a Vented gravity heater of about 20K Btu, so that the vented heater, which would not be drawing any DC could be used for providing heat during moderate temperatures, with backup and supplemental heat coming from the furnace during colder temperatures. This way I would end up with about 60 K Btu and hopefully good for severe temperatures which we sometimes experience in this neck of the woods. The other factor to consider is the reliability. There have been enough posts on this board in regards to that. Now can anybody point me in the right direction to find a properly vented gravity heater ? Joe. | ||
| Nick Badame Refrigeration Co. (Dnick85)
Registered Member Username: Dnick85 Post Number: 80 Registered: 2-2006 Posted From: 66.174.79.240 Rating: |
George Todd is correct about the OTR Heat. Replacing the btus of the bus heat system would be great challenge. I would also advise you to keep the OTR A/C if possible for the same reasons. Good Luck Nick- | ||
| carl white (Carl_mci_9)
Registered Member Username: Carl_mci_9 Post Number: 2 Registered: 1-2007 Posted From: 24.154.148.105 Rating: N/A |
George: Did you tie into you bus hot water lines or did you run a parallel system from your engine? If you did use your existing water lines that run up front, how did you tie into them for inside heating? thanks carl | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 56 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
Carl, My plan for upgrading the MC5 heating was to run a parallel system from the engine using the old A\C piping that is still routed thru the bus. My A\C lines are located high on the firewall and run to the A\C compartment where they once connected to the condenser. I'm hoping to snake the PEX piping thru those pipes. Then route to system manifolds. For me using this available compartment gave me ready access to the burner, put the burner within required fuel pump distance and allowed for easy exhaust and air intake. That's the very basic plan. I can't see right now how to tap into the main system without going to the engine. I'd be interested in anyone elses approach. Tom | ||
| Ron Walker (Prevost82)
Registered Member Username: Prevost82 Post Number: 260 Registered: 11-2003 Posted From: 69.10.145.151 Rating: N/A |
I bought a hydro-hot from Vehicle Systems with all the PEX tubing - 6 heat exchangers, fittings, long radius bends for PEX, etc...came as a kit. Best purchase I'm made for the bus. No condensation in the winter or rainy months, the fans on thier heats exchangers are very quite...and give uot alot of heat.. Ron | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 57 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
Ron, Was it the Aqua-Hot 450-D or 600? I've looked at them on their website. They are very nicely designed. You got a source for parts/pricing. I can't seem to find one. I wanted to price the cozyIII exchangers. Thanks Tom | ||
| Ken Pridmore (Kenny)
Registered Member Username: Kenny Post Number: 3 Registered: 10-2006 Posted From: 24.180.252.90 Rating: N/A |
Using Webasto or other unit for heating and needing air for summer, would it be best to use the original bus heat exchanger/evporator and modify the ducting? Kenny | ||
| Tom Dessert (Mci5er)
Registered Member Username: Mci5er Post Number: 58 Registered: 12-2005 Posted From: 68.186.96.115 Rating: N/A |
kenny, I'm not sure if I understand your question. Could you elaborate on it a little for me? thanks Tom | ||
| Ken Pridmore (Kenny)
Registered Member Username: Kenny Post Number: 4 Registered: 10-2006 Posted From: 75.46.237.68 Rating: N/A |
I've got an MCI-9 in the slow process of converting. The bus has the original heating and cooling system. What about using the original system and make some air ducting modications to direct air to where it is needed based on the interior layout? | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 59 Registered: 8-2006 Posted From: 207.231.80.150 Rating: N/A |
Ken, Its not the slow process of converting, its the normal process of converting! Puns aside, the original bus air delivery system works well when you are a bus company in OTR service only. Look at the wall thickness of a bus between the windows and the floor... Half of that is air space, the other half is insulation, in other words, about 3/4 of an inch or less! So, use the original bus system, but cut the distribution ducts off before the walls, and install floor registers, or holes in the floor into the bottom of cabinets with narrow grilles in the toe kicks. The only caveat to this system is the fact that the heater blower motor, (also known as the evaporator motor) is 24 V DC. This means you will need a source for 24 V DC while shore powered or generating. Not an issue at all if you have a 24V inverter with 50 amps or more of battery charging, but a definite issue otherwise. Option 2 is to make this motor 120V AC, and run it off the inverter while on the road. With a Webasto or equivalent, you will have great central heat, the only negative being a relatively large electrical use when parked on batteries. | ||
| Ken Pridmore (Kenny)
Registered Member Username: Kenny Post Number: 5 Registered: 10-2006 Posted From: 24.180.252.90 Rating: N/A |
George Good point about large electrical use. I guess rather than using the original heat/cooling system, another option would be to use smaller satilite fan powered heat exchangers with a Webasto or similar water heating system. This would allow me to create heating zones and no duct work. But now what would I do for air conditioning ? Is there such a thing available as a central air conditioning compressor that could be plumbed to small satilite air exchangers ? Ken | ||
| Ross Carlisle (Rrc62)
Registered Member Username: Rrc62 Post Number: 168 Registered: 5-2005 Posted From: 67.142.130.49 Rating: N/A |
"the original bus air delivery system works well when you are a bus company in OTR service only." Another good point. How much time do you really spend rolling down the road. Unless your driving an entertainer for a band, a system that works better parked and works underway would be better. Original bus AC and heat sure won't work parked, but Webasto, Proheat, Aquahot, etc. and RV AC will work rolling down the road....and work well. For AC you have a few options. Rooftops with ceiling units are the simplest. If you want ducted AC, you can do ducted rooftops or if you want to sacrifice some bay space, basement units. Basement units are quieter but getting them repaired could be a problem. With rooftops, any RV shop can just install a new one if need be. I have 3 rooftops and have only ever needed two at one time. My front AC is in the front escape hatch hole and blasts a curtain of cold air down over the windshield. I have no desire for OTR AC. Ross |
