happybuy diesel air heater

[Iceni John]

The front one has a lot more work to do. The windshield is a large area to heat. If I keep the insulation panels up it is fine, but if I remove them to look out it is just not enough. I may install another one under the dash some day.

Be careful if you use a CDH as a windshield defroster.   A couple with a skoolie did that, and the heat cracked their windshield.   No bueno.

John

[buswarrior]

The optional bathroom water tank, behind the mirror, would make a lovely day tank, vent back to the fuel tank, pump to refill until you here the splashing.

Happy coaching!
Buswarrior

[Jim Blackwood]

No big deal my tool bags needed to be soaked in kerosene anyway. :-)

LMAO! Got to keep your tool lubricated, right?

Jim

[dtcerrato]

The hot air temp on the cdh is extreme - getting above 200F.
The second cdh install is kicking my butt. The four 42mm ducts are a real pita to route. Got the two short ones in that warm two large bottom bays. The other two are draining persistence as I contort running them to the opposite side and to the rear cabin. Judging from the results of the 1st cdh install it will pay off. The bus will be equipped with four furnaces, two LP & two diesel at 85,000+ total btu. AK here we come!

[s2mikon]

dtcerrato, Did you find a source for the 42mm duct that wasn't 3 foot long each piece? I had to make a number splices to get to having 6-8 foot long ducts. It was a PITA but it was worth it in the end. I am getting ready to mount one at the very front of the coach to take the chill off the door and drivers bay.

[Glennman]

The hot air temp on the cdh is extreme - getting above 200F.
The second cdh install is kicking my butt. The four 42mm ducts are a real pita to route. Got the two short ones in that warm two large bottom bays. The other two are draining persistence as I contort running them to the opposite side and to the rear cabin. Judging from the results of the 1st cdh install it will pay off. The bus will be equipped with four furnaces, two LP & two diesel at 85,000+ total btu. AK here we come!

dt, do those 42 mm ducts move very much air? Also, I take it you are not having any condensation problems, or do you need to install them to drain back to the unit? One more question, do both of your units have the 4x outlets, or just the newer one you speak of?

[chessie4905]

Alixpress has some about 5ft long.

[dtcerrato]

dtcerrato, Did you find a source for the 42mm duct that wasn't 3 foot long each piece? I had to make a number splices to get to having 6-8 foot long ducts. It was a PITA but it was worth it in the end. I am getting ready to mount one at the very front of the coach to take the chill off the door and drivers bay.

eBay item number:304205269756 is 42mm duct @ 2 meters long. I use small tomato paste cans - alter them and use them as terminations or unions, they work great. The 42 mm flex duct I just use for short transitions. Longer runs or runs that are exposed to damage I use a 2"X2" aluminum box tube. The ID of the sq. tube has greater area than two 42mm round flex duct. Improvising & saving more $$$.

[dtcerrato]

dt, do those 42 mm ducts move very much air? Also, I take it you are not having any condensation problems, or do you need to install them to drain back to the unit? One more question, do both of your units have the 4x outlets, or just the newer one you speak of?

I haven't yet fired up the newest CDH that has four 42mm openings. The first CDH I installed some months ago has the one 75mm discharge opening. I have a Y in that line that carries it to two places. I'm certain the 42mm duct move plenty of air. Heck they sell a two 42mm discharge opening so I guess it'll move less air at higher velocity. I haven't had any issue of condensation BUT - it may be credited to me ducting the 75mm clean intake air into the cabin. I was getting "dirty" air over time sitting overnight in truck stops &/or rest areas before I tied the 72mm flex duct to the intake side of the CDH directly into the cabin - cleared the air up.
Some handy notes for air duct distribution: 42mm duct = 1385 area. 60mm duct = 2827 area. 75mm duct = 4418 area. 2X2 box tube (1-7/8 sq. ID) = more than 2 X two 42mm ducts.

[dtcerrato]

Some photos of duct improvising. The flex duct can be easily damaged so in traffic areas such as storage shelves, etc. I run ridged box tube which carries plenty of air for two 42mm flex ducts. the one photo shows a box tube crossing from PS to DS to carry heated air to remote areas. I also choke down the air opening in shorter lines to balance the flow. Once the system is up & running the choked opening size can be changed as needed.

[DoubleEagle]

Dan, it usually is prudent to follow the practice of not using inside air only, but to mix in some outside air as well. If I remember correctly, 20% of the intake should be fresh air (if that is possible at a truck stop). My entertainer Eagles both have fresh air inlets that are incorporated into the system. Even with that, it would also be wise to have a carbon monoxide detector. Seated coaches have fresh air inlets as well.

When it comes to the ducting pipe or hoses, if the temperatures are over 200 degrees at the outlet I wonder if that is too much for the plastic parts. Wouldn't it be practical to use shielded metal until the temperatures decline to avoid hazards, or do the plastic parts withstand the heat alright?

[dtcerrato]

Dan, it usually is prudent to follow the practice of not using inside air only, but to mix in some outside air as well. If I remember correctly, 20% of the intake should be fresh air (if that is possible at a truck stop). My entertainer Eagles both have fresh air inlets that are incorporated into the system. Even with that, it would also be wise to have a carbon monoxide detector. Seated coaches have fresh air inlets as well.

When it comes to the ducting pipe or hoses, if the temperatures are over 200 degrees at the outlet I wonder if that is too much for the plastic parts. Wouldn't it be practical to use shielded metal until the temperatures decline to avoid hazards, or do the plastic hoses withstand the heat alright?

We have multiple avenues of getting fresh air (ventilated) into the cabin besides the CDHs. The plastic parts that are sold with all diesel air heaters are robust in handling temps much higher than 200F. 99% of CDHs sold are all plastic! We did a lot of searching to find the aluminum cased CDHs we purchased. We did install a CO detector & possibly a second one. Your mention of plastic is a good one if in the case a duct register is close to heat sensitive materials - one needs to be diligent and check the whole system & everything it comes into contact with (including hot discharge air). Our LR duct is close to the floor which has a protective plastic runner over the plush carpet so that register points up or sideways otherwise a fire can very easily result. I suggest running a diy installed air heater full blast, hottest setting for an hour or more while investigating the whole system - interior and exterior. The exhausts on our CHDs keep the main fuel tank compartment and the wet bay floor nice and toasty - a fringe perk if done with pure ole' common sense...& diligent testing.

[s2mikon]

Speaking of plastic parts, I purchased some of the grey 42mm like these 304149703596 from ebay and they melted if used within 2-3 foot of the heater. If further out they have been fine. The other 42mm vents that are black have been fine. I used 1.75mm gates green stripe coolant hose cut to 4 inch length to splice the duct hose. I just  lube it with a little ivory soap and twist it in. The other problem has been the 42mm duct hoses falling off the heater. Even clamped it happens. So I have been using high temp silicone RTV.

[dtcerrato]

Speaking of plastic parts, I purchased some of the grey 42mm like these 304149703596 from ebay and they melted if used within 2-3 foot of the heater. If further out they have been fine. The other 42mm vents that are black have been fine. I used 1.75mm gates green stripe coolant hose cut to 4 inch length to splice the duct hose. I just  lube it with a little ivory soap and twist it in. The other problem has been the 42mm duct hoses falling off the heater. Even clamped it happens. So I have been using high temp silicone RTV.

In the details pertaining to grey 42mm like these 304149703596 - it says it's ABS. Got to be real careful as these heaters generate much higher heat than the common RV forced air LP furnaces. ABS won't stand up to heat. If you're saying farther away is ok - BE CAREFUL - it may just take longer to happen. BTDT Also need to be careful of any accessories that are not marketed for CDH. That's why I diy with aluminum + tin. Just saying.

[dtcerrato]

Fired the latest four duct cdh heater up late today. Still have some long runs of duct to finish but needed to see what's what before proceeding. Ran it on full blast for an hour. One has to be real careful because these things can pump some really high heat. The combustion air temp hit 240C that's 464F. The ducts get super hot - no touchy! Some smoke for awhile as all the brand new works are cooking off... Real happy with these jewels