I have an A Class Carthago motorhome on a 2017 2.3 150bhp X290 front end. The heater performance is very poor requiring the fan to be up to max to get much out of the heater outlets.

I can’t see any ram type air intake for the heater so would like to understand where the original Ducato cab van gets its air and where that intake is on the heater unit?

I’m hoping I can fit some tubing to get the air to the heater, or is the heater just poor in standard configuration.

Richard

As a start I'd check the pollen filter isn't excessively clogged as that can cut a lot of air flow

I have a Burstner A class, and it is similar with regards to airflow, once an aircon engineer came to re gas it, and commented that even on full fan, the amount of air blowing was ridiculously small compared to a standard van. Mine is an X244.
I find that there is only one inlet to the air plenum chamber on mine, thru a 3 inch hole covered with nylon mesh to keep solids out; this in effect strangles the heater and air con potential. I don't know what yours has, but I imagine it will be the same issue, and will likely be unalterable, or else need a great deal of ingenuity and modding to improve this. Mine does not have a pollen filter, and if I can find a pic I will post on here. The intake is on the inside of the front nearside wing, near the top corner of the bonnet.

I’m not aware of any intake on the Carthago so was interested as to where the original intake was to see if I can get any additional ducting to it.

Thinking back to our Rapido, the small inlet that they fitted was to the right of the engine bay.

Richard

The standard X290 air inlet is from bonnet scoops which feed into the interior via a large inlet located on the passenger side roughly above the ECU. On most A class motorhomes I have seen the convertor fits an adaptor to it with hoses to pick up fresh air.

The only pic I can find- see the black tube, top right. It comes from the little inlet I mentioned. It goes to a bespoke plenum chamber above the engine made of glassfibre, and I could in theory adapt it to take nother tube, but there is nowhere to put another inlet, and if I just cut a hole in it it would take hot smelly air from around the engine. Space and heat are the difficulties with adding another air inlet.

Thanks for the info guys, once the weather improves I’ll take a look under the bonnet of my Carthago to see if there is anyway I can increase the air flow.

RichD1 said:

Thanks for the info guys, once the weather improves I’ll take a look under the bonnet of my Carthago to see if there is anyway I can increase the air flow.

Click to expand...

Rich
This is the air intake for the heater on standard X250/290 rhd

Wow!! That’s quite an intake. And does the air come down from the grilles on the top edge of the bonnet?

RichD1 said:

Wow!! That’s quite an intake. And does the air come down from the grilles on the top edge of the bonnet?

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Yes. On the X250 the grills were part of the bonnet On the A class motor homes I have looked at the vehicle converter has constructed a fitting which connects to the intake which is shown on the photo, with one or more air intake hoses attached which go to the front of the vehicle to collect the fresh air.
The photo shows the X250 scoop, the X290 is similar.
Can you take a photo of your under bonnet arrangement?

Having said all that if I set my fan position to 4 with the air intake set to recirculating e.g as I do when using ac, then I still get a healthy flow of air which of course has nothing to do with the 'bonnet scoop system

rayc Hi Ray, have you still got your Rapido? Had to downsize from the 9009DFH because of licence restrictions to a 3500kg van and the Carthago was the only van with an island bed at that weight.

I’ve now managed to get my head under the bonnet and have discovered a large plenum at the top centre behind the engine with two 100mm flex’s tubes coming out and then going out to behind the headlights each side but the ends point straight down and have no direct access to air ram when moving.

I think these could be re-routed to finish pointing out of each side of the Carthago front grille. Water getting in would not be a problem as the plenum is quite a bit higher than the front grilles.

Richard

I have replaced the Rapido and now have a Pilote P740C coachbuilt. Great island bed layout on 3500kg. Of course if it is to be used to full potential then a weight upgrade to 3850 is recommended.
I don't know how important air ram is as I can get a good flow of air on high setting even at a standstill. I would be concerned though as to the fumes that could get drawn in especially in traffic. Just to confirm you have the control set to fresh air and not recirculating??

Limited to 3500kgs I’m afraid.

Yes, heater on external rather than recirculating. I have to admit having read the handbook several times I’m still not sure how the Fiat auto heater system works. Even when from a cold start and on ‘auto’ and temp turned up to 23c the heater never blows out hot or turns the fan speed up as my BM does from cold. I have to go into manual mode to get any real hot air.

With the pipes attached to the front grille and well ahead of the engine I don’t think there is too much risk of engine fumes.

BTW, this all started because my feet were always cold and I discovered that there was no heat ducting to the drivers footwell! This apparently is only applicable to RHD comfortmatic Fiat chassis. Because they fitted a footrest due to the lack of a clutch and this blocked the air flow. To fit this they removed the bottom section of the drivers side ducting. I’ve now fitted some ducting to this outlet and routed it down around the steering column to exit pointing down on my feet. Whilst fitting this pipe I noticed some wire terminals on the piece of ducting left behind the heater unit. You can see them in the attached photo. I’m starting to wonder if this was connecting to a heater temperature sensor fitted in the output ducting that has been removed. Wish I could get hold on a workshop manual.

Richard