Auxiliary heater '

[Spanner123]

I
Can anyone point me in the right direction. First off I am a qualified mechanic of 40 years now I have a 2006 fiat ducato 2.8 Motorhome it has a heater fitted under drivers seat and can’t turn it off driving me mad can’t find out anything about it can anyone help please i

 

[portland_bill]

Never been close to one, well, not in the last 40 years, and they were rather crude that long ago.

If fitted by the motorhome manufacturer, I'd expect either separate controls somewhere, maybe in the rear compartment if not in the cab, or perhaps tied in with the standard heater controls so they work together.
If DIY fitted, anything could have been done.

If mine, I'd start by following the pipework, to check condition and routing, and see if there was any water valve. Then, is it connected to any control, either cable or electric.
Then, I guess there's a fan in it, so follow the wiring. Rather more difficult, as it may be well hidden. We'd hope the fan had a switch, but may have just been wired to an ignition feed.

Good luck.

 

[Spanner123]

Never been close to one, well, not in the last 40 years, and they were rather crude that long ago.

If fitted by the motorhome manufacturer, I'd expect either separate controls somewhere, maybe in the rear compartment if not in the cab, or perhaps tied in with the standard heater controls so they work together.
If DIY fitted, anything could have been done.

If mine, I'd start by following the pipework, to check condition and routing, and see if there was any water valve. Then, is it connected to any control, either cable or electric.
Then, I guess there's a fan in it, so follow the wiring. Rather more difficult, as it may be well hidden. We'd hope the fan had a switch, but may have just been wired to an ignition feed.

Good luck.

Thanks for reply unit is fitted by fiat no valves anywhere to be seen from what I can find out on web there is a solenoid fitted somewhere I would think on heater box somewhere I am going to do some stripping now to see what I can find will let ye know can’t be only person with this problem

 

[s130]

Only heaters like that in the Ducato that I know of is a diesel fired heat generator. The combustion chamber is probably mostly external under the floor pan and will be fed by diesel fuel line that should have a shut-off valve somewhere.

From the Fiat Professional Ducato Converters Manual:

Heater installation
If a supplementary heater is required, it is advisable to use only the types foreseen by
FIAT CHRYSLER AUTOMOBILES S.p.A.
For vehicles on which FIAT CHRYSLER AUTOMOBILES S.p.A. has not foreseen
supplementary heaters, these must be installed according to the heater Manufacturer’s
instructions (i.e. boiler, piping, electrical system arrangement etc.) and as per the
instructions given below.
All pertinent national regulations must be respected (i.e. testing, special versions for
hazardous goods transport, etc.). The supplementary heater must not use vehicle
systems subject to homologation, if their use may negatively alter performance.
In addition:
- the correct function of vehicle components and systems must be safeguarded
(i.e. engine cooling);
- for the electrical system, check that battery capacity and alternator power are
sufficient for the increased power absorption (see ELECTRICAL SYS. SECTION).
Fit the new circuit with a fuse;
- for fuel supply, connect the supply system to an auxiliary fuel tank connected to the
return pipe from the engine. Direct connection to the engine fuel tank is only permitted
if this is independent to the engine supply lines and the new circuit has a hermetic seal;
- define the routes of pipes and electrical cables, arrangement of brackets and flexible
joints, taking into account their dimensions and the affect of heat from the various
components on the chassis. Avoid passages and arrangements with exposure that could
present a hazard when travelling, adopting covers or guards wherever necessary;
- for water heaters, when the original vehicle heater and engine cooling circuits are
involved, in order to obtain correct system function and ensure the original safety level:
- define the connection points between the supplementary system and the original
with special attention, if necessary in agreement with FIAT CHRYSLER AUTOMOBILES
S.p.A.;
- arrange piping rationally, avoiding kinks and siphon sections;
- apply breather valves to ensure correct system filling;
- ensure the possibility of complete system drain, fitting any additional plugs required;
- adopt, where necessary, adequate protection to limit heat loss.
- In air heaters and in cases in which the heater is installed directly in the cabin, special
attention must be given to the flu (to prevent combustion gases accumulating in the
interior) and the correct distribution of hot air, to avoid direct flows;
- The entire system must be installed to permit good accessibility and ensure rapid
maintenance.