Heater not working - help

Hi blower works off 12v have you got 240v to heater on. I have a switch in the wardrobe close to heater. And the thermostat up high. Try without blower on as heater will warm up farster

With the heater power switched on you should also have a rotary type thermostat switch that can be set to 500/1000 or 2000 and there should be a green light on it if the power is working. 

The heater's electric element may have failed or may not even be fitted. Have you previously had heat from the electrical settings? 

Not sure about your model/make of heater/blower system, but the Fanmaster heater/blower systems have an electric element overheat cut-out reset button inside the heater it's self. This is should for whatever reason the fan motor fail, it stops said electric elements from burning out. This reset button is not mentioned within the Fanmaster instructions for HSE reasons, it just says, words to the effect of "contact your dealer". To access this reset button within a Fanmaster, one has to dismantle the heater (which maybe why it says contact your dealer). To this end, it is possible your make/model of heater/blower COULD be a simular design. If all else fails, it maybe worth a competent DIY person having a look for such possible reset button!

Colin

As a previous poster suggested could be the heating element has blown. 

Possible burnt-out Heating Element?

May not be as likely as one might think; Depending on the make/model of said heater/blower, the chance of it having a single element is highly unlikely. They normally have a two or three phase electric element, therefore the chance of them burnng out at the same time is very unlikely. As I said within my last post, there is most certainly a overheat cut-out reset button inside the heater/blower. In theory, this would cut-out if the fan motor failed or if all the outlet vents were closed, the they are not auto-reset. Best as I said, ask a competent DIY person to check inside for said possible reset button.

this heater is a truma heater  it has no reset switch on it aparently

 

Sorry, I find that very hard to believe, as said within my first post, the fanmaster heater/blower instruction leaflets don't tell you about the said INTERNAL reset button, the only way I've found out is that I dismantled & repaired two of them a few years
back. I understand that these heater/blowers (whatever make/model) all work on a very simular principle, they all must have some kind of cut-out/reset to protect the electrical elements on fan failure or air flow blockage. To this end, without having "hands
on myself" I cannot help you anymore in this instance.

Colin

I did know it was not fitted with a Fanmaster, only quoting a Fanmaster as an example, as I've repaired two of them a few years back and they all work on a very simular principle.

metz, fair comment! It appears you know more than I on this subject.

Colin

Agree with metz that if the green light in the switch does not light, then you have no 12v on the PCB  (this 12v comes from the transformer on the PCB .... it is nothng to do with the 'van 12v supply).  However you still need to adopt a methodical fault-finding approach before concluding that the transformer and/or the PCB is at fault.  240v mains may not be reaching the transformer.   (usual warnings here: DO NOT attempt to faultfind with mains connected!).  However it is quite possible (with mains supply completely disconnected) to use an ohmmeter to check the circuit through to the transformer (and indeed the transformer).

If the transformer has failed (fairly common), it is a standard component and readily available (eg CPC-Farnell) for a couple of pounds. Not difficult to replace if you are competent at soldering .... or find a local electronics ethusiast!   Otherwise exchange PCBs are available (ebay) for around £50.  New ones are nearer £100.

For info, the other very common fault is for the green light to work, but the heater only works on the 500w setting. This is caused by failure of one or more of the 3 relays. There is a fiendish bit of circuitry which puts the two heater elements into either series (500w) or parallel (2000w). This is often blamed on vibration, but I do not go along with that (unless you drive along with the heater connected to mains! ...HA-HA). I have opened up failed relays and it's always welded contacts. There seems to be inadequate damping in the thermostat circuit sometimes leading to relay 'chattering' and consequent arcing.  Again, the relays are readily available at about £1.50 each

In theory, if a 50uf (or near value) capacitor was fitted across each relay coil this could cure the said relay contact problem.

Vicmallows;

Many thanks for answering my question, I fully understand what you have said within your above post, very well explained to say the least! I must admit, I have learned some quite valuable information from yourself and Metz about said Truma Ultraheat heater/blowers. I understand how the old Fanmasters work as I have successfully repaired them in the past. My knowledge of other makes/models is limited due to lack of experience, hence ackknowledging to Metz that his/her knowledge on these heaters is greater than mine. My speciality is vehicle electrics as this was my previous employment. Reference to my previous post regarding said capacitor accross the relay coil, Without going into in-depth detail, I have found on many occasions (not all) that when experiencing relay chattering of similar manner, placing a capacitor accross the coil acts as a damper for the relay contacts if you know what I mean, above I quoted a 50uf, thinking again, it might be better with a 100uf, as you are aware, each scenario is different i.e. possibly needing a different value. Once again, many thanks, I look forward to reading your future posts.

Kind regards

Colin.

PS, I understand what you mean about typing on a tablet!