Help please; Truma Combi 6E boiler red light, won't fire up

[Brian Kirby]

Goneoff - 2014-10-25 9:48 PM...........................I’m going to try shorting the thermostat as suggested but will do it after we move off this site on Monday because my gut feeling is the Truma will function correctly. I maybe wrong but will let you know. Thanks again.

I'm sure you don't mean that if it works as it should on the next site, you will assume it was merely a temporary aberration. However, just I case you may, I think you really need to establish the cause while it is still showing the fault. If the fault isn't replicated at the next site, the various tests suggested above won't prove anything. Unless the fault can be replicated on demand (which it seems it can't), you'd then then have to wait until it next chooses to manifest, which may not be for some time, and would merely leave you with an undaignosed intermittent fault. Don't forget it will be getting colder as you return north, so a reliable heater will become more desirable as you travel.

 

Since the heater was previously working OK, the most likely cause looks to be a connection at one or other end of the cable that has shaken loose, or that has been displaced because something has caught on the cable. Testing this possibility should be quite quick and conclusive. Do the 'stat end first, then try strrting the boiler. If it comes back to life job done. If it doesn't, repeat at the other end: ditto. If neither yields results, try the shorting tests as suggested above. I doubt it will be possible to inspect the whole length of the cable to check for rogue staples, or similar so, if the results point to the cable itself, the most practical solution is likely to be to waste no more time on it and replace it with a new one. If the results point to the stat, ditto.

[Goneoff]

Derek Uzzell - 2014-10-26 9:11 AM

 

If the heater still refuses to play ball (and assuming that access to the heater allows it) you could also try disconnecting the sensor-cable at the heater end and cross-linking the two connectors on the heater to which the cable attaches. These connectors are numbered 46 on the drawing on Page 17 of Truma’s Installation Instructions.

 

If the sensor’s cable is the culprit then 'shorting out' the room temperature sensor won’t provide a cure, whereas shorting out the cable’s connectors on the heater should simulate the presence of a connected sensor while removing the cable itself from the equation.

 

I’m guessing that your Rapido has the room temperature sensor over the living-area’s entrance door opposite the kitchen-unit in which the heater is housed. If that’s so then the path of the sensor-to-heater cable will be long and convoluted. If it can established that the cable is the cause of the problem, it should be possible to get the heater working on a makeshift basis until you get home and can get the job done properly.

Hi Derek

 

You are correct about testing the sensor and cable at the boiler end; that really checks out the cable and sensor. But my gut feeling appears at this point to be correct, not that I'm technically adept nor do I have psychic powers but we are now on an aire with no hook-up and the unit is working on fine on gas. It obviously doesn't solve the problem but at least we got a hot shower this morning. I will try and take it into a Truma agent on our way back to get it sorted if not I will short it at the boiler when I get home. Once again many thanks for all your help, you have been a star.

[Goneoff]

Brian Kirby - 2014-10-26 11:24 AM

 

Goneoff - 2014-10-25 9:48 PM...........................I’m going to try shorting the thermostat as suggested but will do it after we move off this site on Monday because my gut feeling is the Truma will function correctly. I maybe wrong but will let you know. Thanks again.

I'm sure you don't mean that if it works as it should on the next site, you will assume it was merely a temporary aberration. However, just I case you may, I think you really need to establish the cause while it is still showing the fault. If the fault isn't replicated at the next site, the various tests suggested above won't prove anything. Unless the fault can be replicated on demand (which it seems it can't), you'd then then have to wait until it next chooses to manifest, which may not be for some time, and would merely leave you with an undaignosed intermittent fault. Don't forget it will be getting colder as you return north, so a reliable heater will become more desirable as you travel.

 

Since the heater was previously working OK, the most likely cause looks to be a connection at one or other end of the cable that has shaken loose, or that has been displaced because something has caught on the cable. Testing this possibility should be quite quick and conclusive. Do the 'stat end first, then try strrting the boiler. If it comes back to life job done. If it doesn't, repeat at the other end: ditto. If neither yields results, try the shorting tests as suggested above. I doubt it will be possible to inspect the whole length of the cable to check for rogue staples, or similar so, if the results point to the cable itself, the most practical solution is likely to be to waste no more time on it and replace it with a new one. If the results point to the stat, ditto.

Hi Brian

 

You are correct it really does need sorting out as there is nothing worse than an intermittent fault the source of which you have no idea. My gut feeling appears at this point to be correct, not that I'm technically adept nor do I have psychic powers but we are now on an aire with no hook-up and the unit is working on fine on gas. It obviously doesn't solve the problem but at least we got a hot shower this morning. Clearly electric hook-up screws it up in someway and I can't replicate it again where we are currently as there is no electric on the aire. I will try and take it into a Truma agent on our way back if i can't get it booked in due to timescales I will short it at the boiler as suggested by Derek when I get home to check out the cable and sensor. Many thanks for all your help and advice.