Truma Combi CP plus water heater

We are in Portugal at the moment. On return from the restaurant last night, the mains electricity tripped (6amp on site), so we decided to wait until the morning to ask the site owner to reset it for us as its not possible to do it yourself! First thing this morning I put the Truma Combi CP plus water heater on, using only gas. This is the first time ever that I have used gas only. The heater took a minute or so to fire (clicking) and then went into a continuous noisy rumble. This sounded odd to me, so I switched it off and tried again. Once again it took a while to fire, then started rumbling accompanied by a tinny sound and a background of sound of clicking as though it was trying to fire again. Concerned, I switched it off.

Can anyone shed some light on this please? Does this sound anywhere near normal? The instructions don't give much of a clue, but refer to safety issues, saying the gas exhaust cowling needs to be clear and requires to be regularly checked for tightness especially after long journeys!!

Anyone got any suggestions as I do not want to damage the heater in any way.

Pete

Sorry can't help you Pete, our Truma has worked fine on gas and electric.

John.

Thanks for your reply John. I am sure it's perfectly normal, I just didn't expect it to make that noise. I tried it again with the seat up to see if I could could make out what the noise was. It appears that the rumbling sound is a fan starting at fairly high speed and then after a minute, it reduces and settles down. I guess the fan is necessary to push out the exhaust gases out through the cowl. I am only guessing, it's just I didn't expect it to be that noisy!

Thanks again for your reply. As I said we are in Portugal, right on the borders with Spain. We are near Campo Major and visited Mérida in Spain. It was one of the three capitals of the Roman Empire. Fantastic place, jaw dropping ruins everywhere. Tomorrow we are visiting Elvas nearby, a Roman garrison town with massive fortifications.

Best wishes

Pete

HI Pete we travelled through those towns in 2003 on our Harley Davidson going to the Farro motorcycle rally, never seen so many Storks they were every where.

John.

We have had a bit of rain and wind over the last two days. The storks are nesting at the moment. Some of the nests are enormous and don't look particularly safe. 

I ride a Yamaha XVS Dragstar when the weather is sunny! Looking at replacing it with one of those new retro Yamaha SR 400 (one with the 60th Anniversary yellow tank). Has a kick start though!

If her indoors lets me!

Pete

Hi Pete, like John we don't experience any of the symptoms you describe with your heater on gas mode. Whilst camping last March extensively used the winter setting (EHU + gas) to heat water quicker with almost silent operation. This proves the system should operate without undue noise or vibration to cause alarm therefore bearing this in mind, perhaps getting it rectified.
Regards Colin

Hi Colin, yes like you, we have regularly used the mixed mode to try and speed up the heating of hot water, with no noise or issues. Although when using MIX 1 (elec + gas), we have noticed it hasn't really speeded up the heating of water but not thought much about that, until as a consequence of the fan noise we are getting with using gas on its own, I read the Truma instruction manual. It says under the heading ' Hot water mode' that 'Mixed mode is not possible. With this setting the unit automatically selects electrical mode. The gas burner is not enabled'. According to the instructions for habitation heating, it seems that you can use the mixed option of gas and electricity, only possible in winter!!!  So as you can see I am a bit confused. The option seems to be there for room temperature when it is initially very cold as a backup, switching of the gas automatically when it warms up, but not available for heating water! Someone please explain!

Have people experienced the two level fan noises when just using gas on its own to heat water?

Pete

We had a Truma Combi in our Adria Compact and it was almost silent in operation, on gas and when the fan was working hard. It sounds like you've got a fan that's maybe touching something internally. Having said that I would've thought that would happen when using electricity only as well. I can't remember if the Combi has a fan driven flue for gas operation? If it does then maybe the fault lies there, rather than the general heat circulation fan.

An aside. Mentioning the Adria reminds me it had a small bore leaky hose affair that ran around the perimeter of the transverse double, giving out a gentle low heat overnight all around the bed.