# Truma c3400 no hot water flow?



## phil5062 (Jul 8, 2009)

Hi, hopefully someone can help me please!
i can't get hot water to flow from taps.. I can hear the pump going..
There is blown warm air... the water temp light goes out (indicating water is up to temp) but no flow...
I have tried opening the drain valve.. The contents flow out with a trickle ( the puddle on the drivewayhas a few bits in it looking like limescale)

Have i killed it? i can be certain it hasn't been on when my water tank has run out!!

Out of interest, if i've killed it. what am i looking at paying for a replacement?

Many thanks
Phil


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## rayc (Jun 3, 2008)

I guess the first thing is to check if cold water is actually getting to the boiler by disconnecting the inlet and seeing what happens. If there appears a decent flow from the pump then reconnect it and disconnect the output and see what you have there. 
If no output then a descale it using white vinegar [I believe]. Ray


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## camper69 (Aug 30, 2007)

I assume there is water in the tank?

Assumimg that there is water in the tank check that the pump is pumping water by disconnecting the outlet on the pump and running to check water comes out. If not the filer could be blocked

I assume that you have closed the dump value?

You don't want to think about the cost of a replacement

Derek


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## phil5062 (Jul 8, 2009)

Many thanks. I'll go out and see if i can find the water inlet..
Although i feel that the lack of flow when i open the drain valve and the presence of 'matter' that has previusly flowed out makes me think that i've knackered the lining. (vitreous enamelled, never to be switched on when empty)

oops


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## clive1821 (Mar 27, 2010)

one of the simple things i was told to do was, to open up all the HOT water taps and see if theres flow of water... this may be just an air lock... when you have a good flow out of all taps then put the hot water on to heat again.... if thats has already been tryed... i agree with other comments, check the flow into the boiler, and if thats ok theres a lime scale build up.. which could mean a replacement tank for your heater... etc..


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## phil5062 (Jul 8, 2009)

cheers for all that.. I've got good flow into the heater ( I disconnected the pipe at the frost drain valve turned on the tap) 
then i disconnected the red pipe on the side of the heater (high up ) and with the hot tap 'on' there was no flow out...


scratching my head where to go now

cheers


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## Jezport (Jun 19, 2008)

I presumed the cylinder is stainless steel, if the deposits you have noticed are flakes of lime scale then I bet there is a blockage of lime scale.

You have 2 clues.

1 Poor flow from dump valve
2 Lime scale in water

You need to de-scale it


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## rayc (Jun 3, 2008)

phil5062 said:


> cheers for all that.. I've got good flow into the heater ( I disconnected the pipe at the frost drain valve turned on the tap)
> then i disconnected the red pipe on the side of the heater (high up ) and with the hot tap 'on' there was no flow out...
> 
> scratching my head where to go now
> ...


Is the frost drain down valve the same as the cold water inlet to the boiler? If there is a blockage at the boiler it is most likely in the inlet or output and not within the boiler cylinder itself. When you disconnected at the top did you remove the red hose or the complete fixture which is the pressure relief valve/ outlet?


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## clive1821 (Mar 27, 2010)

so there's a good chance that is blocked up with lime scale.... if so its a matter of removing the boiler and striping it down to clean it out and replace some of the parts, perhaps the internal filters... you can get replacement parts so its not the end of the world... hope that helps


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## Jezport (Jun 19, 2008)

You should be able to de-scale it without a stripdown, you just need to get the de-scaling solution into the boiler.


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## phil5062 (Jul 8, 2009)

Many thanks for the amazing level of response and help.

Well, my boiler isn't the stainless one. 
and when i checked for outlet flow ( red hose) i only disconnected the red hose from the 't' piece.

( the drain down valve is (hymer b544) low down on the left hand side of the boiler, i disconnected the hose going into the valve) when i have the drain valve open and a tap running, water has pissed out. 

I'm flumuxxed


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## rayc (Jun 3, 2008)

phil5062 said:


> Many thanks for the amazing level of response and help.
> 
> Well, my boiler isn't the stainless one.
> and when i checked for outlet flow ( red hose) i only disconnected the red hose from the 't' piece.
> ...


You havn't yet proved that water is getting to the boiler input. Disconnect the hose at the boiler and make sure you have water there. {If the boiler were full of water and you opened the drain valve then the boiler would empty - yet you say there was only a dribble!}.
If you are sure that water is getting to the boiler inlet then disconnect the T piece { presure releif valve }at the boiler output and check you get water there when the pump is running. 
If the answer is No then connect a mains pressure hose to the T piece hot water out port and feed the cylinder backwards and see if you get water coming from the inlet. {switch the mains tap on slowly and not to full pressure}. If you do not get a flow through the boiler then it is blocked.


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