How to remove DHW heat exchanger that's too close to case?

[PHILOSOPHERDAN]

Hi

My first post here, though have learnt a lot through reading other posts.

I have a Vaillant Ecomax VUW236 - not sure how old but maybe 12-15years? Has been extremely reliable.

The problem is that the hot water from the taps - and especially in the shower - is not as hot as it should be (and as it was) even when the control panel knob is turned to maximum. From reading the forums I suspect the DHW/Secondary heat exchanger needs cleaning (or exchanging - there is a new one on ebay for £58 inc postage). Is this likely?

I thought I would try cleaning the DHW heat exchanger and see if it made a difference, but unfortunately it has been installed so close to the boiler case that there is not space for it to be slipped off the pipes in the usual way. (Please see photo below) What should I do?

If I trace the pipes from the DHW heat exchanger then they do arrive at nuts where they connect to other pipes, and I wonder whether by undoing those nuts I would be able to remove the DHW along with the pipes? Or whether that would enable me to at least shift the pipes enough to give me enough space to then slide off the DHW heat exchanger?

Would this work? And most importantly: would undoing those nuts and moving the pipes land me with unexpected problems (leaks or something else which I am not knowledgeable enough to foresee)?

Extra info: Heating is working well. It was quite sludged up before Christmas but I replaced all 4 radiators (its a 1 bed flat) and flushed with mains water, then ran heating with Sentinel X800 for 4 days before flushing again. Now I have refilled with X100 inhibitor and X200 anti-kettling fluid.

Thanks very much for your help

Best wishes

Dan

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• PHILOSOPHERDAN
• 6 Feb 2012
• 1

Untitled

• PHILOSOPHERDAN
• 6 Feb 2012
• 1

Untitled

• PHILOSOPHERDAN
• 6 Feb 2012
• 1

Untitled

• PHILOSOPHERDAN
• 6 Feb 2012
• 1

 

[Dan Robinson]

Take the side panel off

Not that you need to. The HEX will just come out when the pipes are disconnected.

 

[The831Bunny]

+1

 

[patsmotors]

how big are your hands ?

 

[PHILOSOPHERDAN]

Thanks for your replies.

My understanding (both from having loosened the nuts to see what happened, and from what the Vaillant manual says) is that the Heat Exchanger needs to be slid to the left , (ie towards the side of the case, looking at the photo), to remove it from the 4 pipes. So simply loosening the nuts is not sufficient.

As for removing the side of the case - is that definitely possible? I mean what is blocking the DHW heat exchanger is the grey strut that can be seen in the photo, and I thought this was part of the frame of the case. Can the left side of the frame be removed without affecting the boiler itself? I thought perhaps the frame of the case supported the boiler, is that not right?

My hands are fairly large but not unusually large - why?

Any help much appreciated

Best wishes

Dan

 

[Dan Robinson]

There is no mention in the manual about having to remove any casing, although it does tell you how to elsewhere.

You also have do disconnect the two push fit connectionsvat the back. I assume there is a circlip of some sort.

 

[Bunnyman]

Ur right simply loosening the nuts is not sufficient! Try undoin em completely then the heatexch will come out

 

[PHILOSOPHERDAN]

Thanks for the replies.

I have tried fully undoing the nuts, and the clips, but that does not allow the Heat Exchanger to be moved perpendicular to the pipes. It needs to first be moved away from the pipes, to the left (as mentioned by Dan Robinson, there is a push fit). Because of faulty initial installation the heat exchanger is too close to the strut of the case to be able to move it to the left. Thus I need an alternative.

Dan Robinson suggested above removing side of the case, but I am not clear whether it is possible to remove the frame on the left (which is what would be required to mak space to remove the DHW heat exchanger) or whether it is needed to support the boiler? So is this something I can do or not?

Another option that occurred to me, is whether it might be possible to trace the four pipes from the DHW Heat exchanger and undo the nuts at the next joints, so then take out the DHW along with the pipes (or then move the freed pipes to the right, thereby giving room to move the DHW heat exchanger to the left). But would undoing those nuts and releasing and moving those pipes work, and would it risk other problems?

Best wishes

Dan

 

[Bunnyman]

hi mate its not a faulty install of the heat exch thats how they all come, its one of the wonders of being an engineer! follow the pipes as you say and undo there to give some play, mind you this was one of the poorest models vaillant made your lucky it lasted so long most only did 5years.