Replacing Truma Rapid BEG boiler

May 12, 2018
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I am replacing a broken Truma rapid 10 litre gas and electric boiler with a new one. The same connection are connected but there is an extra grey cable which is for connection to the controller. However my previous boiler did not have this cable and worked on the existing connection with the existing controller. Do I need to connect this extra grey cable to one of the existing cables or can it be taped off and left UNCONNECTED?
 

Damian

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Mar 14, 2005
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Your new boiler has two elements, 850w and 1300w, the cable is intended to be connected to the appropriate controller to select either of the elements.

If you are not confident, get a qualified engineer to do the electric work, it will save you a headache and possible damage.
 

JTQ

May 7, 2005
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If you are competent to do the job and only lack knowledge of what the wiring connections are, does this help?
https://www.truma.com/web/downloadcenter/files/truma-watersystems-ultrastore-rapid-installation-operating-gb.pdf

This is the root source if that link does not work:
https://www.truma.com/uk/en/service/truma-manuals-instructions.html
 
May 12, 2018
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Thanks for your response. Yes I am competent to do the job. I have the installation instructions but they don't help. The issue is that although the old and new are the same model connecti g it to the existing wiring and controller leaves this grey cable over despite all old connections being in place and connected. On the old boiler a wire comes out of the heater element, loops back into it. On the new boiler the grey cable comes out of the heater element, does not loop back in, but comes out to the three black (1,2,3) and the green/yellow earth cable. In the instructions this grey cable should connect to the new controller. But since the existing controller is connected in exactly the same way as with the old boiler, I am puzzled as to what to do with the new grey cable. I wonder if I just insulate it and leave it UNCONNECTED would that be ok since the old controller is connected as initially. I am also wondering that if I do that, will the old controller be ineffective? Sorry for the long reply, but it is a real teaser.
 
Apr 19, 2017
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Drew,
You say you are replacing with the same model boiler. How did you select 850W or 1300W with your old installation? If in fact your old boiler only had an 850W element then usually this would have been controlled by a simple mains on/off switch. The 'control panel' was related solely to gas operation.

Your new boiler has a dual 850W + 450W element. The two elements are used in parallel if you want 1300W.
Truma never provide proper circuit diagrams (only wiring diagrams) on the assumption you will always use their proprietary accessories.

You say you are competent, so it will be easy to work out the relevant connections to the heater element. If I were replacing my old 850W model, I would simply hard-wire it for either 850W or 1300W via my existing switch.
 
May 12, 2018
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Thanks for your response. My old boiler has a controller were i can select three loadings; 500 watt, 1000 watt, and 2000 watt. Do you have a wiring diagram that i coukd use?
 

Damian

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Drew1950 said:
Thanks for your response. My old boiler has a controller were i can select three loadings; 500 watt, 1000 watt, and 2000 watt. Do you have a wiring diagram that i coukd use?

Are you sure????????

The Truma Ultrastore water heater was only produced with either 450w or 850w elements and only one.
Therefore they were either On or OFF.

The control with selection of power to 500, 1000 or 2000w was for the Ultraheat space heater, which has nothing to do with water heating and is located behind the gas fire.

In all the years I have been servicing Truma equipment I have never found a Ultrastore with your setup !!
 
May 12, 2018
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Sorry, you are correct, I mixed up the space heater controller. Can you tell me how I connect the grey wire please? Can I connect the grey cable some how to make it work. What I don't understand is all other connections to the new boiler have gone exactly as the old boiler. Do I need to install the new controller as well as having the original still connected as before? I really appreciate your help. Thanks
 

Damian

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Mar 14, 2005
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I have not had any dealings with the BGE series of boilers as of yet so will not venture any advice on connections.
I strongly advise that you get a local mobile engineer to sort it out.

My initial thoughts are that as well as the control for the gas working of the heater there must be a selector control for the use of the elements and possibly an isolator switch.

What parts did your new boiler come with????
 
May 12, 2018
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The new boiler came with all needed for an original instal including two controllers. One of the has the matching connections to the grey cable.
 

Damian

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Drew1950 said:
The new boiler came with all needed for an original instal including two controllers. One of the has the matching connections to the grey cable.

Then you have answered your own question.
STOP trying to use the old controls and use what came with the new boiler, if the cable you have been asking about has connection to one of the new controllers, why on earth are you messing about??????????
 

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