Bosch Condensing Combi Boiler....

[tdesnos]

Hi all,

I'm new to the forum, just thought i'd say hi,

Ok here's my first post:


I've just been to fault find a Bosch CP1 condensing Combi boiler. The customer just had it serviced by a guy, the boiler developed these symptoms shortly after...

- CH fires up on it's own randomly for short periods. Room stats are down to zero, programmer is turned off.
- A demand fr DHW also encourages the CH to fire up.

They can't get hold of the guy, so i've been called into sort it.

So far, i can only think that there is a pull on the central heating causing the boiler to believe there is a demand for it and so it fires up for a bit.

Oh... and it's only the upstairs rads that get hot, i'm assuming this is an air lock, and will deal with that separately - right?

I can only think that the CH and DHW are mixing somehwere? the customer assured me there is not plumbing problem such as the towel rad connected to the DHW etc So i'm thinking the diaphragm on the 3 way valve??????

Please help!!!

Cheers

Tris

 

[tdesnos]

Sorry, make that a Bosch cc1

 

[bengasman]

WB CC1? Any other way of indicating it? Never even heard of that one. Could it be rebadged like birtish/scottish gas installs?

 

[kevindgas]

WB CC1? Any other way of indicating it? Never even heard of that one. Could it be rebadged like birtish/scottish gas installs?

rebadged greenstar or CDi (British Gas)

 

[petit_pablo]

Im not sure which model this is but id disable preheat if you can and see if that stops some of the symptoms.

Sounds like the boiler is intermittantly firing preheat and some of the heat is passing into the upstairs rads. Also when using hw the heat will leak into rads. No idea which diverter is in this one though

 

[tdesnos]

Im not sure which model this is but id disable preheat if you can and see if that stops some of the symptoms.

Sounds like the boiler is intermittantly firing preheat and some of the heat is passing into the upstairs rads. Also when using hw the heat will leak into rads. No idea which diverter is in this one though

Hi mate, so the preheat... this just stores up some water so it's available instantaneously right? How could this be passing into the upstairs rads?

Cheers

Tris

 

[tdesnos]

WB CC1? Any other way of indicating it? Never even heard of that one. Could it be rebadged like birtish/scottish gas installs?

Yeah it's got British Gas all over it mate

 

[tdesnos]

WB CC1? Any other way of indicating it? Never even heard of that one. Could it be rebadged like birtish/scottish gas installs?

Worcester Bosch/British Gas CC1 ZWB 7-29A

that's all i got i'm afraid!

 

[powell30]

GC number would help....then try parts arena

And this would be better in the CC forum

 

[tdesnos]

GC number would help....then try parts arena

And this would be better in the CC forum

Sorry, i think you have misunderstood me friend. I'm not after the part. I'd like help with the diagnosis. Do you think my idea is correct? Do you have one of your own? etc etc

 

[bengasman]

It defo sounds like a sticky diverter, is the system soiled?
Powell is right, this should be in cc. Unfortunately, most of my data is on my other computer, which is on strike at the moment, but the code rings a bell; could be a HE plus.
Does it have a multi function text display?
Any idea of the age? Picture maybe?

 

[petit_pablo]

I know the one, its an early greenstar HE with yellow buttons and a digital display on the front i think. Sticky diverter valve seems the likely culprit

 

[bengasman]

The old HE+ came standard with full text display and access to all underlying software. If the settings got mixed up, it can do all sorts of weird things.
Might be worth resetting it to factory defaults. You can set them up to do exactly what you want, when you want it. You can also easily mess it up big time; I wouldn't recommend playing with it unless you have all the data.
The current CDI's still have the option to stick the diverter electronically in mid position to facilitate draining. Never tried it, but I would guess the same is possible on the HE+.

 

[doitall]

The ZWBR 7-25a is a Bosch Greenstar GCNo 47-311-44 so I would guess the 7-29a is close

 

[tdesnos]

It defo sounds like a sticky diverter, is the system soiled?
Powell is right, this should be in cc. Unfortunately, most of my data is on my other computer, which is on strike at the moment, but the code rings a bell; could be a HE plus.
Does it have a multi function text display?
Any idea of the age? Picture maybe?

multi function text display? Urm... forgive my ignorance here. It has a two digit display on the left just reading the temperature. On the right hand side is just the LCD programmer.

These boiler, were made between 2001/02 apparently. I'm not sure if the system is sludged up i'm afraid.