Ideal Vogue C32 hot water demand

[luciani]

Hi all, just to say I'm not a heating engineer nor gas safe registered and I am not going to attempt any gas work on the boiler.
We've just had a new ideal vogue c32 commissioned. Noticed today that the boiler fires when cold water taps are used. Even the outside tap which is just after main stop valve on incoming cold supply and some way from boiler. The heating engineer suggested it might be crossed pipes - closing off the cold feed to the boiler and then opening all the hot taps we found there was no hot so we assume it isn't crossed pipes. The cold sink tap (much nearer boiler) also makes the boiler fire - but in each case the boiler only heats a small amount of hot water which feeds into the dhw outlet from boiler before shutting down. If I'm allowed to ask for advice does anyone have any thoughts as to what the problem might be? Could it be down to system design? Thank you

 

[luciani]

 

[luciani]

As Scott requested here are some photos. Final picture is of incoming main, stop tap and shortly after the outside tap T's off thru the wall. The boiler is located on the opposite wall about 2.5 metres away, around 3.7m of pipe from this point to boiler. When outside tap is opened boiler fires and then shuts down after a few seconds. When tap is closed boiler fires again for a few seconds before shutting down.

 

[harrygashull]

I think Ideal Insist on having a mini expansion fitted to these anyway if I remember correctly...

If you isolate the cold mains going into the boiler and water still comes out of the hot taps then you have a problem.

If the water coming out of the hot taps is luke warm/tepid then the likelihood is that you have crossed pipes.

If the boiler fires up when cold mains is run and then shuts off then it would be advisable to fit a non return valve to the cold inlet to the boiler and also a mini expansion + pressure reducing valve.

After this then an inspection of the hot and cold pipework would be needed to make sure there are no long dead legs in pipework.

 

[luciani]

Thanks Harry. That's very helpful. When you say a non return valve is that a flap valve?

 

[stevetheplumber]

no you get sprung loaded ones now but in my experience use a 22mm one with reducers less likley to stick

 

[gassafe]

Pretty common fault, there's no crossed pipes just the boilers flow sensor is sensitive & detecting a flow... Normally caused by a dead leg on the hot supply apparently, can be remedied with a check valve / mini shock arrestor it would seem!

 

[Scott_D]

Who fitted the compression bends:stupid:
And what do they supply?
Did the guy who commissioned not fit new pipes?

 

[luciani]

Thank you very much. I appreciate your help.

 

[luciani]

Thanks gas safe. I appreciate your help. That sounds reasonable.

 

[kris]

I've came across this on a few systems, all the remedies have been mentioned below, shock arrester etc, all your pipes will be correctly fitted but that little bit of back flow pressure is activating the flow sensor,

 

[Riley]

If it's a new install why are we not having the installer back?? Unless it's diy the amount of tape on those compressions would imply not pro

 

[luciani]

Thank you Kris. That's reassuring. When the heating engineer said at first it might be crossed pipes it was a bit of a worry especially with all new plumbing. But it's a relief that the solutions have been so helpfully presented here (pressure reducing valve, shock arrester and check valve) can be fitted once the heating engineer comes back. Presumably the 22mm check valve goes before the cold feed enters the boiler while the shock arrester needs to be before the check valve. Hopefully this thread may be helpful if other people have the same issue. I'm assuming it's not specific to this make / model but maybe more to do with system layout?
A big thank you to everyone who's posted - I really appreciate your help.

 

[luciani]

Hi Riley. I'm happy to send you the invoices for the work from the installer to demonstrate we used a gas safe installer if you wish?
The heating engineer is ready to help and is coming back soon to fit the hob. After he'd commissioned it I noticed this issue and, told it might be crossed pipes, I wanted to ask for advice because he lives a long way away. I've been honest about my own non qualification for this sort of work and I think I've been clear that I've no intention of undertaking any work on the boiler.

 

[Riley]

Hi Riley. I'm happy to send you the invoices for the work from the installer to demonstrate we used a gas safe installer if you wish?
The heating engineer is ready to help and is coming back soon to fit the hob. After he'd commissioned it I noticed this issue and, told it might be crossed pipes, I wanted to ask for advice because he lives a long way away. I've been honest about my own non qualification for this sort of work and I think I've been clear that I've no intention of undertaking any work on the boiler.

No no that's fine mate. Wish more people took that approach. My point was really irrespective of how far he lives away he has a commitment with you to remedy the issue. It's good that you're doing some research but if he's any good then from your description he should know what's required