Honeywell changed but heating won't come on without hot water being on

[dreamscapeuk]

Hi there,

I'm hoping someone can help. I've just moved into my first own home and am trying to get things sorted out. The issue is with having to have the hot water on for the heating to work. I've had this issue before in my old place and it was usually the Honeywell 3 port valve that gets stuck. In this case I've had a heating guy come and change the Honeywell valve, service the boiler, flush the CH system, bleed etc.. After it was all done the issue was still there. The guy mentioned that the control panel is faulty and I've installed the Hive now but still the same issue.

I'm now looking into this myself as he doesn't to seem to have a clue. If anyone could guide me on what to check I would really appreciate it. The boiler doesn't fire up with just the heating switched on but when I switch on the hot water the boiler fires up and the radiators get warm. The hot water works fine, the issue is just with the CH. As mentioned Honeywell 3 port valve has been changed and the guy checked to ensure the new valve was not getting stuck.

Details

Potterton Suprema boiler
Shower pump installed that powers 2 bathrooms
Picture of HW cylinder and setup attached

Any advice on what to check would be really appreciated.

Many thanks

Kaiser

 

[Echo the husky]

I see a Switchmaster cylinder stat. How many wires are connected to that, a photo would be good, and please post a photo of the Hive wiring too. As well as a photo of inside the wiring centre, if you can get the cover off with that pump pipework over it.

It is likely the hot water off signal isn't getting to the valve. Or the Orange switch wire from the valve isn't connected correctly.

 

[Agile]

I am very sorry that your heating guy was unable to solve your problem.

It is probably a wiring mistake dating back some while.

Unfortunately some guys have rather limited skills. Replace bits at your expense but not extending to diagnosing faults.

Tony

 

[muggles]

As above, almost certainly an historic wiring fault that needs to be corrected

 

[dreamscapeuk]

Thanks for your reply.. where do you think the wiring could be faulty? behind the control panel, by the cylinder or at the circuit. Is it quite easy for someone, who knows how, to fix this kind of issue?

 

[Echo the husky]

Thanks for your reply.. where do you think the wiring could be faulty? behind the control panel, by the cylinder or at the circuit.

It could be any or all, that's why I wanted photos.

Is it quite easy for someone, who knows how, to fix this kind of issue?

It could be a 2 minute fix or rather time consuming to correct. We need more info (ideally photos!) in order to advise further. There is nothing unusual or special about the setup that you have, but if you had a Switchmaster setup of controls previously, the wiring is different and requires alteration to get a Honeywell valve to allow separate control of heating and hot water. Usually the programmer is setup to not let you have heating without hot water, and when the cylinder is hot enough the cylinder stat closes off the hot water port on the valve. To get separate control to allow heating only usually requires an additional wire from the programmer, Hive in your case, to the Honeywell valve.

A quick 'fix' would be to set the Hive to Gravity mode.

 

[dreamscapeuk]

Thanks for your reply.. where do you think the wiring could be faulty? behind the control panel, by the cylinder or at the circuit.

It could be any or all, that's why I wanted photos.

Is it quite easy for someone, who knows how, to fix this kind of issue?

It could be a 2 minute fix or rather time consuming to correct. We need more info (ideally photos!) in order to advise further. There is nothing unusual or special about the setup that you have, but if you had a Switchmaster setup of controls previously, the wiring is different and requires alteration to get a Honeywell valve to allow separate control of heating and hot water. Usually the programmer is setup to not let you have heating without hot water, and when the cylinder is hot enough the cylinder stat closes off the hot water port on the valve. To get separate control to allow heating only usually requires an additional wire from the programmer, Hive in your case, to the Honeywell valve.

A quick 'fix' would be to set the Hive to Gravity mode.

Thanks Freddo, I'll take some pictures when I get home this evening and post them tonight. Many thanks for taking the time

 

[dreamscapeuk]

Sorry for the delay in the pictures.

Pic 1. Wiring for the Hive control unit... slots 1 & 2 are empty (that grey wire does not go to port 2, the pic is a little deceiving)
Pic 2. Wiring for the box to the honeywell 3 valve.
Pics 3 & 4 you can see there is only one wire going from the switch master to the blue box.

 

[jeff the gasman]

edit

 

[Echo the husky]

You will need to get another core from terminal 1 on the programmer base to grey on the valve. The wiring is poorly installed and there are a number of defects present. I would strongly advise calling an electrician to tidy up that wiring. It may be possible to correct this fault without running additional wiring, but it will be much easier for a skilled electrician who is actually there, to check .

Can someone please tell me, why is the mid position valve flex always joined (poorly) on British Gas installations. There is one here, there was one a few weeks ago on another thread, I corrected 2 last year and spotted another today while appliance testing. Are their heating installers being trained to join the flexes? In all the ones I have seen, and the last one on here (can't fully see this one) the flexes were all plenty long enough to sensibly reach the wiring centres.