Combi Boiler No Hot Water

6 Sep 2003
Reaction score
United Kingdom
I have a Trianco oil fired combi boiler (about 5years old). It recently stopped giving out hot water unless I also turned the heating on.

Does anyone have any ideas please. Do I need to call a plumber ?
Sponsored Links
Thanks for the reply suggesting that a divertor valve may be faulty, hence no hot water unless the heating is turned on.

Does anyone know how to fix this problem ? Is it something I can attempt myself (if so does anyone have instructions ?) or do I need to call in a plumber ?

Is it possible to tap the relevant part to release it ??

Please help.

Sponsored Links
To be honest I'm not a lover of Combi boiler at the moment :!: so I don't have much to do with them but we do have expert plumber's with combi experience on this forum so hopefully they will answer your question shortly.In the meantime the divertor valve look like this. They're pretty straight forward to do and I think the 3-port divertor are not cheap.You could also try moving the manual handle on top of the valve to see if you can loosen it.
Hi Dave,
I would not start tapping the valve! it won't help.
I had a similar problem and with power off I removed four screws and with valve in latched position (use small lever provided on side of motor)remove motor assembly.
Tried to turn spindle by hand, which I did but I could feel some resistance, after a few turns it did feel easier and then decided to add a little WD 40 and work that in.
Replace motor and no problem since.
:rolleyes: :rolleyes: :rolleyes:
Masona.. that picture looks like a motorised valve to me :?:
The divertor valves that I have come accross where nothing like that one.
Where is the diaphragm supposed to be...???:cool:
:oops: :) Glad somebody awake :!:

Like I say I don't know much about combi,how about this then..

I think the diaphragm was in front of my eyes at the time :!: :LOL:
Ahh.. thats more like it ;)
Now thats what I call a divertor valve :) :) :) :) :)
Thanks for the information so far.

I have checked in my Trianco book and have noticed a possible solution to the no hot water problem.

It suggests turning power off, and removing micro-switch assembly by pulling off circlip.

Unfortunately, I do not know where this is. any ideas ??
Its probably on the bottom of the divertor valve assembly..
Its more than likely on the end of the divertor valve. What does it say to do with it after you have taken it off :?: :?:
Masona's diverter valve reference was correct (yes, it's also known as a motorised valve) but as it happens the HS3 is the type used in the Trianco Combi 65 at least.
DaveHello, I suspect you will find the microswitch assy on the flow switch,if at all, but my info has no mention of such assy.
Which model is yours?
Does the burner start immediately a hot tap is turned on? If not, look at flow switch circuit.
Does burner start only when heating is selected? Possibly confirms flow switch problem.
You may also have a hot water thermostat fault.
let me know what you find. Best of luck

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links