No Central Heating with young children

chris1012

We have a Potterton Titanium Combi Gas Boiler which was setup with the wireless Nest Thermostat last year to provide heat to our radiators, heat up our unvented indirect cylinder to provide us hot water and to heat up our under floor heating in our kitchen.
There is also one tap in the house that is used to provide hot water directly from the gas boiler instead of the cylinder - Something to do with making sure the 'diverter valve' does not fail and has regular use.

The nest thermostat setup has worked flawlessly for just over a year and tonight when I wanted to heat up my sons loft room, the rads would not get hot.
I firstly checked the nest thermostat and it mentioned it had an issue connecting to the link. I tried to reconnect and it connected straight away (this happens from time to time due to the distance of the thermostat and link).

I then went to check the boiler and it was not heating up although powered on.
I checked the single tap that heats up using the boiler directly and this worked instantly.
Going back to the nest, I then attempted to heat the cylinder up, which again worked - boiler was in operation, same applies for the kitchen.

I then tried to set the thermostat to high temperature (23 degrees) and whilst the nest goes orange and says it is heating up, nothing happens at the boilers end.
At closer inspection and playing with the thermostat from getting the boiler to heat up and off, I can clearly hear click at the links end when it is calling for heat yet no impact on the boiler.

What could be the issue and how can I resolve it please?
I have 3 young children and the loft bedroom currently is at 15degrees and dropping!

Attaching a pic of the boiler in hope it explains the setup better

thorganby

Pull the hinged flap down at the bottom of the boiler.

Any error codes displayed?

What does the system pressure gauge read?

ianto11

From the pic, looks like you have zone valves fitted, these have a little manual override lever which locks in place and will force the boiler to light.

ianto11

Sorry that should've been bottom left.... and are these the valves [URL="https://www.screwfix.com/p/honeywell-40003916-001-2-port-v4043h-replacement-powerhead-22mm-22mm-compression/326FV?tc=TA5&ds_kid=92700040441488950&ds_rl=1241687&ds_rl=1245250&ds_rl=1249404&ds_rl=1245250&ds_rl=1249484&ds_rl=1249799&gclid=EAIaIQobChMIwvrpro2h5gIVw7TtCh34pA_0EAQYASABEgKgxPD_BwE&gclsrc=aw.ds] here [/URL]One will be for hot water one for heating, the little motorised unit maybe gone on the top

p00hsticks

Are you getting hot water from the other taps ?

If so, it sounds possibly similar to the problem we had recently - hot water but no heating, boiler firing up ok but no central heating even though communicating with the thermostat (after being re-linked). [intially we had no lights on on the boiler and OH had to replace the fuse for the boiler, which had blown).

We were also getting a 'pressure over-run' (?) message on the boiler (not the same make as yours).

We couldn't diagnose the problem ourselves and when the engineer came the fault turned out to be the diverter valve which had somehow got filled with water, shorted the electrics and got stuck in the 'hot water' position. The engineer eplaced the valve and all OK now.

Belenus

chris1012 wrote: »

I have 3 young children and the loft bedroom currently is at 15degrees and dropping!

Good luck getting your boiler fixed.

Don't worry about your children. Just make sure they are well wrapped up.

In the 1950s and 1960s, I shared a bedroom with two brothers. There was no central heating in the house, just a few electric fires.

In the winter we would wake up to a freezing cold room with ice on the inside of the single glazed, metal framed windows.

We all survived.

southcoastrgi

ianto11 wrote: »

From the pic, looks like you have zone valves fitted, these have a little manual override lever which locks in place and will force the boiler to light.

The levers won't switch the boiler on they are just for filling the system

southcoastrgi

I'd be looking at the zone valve if the cylinder & underfloor heating works ok

chris1012

Thank you for all your responses.
It turned out to be a faulty zone valve (far right).

I have managed to put in manual override mode and when getting the underfloor heating to come on or/and heating up the cylinder, the rads now heat up as well.

I assume this will not be covered by the warranty of the boiler.

Is the zone valve an easy fix to replace?
How time consuming can it be and roughly how much should parts and labour cost?

ianto11

It'll be the little motor on the head, they are designed to be changed easily, no drain down of system required This link shows the process, albeit little simplified.

ianto11

ianto11 wrote: »

From the pic, looks like you have zone valves fitted, these have a little manual override lever which locks in place and will force the boiler to light.

southcoastrgi wrote: »

The levers won't switch the boiler on they are just for filling the system

Apologies, I should have said that if you have the boiler calling for heat from the stat, locking the manual override lever open will close the circuit through the switch head and allow the boiler to light if the motorised valve head is faulty