Hot water but no Central Heating with young children

[chris101]

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
I have attempted to manual turn on the diverter valves as advised on some other threads with no joy (pics attached).

Called the warranty company and the earliest they (HeatTeam) can come out is on Monday....

 

[stem]

The Nest will open up the motorised valves below as required.

...but it is the motorised valves that are actually responsible for starting the boiler [they have a switch inside that operates when the valve is open] When the Nest switches the heating on it will open the heating valve. Is it doing this? Normally, to check; when the heating is set to be 'on' slide the lever on the side of the valve towards manual. If it's loose and floppy the valve is open, if you feel resistance it's closed.

However, looking at yours they seem to have been fixed manually open, so their operation will be overridden. Do you know why? Have you just done this?

Also there are 3. But you only have one Nest Heat link, which can control two motorised valves (one heating zone and hot water) is something else controlling the third?

When they are in auto (and not locked manually open) If the valve isn't opening, then either the valve has failed or the Nest isn't turning it on. Have you tried operating the Heat link manually by pressing the centre button? The green waves should light up and the heating come on after a few seconds when you do.

If the valve is open but the boiler doesn't start then probably the switch inside the motorised valve has failed and is not starting the boiler, or there is a problem with the boiler itself.

 

[ianmcd]

when you manually open the zone valves that you have, they will not bring the boiler on, the manually open setting is for filling the system , it will not bring the end switch on

 

[snb]

heatteam will not solve this under warranty. this is an installation issue and you should call back the installer

 

[oldbutnotdead]

Condensate dripping on the motorised valves won't have done them any good either, that white plastic is a disgrace (not to mention running uphill)

 

[oldbutnotdead]

Using the manual latches on the valves might help you depending on how the system is set up. Do you know which valve does what- a guess would be downstairs heat, upstairs heat and hot water cylinder but it is just a guess. If you can get the boiler to fire up in heat mode (by turning the cylinder thermostat up) you will get circulation through the latched open valves which will tide you over til Monday.There are other options but all require a multimeter and some electrical knowledge

 

[DP]

Using the manual latches on the valves might help you depending on how the system is set up. Do you know which valve does what- a guess would be downstairs heat, upstairs heat and hot water cylinder but it is just a guess. If you can get the boiler to fire up in heat mode (by turning the cylinder thermostat up) you will get circulation through the latched open valves which will tide you over til Monday.There are other options but all require a multimeter and some electrical knowledge

Yes, Heat Team will have a good laugh when they see this setup and are told boiler is faulty. Mind, nothing wrong with the setup, poor quality workmanship is what I see.
That bypass reminds me of drivers with Chelsea tractors parking in supermarket carparks as close to the store entrance as possible.

 

[chris101]

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

The two on the left (underfloor and cylinder) I put back to auto and far right zone valve I put on manual override.

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/easy to replace?
How time consuming can it be and roughly how much should parts and labour cost?

 

[fezster]

You should be able to change just the power head (older valves required a full drain down to remove the head):

https://www.amazon.co.uk/gp/aw/d/B003EJCDDQ

It's a fairly straightforward swap over but will require the new one to be wired in. Depending on your competency, you may want to attempt it yourself.

 

[oldbutnotdead]

Usually the actual valve itself is fine, just the motor and switchgear need replacing. Easy DIY job, £40 and about half an hour. WARNING mains electricity involved, isolate and test for dead before removing the valve cover. If these are unfamiliar terms then seek more advice (buy a multimeter when you go shopping for the valve head).
That condensate pipe needs redoing as a matter of urgency, you don't want a repeat never mind damaging anything else below the boiler.

 

[dilalio]

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

Its an everyday job for us. 2 of my jobs yesterday were actuator swaps.

You just need a replacement power head... Most times (and likely in your case) the valve body is fine and no plumbing work required. New head replaces old with 3 screws (1 to remove the case and 2 holding head to body).
Trickiest bit is the rewire into the wiring centre but you can get 5 terminal Regin plugs that will enable you to cut and splice just the old mcv cable to the new.

Do note however that yours looks to have had a leak from above dripping into it which is a suspect in its failure, replacement could go same route if water ingress persists.

 

[dilalio]

https://www.screwfix.com/p/honeywel...acement-powerhead-22mm-22mm-compression/326fv

https://www.wolseley.co.uk/product/regin-rege105-5-way-connector-p459248-44/

 

[dilalio]

To add...

If the installation is less than a year old and your installers are reputable, I would suggest you contact them on the basis that a zone valve has failed prematurely due to water ingress from a leak from their installation... Both issues you would expect them to resolve... Again, depends on their reputation!

 

[chris101]

Thanks for all of your help.
I managed to purchase a HONEYWELL 40003916-001 2-PORT V4043H REPLACEMENT POWERHEAD 22MM 22MM COMPRESSION from screwfix and watched a youtube video of how to change the motor from the old zone valve.
Was very straight forward and although it was difficult getting a thin enough screwdriver to get the case/motor off.
All working again now.

Thank you all!

 

[oldbutnotdead]

Take it the installation is quite old then (or you don't want them back in the house). That condensate pipe needs sorting.....