Heating issue

[Tony 1]

Hi, I’ve recently moved into a new build which has 14 rads in total (7 upstairs & 7 downstairs) running off a Tribune XE unvented cylinder. We had a Hive thermostat fitted by British Gas a few months back and for the past couple of days I’ve noticed the 2 rads in the living room are stone cold when the heating is on yet all the others are scorching hot. I’ve bled them and gone round them to balance them up etc & still no heat. If I manually open one of the 3 motorised valves at the cylinder I begin to get heat to the living room rads but if I turn the stat off you hear the motorised valves closing I’m assuming but when the stat is turn back on for heat, again I get nothing to the living room rads unless I manually open the motorised valve. Any ideas why the valve is not opening automatically? Many thanks

 

[oldbutnotdead]

Has this problem just developed or has it existed since the Hive was installed? What type of motorised valves do you have? (Pics are the easiest way). Do you know which valve controls which zone? Is there a separate controller somewhere? (Hive usually has 1 or 2 circuits, sounds as if you have 3 zones to control). Do you own a multimeter and know how to use it?

 

[Tony 1]

If I’m honest I’m not 100% sure as I only noticed the other night but it definitely worked before the hive was fitted. We have 2 stats, one being in the living room however the gas engineer bypassed it so the hive would turn on all the rads together. The red taped valve is the one that controls the living room and they are Honeywell motorised valves. Yes I have a multimeter and I can use it.

 

[sircerebus666]

Generally when something stops working after an engineer has changed the system, it's whatever they have done which has caused the issue.

It's strange that the living room stat is bypassed and now the living room rads won't warm up, that tells me that he didn't rewire it correctly , I've also noticed a link wire is loose at the bottom of your pic too.

If you post a pic of all the control wiring someone will be able to tell you if it's wired correctly

 

[oldbutnotdead]

Presumably, when you used the manual override lever on the motorised valve you put it on the latch? My first thought was that BG have linked the wrong pair on the downstairs thermostat so the downstairs valve is opening when the Hive reckons it is satisfied- if the valve is closing after it has been on the latch then it is being driven open at some stage. You might want a friend to play with the Hive while you lurk at the valves to see what is doing what when each zone (hot water and heating) are played with.

Looks like quite a nice install...

 

[Tony 1]

The lever on the valve doesn’t stay on the latch, I can only slide it across to manual to open the valve but can’t actually lock it onto the latch. Would the position of the Hive make any difference to why the living room won’t come on as it’s mounted in the hallway at the minute?

 

[ericmark]

My first thought is why are there motorised valves with Hive, the Hive TRV heads remove the need for motorised valves, so it is clearly some cut down version where some one has tried to save money by not fitting Hive TRV heads.

If I manually open one of the 3 motorised valves at the cylinder I begin to get heat to the living room rads but if I turn the stat off you hear the motorised valves closing I’m assuming but when the stat is turn back on for heat, again I get nothing to the living room rads unless I manually open the motorised valve.

That seems odd, if the valve will hold it open, then it should open the valve one would have thought, however I seem to remember reading some where there is a diode or a resistor designed to remove the load once valve fully open, so maybe there is an internal micro switch in the valve which has stuck?

I would remove valve head and check spindle to see if spindle is free or not, maybe remove a second head so you can compare the two. If spindle turns OK then swap the head for a new one, if spindle tight then swap the valve.

 

[oldbutnotdead]

The lever on the valve doesn’t stay on the latch, I can only slide it across to manual to open the valve but can’t actually lock it onto the latch. Would the position of the Hive make any difference to why the living room won’t come on as it’s mounted in the hallway at the minute?

Odd. The manual lever does flex a bit to let you bend it onto the latch- almost sounds as if the valve is already open when you're trying to manually override it. Re the position of the Hive transmitter- if any functions work on it then all functions should work. That's assuming it is a wireless controller (I've stayed away from these IoT devices until some sort of standard emerges from the current mess). As before, find a friend and get him/her to mess with the controller while you monitor the valves (or if wireless, move it to the airing cupboard and do it all yourself)

 

[ianmcd]

My first thought is why are there motorised valves with Hive,

very few Hive installations use the Hive TRV heads

 

[stem]

The wiring looks OK from what bit of it I can see. What the Hive installer has done is connected the two heating motorised valve live wires together with this red loop. So that they both open together.

Following the wire from the valve with the red tape on it appears to go to the bottom of the two terminals highlighted above, so that would be one connection to check. The blue neutral from the motorised valve that connects to the horizontal terminals to the right would be another.

If they are OK, you can then use your multimeter on the two aforesaid (L) and (N) wires and look for 230V when the heating is running, if it's there, then the wiring is OK, the valve is receiving power, but it just isn't opening. So a new valve actuator is required.

When I say the wiring looks OK, electrically it does. However, as your home is a 'new build' it is now in contravention of the building regulations. Since 2010 Part L of the building regulations stipulates that the heating has separately controlled zones for the living areas and sleeping areas.

So if I were you, I would be inviting the installer back to rectify matters, and reinstate the two zones. An additional single channel Hive will be required. A bit surprised to hear that BG have been complicit in this contravention though. Perhaps if you point that out to them and indicate that you plan to contact your local building control, you may get the second Hive gratis.

 

[ericmark]

There is the Part L building regulations and there is the approved document for Part L which are not the same.

The whole reason for the introduction of the Hive TRV was so Hive would comply with Part L building regulations, so with a new build post 2010 either you need zone valves and two Hive thermostats or Hive TRV heads and one wall thermostat.

Until this year it had to be two wall thermostats as there was no Hive TRV heads, so it is quite new, as to using other makes of programmable TRV head think it would comply, but when the head demands heat it would not turn on the boiler.

But BG should know the rules, so either multi wall thermostats or TRV heads, it needs to have one. That is if house built after 2010.

But I think in your case there is a fault with motorised valve, even if they have also made installation errors.