Heating off but radiators warm.... (EvoHome issue)

[mondeoman]

Now that summer is here (finally) I've set the Central Heating to Off, but I've got a couple of radiators that are getting hot.

They are on the Central Heating circuit, but don't have individual stats (HR92s) fitted yet. Those with HR92s are nice and cold.

What I have noticed is that both of the BDR91s (hot water and central heating) are showing a green light when the Hot Water is timed to be on.

Is this a simple re-pairing or is it possibly something more serious? Are there any simple tests that I can do to check before I dive into re-wiring everything. It was installed in the winter, so until now if there was a fault it would've been masked by the fact that the CH and HW were on at the same time.

[top brake]

Now that summer is here (finally) I've set the Central Heating to Off, but I've got a couple of radiators that are getting hot.

They are on the Central Heating circuit, but don't have individual stats (HR92s) fitted yet. Those with HR92s are nice and cold.

What I have noticed is that both of the BDR91s (hot water and central heating) are showing a green light when the Hot Water is timed to be on.

Is this a simple re-pairing or is it possibly something more serious? Are there any simple tests that I can do to check before I dive into re-wiring everything. It was installed in the winter, so until now if there was a fault it would've been masked by the fact that the CH and HW were on at the same time.

Sounds like it could be a simple binding issue but to be sure can you explain a bit more about how your relays are wired?

Is the boiler wired from the motorised valve aux switch (orange wires)?

[mondeoman]

Assuming I wired everything correctly, then it's wired as a standard S plan eg two x 2-way valves, so the boiler and pump are fed via the Orange wires.

[top brake]

Assuming I wired everything correctly, then it's wired as a standard S plan eg two x 2-way valves, so the boiler and pump are fed via the Orange wires.

Cool

So go into installer menu, system devices

Remove heat demand relay

Go to guided configuration

Ignore warning

Select lower button hot water

Follow instructions on screen and in manual

Exit to home screen

That's all

But please do the full youlearn so that you understand why, what and how

[paulockenden]

Top Brake - If the heating relay is double bound (i.e. the 'in the box' boiler relay binding is still present), isn't it worth clearing that too, on the BDR91 itself?

I know that before I did that my heating relay would come on whenever there was demand from the hot water.

P.

[mondeoman]

So is it best to clear all the binding for the CH system and start again?

[paulockenden]

All I can say is that it's what worked for me. It's quite a long press to clear the binding - can't remember, but something like 10 or 15 seconds.

[top brake]

Top Brake - If the heating relay is double bound (i.e. the 'in the box' boiler relay binding is still present), isn't it worth clearing that too, on the BDR91 itself?

I know that before I did that my heating relay would come on whenever there was demand from the hot water.

P.

the instructions in the manual include to clear existing binding then bind

[mondeoman]

Thank you gentlemen, that seems to have fixed the problem. A few heart-stopping moments after re-binding the two BDR91-s when the hot water didn't come back on, then realised that I had to reset the target temperature. Seems to be working OK now, heating and hot water are working independently of each other.

[SteveP]

Hi, I appear to have a similar issue as I have noticed a few times one radiator that doesn't have a rad controller on it and just has a TRV being warm. I couldn't work out why and checked all other rads and they were cold. I had the main controller set to economy. Yesterday I noticed the green light on the BDR91 was on and yet no zones were calling for heat. So I set the controller to "Heating off" and today saw the BDR91 showing the green light on again and the central heating running. I have now set the central heating on the boiler itself to off but am baffled as to why the BDR91 keeps randomly turning on. It is a combi system so I only have the BDR91 set to run central heating. Any advice appreciated. Thanks

[roydonaldson]

How is your Hot Water configured ? I had the exact same issue and found that I had my heating set as Boiler Relay, and in fact my Hot water was using this to turn the boiler on, but of course, it also turned on the BDR91's that were set for the heating too.

[SteveP]

How is your Hot Water configured ? I had the exact same issue and found that I had my heating set as Boiler Relay, and in fact my Hot water was using this to turn the boiler on, but of course, it also turned on the BDR91's that were set for the heating too.

Hi, as the boiler is a combi, I don't have the hot water control part configured. I have one BD91 and that is set as Boiler relay with no valves. Therefore, no hot water control shows on the system. So I cannot see the hot water control running but maybe it is hidden ? I have checked the installer system configuration and cannot see any reference to hot water.

[paulockenden]

Sounds to me like a problem with your diverter valve (in your combi boiler). If the rubber perishes you get two symptoms, 1) water not as hot as it should be, and 2) rads get warm with the hot water.

Shouldn't be too expensive to fix, but probably needs an engineer.

Nothing to do with Evohome, though.

P.

[SteveP]

Sounds to me like a problem with your diverter valve (in your combi boiler). If the rubber perishes you get two symptoms, 1) water not as hot as it should be, and 2) rads get warm with the hot water.

Shouldn't be too expensive to fix, but probably needs an engineer.

Nothing to do with Evohome, though.

P.

Hi Paul, the combi is working fine. The issue is that the BDR91 randomly calls for heat (green led on the BDR91 lights up) even though the Evohome controller is set to Heating off. That's the baffling part. I originally had the old monochrome controller for 2 years and replaced it with the new colour one September last year. Everything has been working fine but it is only this summer with the new colour controller that I have noticed this odd behaviour. Shame the system doesn't advise which of the 9 zones is calling for heat, that way I would be able to at least narrow down the problem.

[paulockenden]

Ah - apologies then - I'd misunderstood the symptoms that you posted.

P.