Boiler working overtime (vailant pump overrun)

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We had a vailant system boiler installed a few months back and it's been bugging me that it seemed to be on when not necessary

Now, it's 27 degrees, we have no hot water call since a few hours back, no heating call yet I can still hear it chugging away

Screen just shows a timer or nothing when I check and it does eventually stop

But what's going on? If I'm not asking for anything then shouldn't it be silent / off


Edit.
Here's where my head is at now (per last post)

- I'm not convinced the wiring is correct
- I think what's happening is that the thermostat in the water tank is detecting drop in temp and telling the boiler it wants more heat
- The boiler has an off / on defined by the thermostat hub (Drayton Wiser) which is saying that the hot water isn't needed.
- Because the wiring isn't quite right its therefore getting a call for heat from the local tank thermostat but nowehere to push it as the 'hot water' is off. This is causing it to go into pump overrun to dissipate that heat

Is this even possible? It's a vailant ecotec
 
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I have a similar issue with my combi.

The rad symbol flashes the boiler is cycling and pump operating, despite no heat being calledd this has gone on for 5 months since installation as i though that was norm. Its not norm, it was installed with a crappy difficult to use basic salus stat which is the cause, i switched off the receiver and hey presto problem solved. This will be ok until winter or i work out how to use the crappy stat.

I'm pretty clued up with efficiency and all that jazz and will most probably have to replace the stat i can actually use.

You should first read the boiler manual as it may have pointers to your boiler maybe having a preheat function but if you have a system boiler then i suspect its heating the water as its supposed to as you have a tank.

If its still an issue best to call your installer as its their job to explain to you how it works
 
I have a similar issue with my combi.

The rad symbol flashes the boiler is cycling and pump operating, despite no heat being calledd this has gone on for 5 months since installation as i though that was norm. Its not norm, it was installed with a crappy difficult to use basic salus stat which is the cause, i switched off the receiver and hey presto problem solved. This will be ok until winter or i work out how to use the crappy stat.

I'm pretty clued up with efficiency and all that jazz and will most probably have to replace the stat i can actually use.

You should first read the boiler manual as it may have pointers to your boiler maybe having a preheat function but if you have a system boiler then i suspect its heating the water as its supposed to as you have a tank.

If its still an issue best to call your installer as its their job to explain to you how it works

It's only set to heat the water in the tank twice a day so know it's not (or shouldn't be) doing that

The display changes when it's heating the water too so if it is doing (or trying to) that it's doing it in some way that the display can't recognize
 
Here's what I think is going on... (pure speculation):
- I'm not convinced the wiring is correct
- I think what's happening is that the thermostat in the water tank is detecting drop in temp and telling the boiler it wants more heat
- The boiler has an off / on defined by the thermostat hub (Drayton Wiser) which is saying that the hot water isn't needed.
- Because the wiring isn't quite right its therefore getting a call for heat from the local tank thermostat but nowehere to push it as the 'hot water' is off. This is causing it to go into pump overrun to dissipate that heat

Is this even possible?
 
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Is this even possible?
When I had a new Vaillant heat only boiler (EcoTEC plus 418) fitted a couple of years ago, I had the same symptoms as you on the very first night - constantly circulating the water even though both thermostats were turned right down. I even turned the heating and hot water controls off but it still ran. While I was waiting for the installer to return the following day, I called Vaillant. Before I had even finished describing my fault, they stopped me and asked if I had Vaillant controls. When I said I didn’t he said "They’ve not removed the 24v link inside the boiler". I told him it was a Vaillant approved installer and he just said they all forget to do it. He told me Vaillant controls are 24 volts and if you use any other makes you just have to remove a small link inside the boiler. I removed mine myself and it was all good from then on. Perhaps that’s your problem?
 
When I had a new Vaillant heat only boiler (EcoTEC plus 418) fitted a couple of years ago, I had the same symptoms as you on the very first night - constantly circulating the water even though both thermostats were turned right down. I even turned the heating and hot water controls off but it still ran. While I was waiting for the installer to return the following day, I called Vaillant. Before I had even finished describing my fault, they stopped me and asked if I had Vaillant controls. When I said I didn’t he said "They’ve not removed the 24v link inside the boiler". I told him it was a Vaillant approved installer and he just said they all forget to do it. He told me Vaillant controls are 24 volts and if you use any other makes you just have to remove a small link inside the boiler. I removed mine myself and it was all good from then on. Perhaps that’s your problem?

Interesting. Do you happen to have a pic of where it is? We don't have vailant controls

We had a lot of back and forth on the wiring as we had all sorts of issues getting it working with any kind of hot water control, so it wouldn't surprise me if something like that had been omitted
 
Interesting. Do you happen to have a pic of where it is? We don't have vailant controls

We had a lot of back and forth on the wiring as we had all sorts of issues getting it working with any kind of hot water control, so it wouldn't surprise me if something like that had been omitted
This was where it was on mine - not sure what model you have but it will be in the online installation manual for your model. I just removed the 24v link.

BCCFCBC4-42E4-438D-B33E-65879B794A13.jpeg
 
This was where it was on mine - not sure what model you have but it will be in the online installation manual for your model. I just removed the 24v link.

View attachment 194216
Thank you

Mine is an Exclusive 627.
It's been a nightmare since day 1 in so many ways!

Will take a look at the manual and see if might be something similar... And get the installer back
 
Sadly doesn't look like there's anything 24v mentioned in the manual ☹️
 
Your boiler has a 24v plug on the pcb as already said, get the installer back to remove it.
 
Looking at an online picture of the PCB, this is where it is.

View attachment 194218

Awesome! Thanks
And just to confirm, what would happen if it _were_ supposed to be there?
I'm not convinced that my installer won't just rip it out if I tell him, and I don't want there to be a major downside!
 
As far as I know, Vaillant controls are 24v. If using other makes, the link has to be removed. That’s the limit of my knowledge I’m afraid. If your controller is 240v, it shouldn’t be there, that’s what I was told by the Vaillant tech guy. Might be worth seeing if it has been removed first.
 
Awesome! Thanks
And just to confirm, what would happen if it _were_ supposed to be there?
I'm not convinced that my installer won't just rip it out if I tell him, and I don't want there to be a major downside!

Upload a photo of your board.
Disconnecting it won't do anything apart from make it work. It's not meant to be there if using 240v controls.
 
Upload a photo of your board.
Disconnecting it won't do anything apart from make it work. It's not meant to be there if using 240v controls.

Will do when I can get up to it.
I'm not sure why it would be working at all if it were in place tho?
 

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