ECOtech 418 problem

Robert Tyrrell · Feb 24, 2016

Good morning people,
I've just been called by a customer to tell me that her Vaillant Ecotech 418 (Installed 2013) is constantly firing up. Apparently she sets the programmer and the boiler fires, reaches temperature and stops. The problem is that a couple of minutes afterwards it fires again, even though the set temperature has been reached.
I wondered if any of you have a bright idea as to how this has occurred and can be sorted. I'm not anywhere near the boiler for a couple of days and when I call Vaillant they take sooooo long to answer their phones that it's ridiculous waiting for them.
I've looked on the Internet but can't find much on how to sort it, just descriptions of the fault.

Oh, and one other thing - has anyone heard of a Honeywell DT92E making a squealing noise when not calling for heat? Customer says that they can hear it overtime they're in the kitchen (Where the boiler, programmer, and receiver are located).

Apologies for the multiple threads in this post.

AHA

Chalked · Feb 24, 2016

See if the room stat link is still fitted.

SmokeyJ · Feb 24, 2016

Boiler is only going to respond to a heat demand from something. I'd bet a stuck motorised valve, they override programmer etc when they stick. Dt92e will go into failsafe mode if wireless connection lost but will still need programmer on to fire boiler. If programmer faulty the room stat would still turn the system on and off. Most likely a s plan system. Are you familiar with control wiring?

Robert Tyrrell · Feb 24, 2016

SmokeyJ said:
Most likely a s plan system. Are you familiar with control wiring?

That for the info. I am familiar with wiring systems as in 'S' plan, 'Y' plan etc but not that knowledgeable when it comes to 'Control' wiring - if you mean what wire does what etc.
I know that on the 3 way valve the White wire and the grey wire do the main work in terms of calling for heat via the room stat.
BTW - it's a 'Y' plan and I've already changed the actuator. Might just be that the valve body is sticking then 🙂

SmokeyJ · Feb 24, 2016

Ahh if its a 3 port and wired right that shouldn't occur. Only way for orange (CH switch live) to become live is if you have power on white and grey meaning ch on and hw off. Therefore must have a demand from elsewhere, would rule out valve. It may be the thermostat, red light on receiver means loss of communication. Receiver can be overridden with green button but not sure if it is only temporary till next off period or a constant thing till button next pushed? I've called honeywell before, very helpful. Dt92e instructions I found confusing.
I'm a bit rusty with 3ports so excuse me if i'm wrong.

Robert Tyrrell · Feb 25, 2016

The thing is that it was working, I was called to a fault where the heating had stopped working but the water was fine. I found that the Salus wireless room stat had failed (No signal, even with new batteries) and I replaced that only to find that the actuator had gone as well (No power on white or grey). I left it working fine for heat but then 48 hours later she calls me to say that the DT92E is making a 'Squealing' noise, and that the heating comes on, reaches temperature, goes off and then comes back on after about 3 minutes even though there's no demand from the room stat.
I realise it's probably two different problems but I'd like to know what's causing them.
Imaging to attend today and call both Vaillant and Honeywell while I'm there.

c.gas · Feb 25, 2016

Let us know how you get on rob, would like to know what the solution is

Robert Tyrrell · Feb 25, 2016

Right - I called Vaillant, and went through the standard logic finding process and they say that there's nothing wrong with the boiler. The guy tried to explain how a heating system linked to a thermostat worked (WT*).
I checked th room stat and I've noticed that it will fire the boiler, or shut it down because of a 0.5 degree temperature change. Is this normal? I though that it would be at least 5 degrees. If this is normal, does anyone have a chart or similar that can tell me the average drop in room temperatures over a given period? The customer is saying that it reaches temp at the RS and the boiler shuts down but then 3 minutes later it will fire again - this continues as long as the boiler is in heating mode.
The flow temp differential is correct according to Vaillant btw.
I tried calling Honeywell to discuss the stat but couldn't get through as the number just causes a Roadrunner and then nothing. Anyone got a number for Honeywell tech dept?
Off to kenjutsu training now 🙂

Leo21 · Feb 25, 2016

I've had this, I changed the dv valve wiring without fitting th valve. It did the same thing, I wired the old valve back in and it stopped! They haven't called back, so it's fixed.
Have you checked the wiring in the boiler?

Robert Tyrrell · Feb 26, 2016

Thanks Leo21. Can you please answer the following for though?

I changed the dv valve wiring without fitting th valve

Why did you change the wiring? I changed my wiring because the actuator was being swapped out - like for like, and the wires were swapped out one at a time.

I wired the old valve back in and it stopped

Do you mean you put the old actuator back on? That isn't a solution or me as the actuator has definitely packed up.

Have you checked the wiring in the boiler?

Why would I need to do this as everything was working beforehand? The system is set up as a Honeywell 'Y' plan with a 10 way junction box in the cylinder cupboard and I wired the actuator to that.

Leo21 · Feb 26, 2016

I wired the dv in with wiring only. I didn't drain the system and fit the body.
The reason I put the old one back on was because it didn't cure the fault.
You need to check the wiring to make sure if it's a boiler fault or system fault.
If you've got live to switch live, it's a system/wiring fault. If you haven't got live there it's a boiler fault, using the permanent live to fire the boiler of its own accord.
The fault rectified itself, it just stopped! And you can't failure find when it's working!