Discuss HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT360) in the Central Heating Systems area at ElectriciansForums.net

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harpss1ngh

Hi I'm having issues with my hot water valve which remains on all day until the vrt360 goes on standby at night.


Quick breakdown of my setup as follows:


Vaillant ecoTEC 637 system boiler w/eBUS
VR65 Control Center via eBUS
VRT360 Controller via eBUS
2-port valve for HW wired to VR65 using E/N/L wires only on the Purple DHW terminal
2-port valve for CH wired to VR65 usinng E/N/L wires to the CH terminal
1 extra pump wired to the CH terminal on the VR65 (due to large extended house with lots of radiators)
Cylinder with analogue thermostat w/manual temp dial wired to CYL on the VR65


I have checked all electronic wiring which appears to be correct.




I have tried changing the d.70 diverter valve position setting on the boiler between 0 and 1 to see if it makes any difference to the HW valve behaviour, but no luck.


When set to 0, if a CH request is received, the VR65 turns off the HW valve and turns on the CH valve. But when the CH goes off, the HW turns back on.


When set to 1, if a CH request is received then CH and HW both stay on, or the HW stays on all the time.


Due to the HW valve always being on, this causes issues with the Central Heating either not coming on, or taking longer than usual to warm the radiators


I have set the boiler to factory settings.




If I turn down the CYL thermostat (and hear the click of the thermostat going off), the HW valve doesn't go off. Multimeter shows 230v voltage is still being fed on the HW terminal.


The CH seems fine as if I turn up the thermostat on the VRT360, the valve turns on, and if I turn it down the valve responds correctly and turns off.

The valves are brand new and are Honeywell branded.

Could this indicate the VR65 is faulty? Am I better off replacing it with the newer VR66 and VRT350 combo?
 
Re: HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT3

Have you looked at the LED display in the VR65 unit when turning system on & off as looking at the vaillant tech book if it's perm on during operations it should be fine, led flashes quickly normally shows a fault DHW circuit NTC probe short circuit, (if using).
Led flashes slowly this would indicate a bus fault.
Just pulled from tech page
 
Re: HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT3

If the Vaillant control / wiring centre is the same as the Gloworm, which I suspect it is, then they are a pile of junk.
The relays on the circuit are the first thing to give up - it sounds like yours has stuck closed.

I've took out at least 5 of these unreliable wiring centres and replaced them with conventional prgrammers and room stats.
I'd suggest you do the same, as the price is similar to a new wiring centre, and you know if one component breaks in future, it is an easy fix.
 
Re: HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT3

Have you looked at the LED display in the VR65 unit when turning system on & off as looking at the vaillant tech book if it's perm on during operations it should be fine, led flashes quickly normally shows a fault DHW circuit NTC probe short circuit, (if using).
Led flashes slowly this would indicate a bus fault.
Just pulled from tech page

Thanks for the reply, that's the first thing I checked. The LED is solid green but nevertheless it is still possible that it's faulty.
 
Re: HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT3

If the Vaillant control / wiring centre is the same as the Gloworm, which I suspect it is, then they are a pile of junk.
The relays on the circuit are the first thing to give up - it sounds like yours has stuck closed.

I've took out at least 5 of these unreliable wiring centres and replaced them with conventional prgrammers and room stats.
I'd suggest you do the same, as the price is similar to a new wiring centre, and you know if one component breaks in future, it is an easy fix.

Thanks for your reply.

I thought so too but the strange thing is that when the programmer shuts off the valve's at night (as programmed it to do so), both valves do get shut off at midnight.

In fact they're both off now. So if it was stuck on, wouldn't it be stuck on all the time? If I set the diverter valve position setting to 0 and a central heating request is made, the hot water valve shuts off and the central heating one opens. So it can open and shut properly (according to that anyway) but seems to have a mind of its own.

I've checked the cylinder thermostat using a multimeter in continuity mode and it's definitely working correctly so one would assume the hot water valve would respond accordingly.

It's been running fine for a good 10 years or so, except for the last few months.
 
Re: HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT3

Hi,

I replaced the VR65 and VRT360 with a VR66 (set to VR65 mode/Position 1 on the switch inside) and a VRT350. Everything works as I expected and the valve switches off properly now. The VR66 is a new replacement for the VR65 which is now obsolete so hopefully should get plenty of use from it, assuming they improved the design. Also, the VRT350 is a much nicer controller and much easier to use.

Thanks all
 

Reply to HW valve stays on all the time, never switches off (Vaillant ecoTEC 637/VR65/VRT360) in the Central Heating Systems area at ElectriciansForums.net

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