Hi All,
I've viewed the forum a lot recently but this is my first actual posting. I'm hoping someone can shed some light on this, though I can't find anything similar posted previously.
We have a brand new Vaillant-based system which was recently installed as part of a house refurbishment, but which we now realise is not working as it should. I suspect there may be more than one problem interacting, just to make life more difficult.
For various reasons we have long lost faith in the builders responsible, but I'd like to do some basic checks before going to a 3rd party picked at random from Vaillant's website, particularly as it doesn't seem a common set of symptoms. I can't touch anything myself and still hold the builders accountable.
the system is
Vaillant ecoTec Plus 630 boiler
VR65 Control centre
VRC470 weather compensator
Thermastor horizontal unvented cylinder.
It's plumbed as (I think) a Y, that is to say a single flow split in two with two, 2-way valves for CH and HW. The HW cyclinder has a variable thermostat which is wired into the VR65. We have not used the HW temp sensor supplied with the VR65.
HW is fine, maybe not as hot as I'd like but the tank thermostat is 70 max so what we get seems in line with that. The main symptom is that the CH only comes on with the HW, and at HW flow temperatures (which is to say 70+; scaldingly unsafe for my toddler....)
Note: the tank also has immersion heaters. The switch for these is unlabelled for on/off.....
The secondary issue is that whilst the VRC470 is internally "correct", and it and boiler are clearly "talking" on the eBus (more details below), the boiler does not acknowledge the VRC470 thermostat.
In more detail:
Boiler is at factory defaults throughout. I've varied a lot on the VRC470 but manually set it back to at or close to factory settings.
Boiler D.090 "Digital Controller Status" is "1.Recognised"
The VRC470's display of internal and outside temperatures are correct (or at least "reasonable"..). Boiler D.047 shows this same outside temperature.
With VRC470 set to "modulating", "Flow Temp target" adjusts appropriately for adjustments to both desired temperature and heating curve. The boiler diagnostics (D.005 and D.009) both reflect this FTT
However.. no amount of adjustment to Desired temperature or Heating timed programs, between "Modulating" and "thermostat" or indeed HW on/off, can get the boiler's thermostat status to shift from D.008 = "0. Open" (no heat requirement), even with target flow temps over 50 deg C. [summer offset is 0K, heat curve 2.25]
When the HW (and rads...) are on, the 470 shows Heat Generator Status as "DHW".
Finally, whilst HW is on and most rads open and warming up, Flow (D.040) is at 63 and return (D.041) at 45.
So I suspect it's some variation of:
1. Obscure Electronic setting, incompatibility, or outright fault preventing the CH thermostat coming on
2. Plumbing, mechanical, or wiring fault in the CH and/or DHW valves (possibly valve DHW and CH wiring in the VR65 inverted and immersions are providing HW ??)
(2) seems solvable in both the detecting and fixing sense, but does it sound like a reasonable diagnosis?
1. is just.. weird. the controller and boiler are clearly talking on the bus, and the controller clearly tells the correct temperature. VR65 was specifically recommended by Vaillant tech support for this install.
Many thanks
Miles
I've viewed the forum a lot recently but this is my first actual posting. I'm hoping someone can shed some light on this, though I can't find anything similar posted previously.
We have a brand new Vaillant-based system which was recently installed as part of a house refurbishment, but which we now realise is not working as it should. I suspect there may be more than one problem interacting, just to make life more difficult.
For various reasons we have long lost faith in the builders responsible, but I'd like to do some basic checks before going to a 3rd party picked at random from Vaillant's website, particularly as it doesn't seem a common set of symptoms. I can't touch anything myself and still hold the builders accountable.
the system is
Vaillant ecoTec Plus 630 boiler
VR65 Control centre
VRC470 weather compensator
Thermastor horizontal unvented cylinder.
It's plumbed as (I think) a Y, that is to say a single flow split in two with two, 2-way valves for CH and HW. The HW cyclinder has a variable thermostat which is wired into the VR65. We have not used the HW temp sensor supplied with the VR65.
HW is fine, maybe not as hot as I'd like but the tank thermostat is 70 max so what we get seems in line with that. The main symptom is that the CH only comes on with the HW, and at HW flow temperatures (which is to say 70+; scaldingly unsafe for my toddler....)
Note: the tank also has immersion heaters. The switch for these is unlabelled for on/off.....
The secondary issue is that whilst the VRC470 is internally "correct", and it and boiler are clearly "talking" on the eBus (more details below), the boiler does not acknowledge the VRC470 thermostat.
In more detail:
Boiler is at factory defaults throughout. I've varied a lot on the VRC470 but manually set it back to at or close to factory settings.
Boiler D.090 "Digital Controller Status" is "1.Recognised"
The VRC470's display of internal and outside temperatures are correct (or at least "reasonable"..). Boiler D.047 shows this same outside temperature.
With VRC470 set to "modulating", "Flow Temp target" adjusts appropriately for adjustments to both desired temperature and heating curve. The boiler diagnostics (D.005 and D.009) both reflect this FTT
However.. no amount of adjustment to Desired temperature or Heating timed programs, between "Modulating" and "thermostat" or indeed HW on/off, can get the boiler's thermostat status to shift from D.008 = "0. Open" (no heat requirement), even with target flow temps over 50 deg C. [summer offset is 0K, heat curve 2.25]
When the HW (and rads...) are on, the 470 shows Heat Generator Status as "DHW".
Finally, whilst HW is on and most rads open and warming up, Flow (D.040) is at 63 and return (D.041) at 45.
So I suspect it's some variation of:
1. Obscure Electronic setting, incompatibility, or outright fault preventing the CH thermostat coming on
2. Plumbing, mechanical, or wiring fault in the CH and/or DHW valves (possibly valve DHW and CH wiring in the VR65 inverted and immersions are providing HW ??)
(2) seems solvable in both the detecting and fixing sense, but does it sound like a reasonable diagnosis?
1. is just.. weird. the controller and boiler are clearly talking on the bus, and the controller clearly tells the correct temperature. VR65 was specifically recommended by Vaillant tech support for this install.
Many thanks
Miles