You may be waiting a while, given the time of year and the fact that many companies have understaffed offices etc at the moment due to covid.
What questions have you got and I'll try answer some in the meantime?
Yes, they have usually been reasonably quick in the past. I did wonder if the delay may also be due to the number and "complexity" of my questions, especially as they seem to be giving me/my installer conflicting information, which I'm still waiting for them to clarify.
It's very kind of you to offer to help answer my questions, so I'll include the more straight forward ones below, to avoid having to give you lots of background information about my system.
1. What is the difference between:
a) Circulation Pump
b) External Pump
c) Storage Charge Pump
As defined in the
installation instructions for the VR 40. (I tried to attach a pdf of this manual, but kept getting a security error, so have included a link to the manual instead).
I now understand that a "Storage Charge Pump" is a pump for the cylinder only i.e. pumping water "TO" the cylinder. Still not sure of the difference between a) and b). My new Grundfos pump is obviously external to the boiler, but isn't it also a circulation pump i.e. it pumps the flow around the system?
2. Why does the VR 71 wiring centre constantly make a clicking sound? It’s like there is a relay constantly opening and closing. This happens irrespective of the zone valves opening/closing i.e. when I know there is a demand or no longer any demand from one of the zones. Is this constant clicking normal?
3. What should the values of the following boiler parameters be set to:
a. d.75 (currently set to the default of 45 mins)
b. d.77 (currently set to the default of 37kW). Should this be lower?
c. d.78 (currently set to 80 deg C)
d. Are there any other settings I need to be aware of that could possibly cause the hot water cylinder to take so long to heat up?
4. Can you tell me the minimum output of the ecoTEC 637 plus system boiler?
5. On the VRC 700, when programming times, I have the option to program each heating zone (radiators, UFH1, UFH2), DHW and “Circulation Pump”. What exactly does the “Circulation Pump” program control? Is this the internal boiler pump or does it relate to the newly added Grundfos pump (I suspect neither)? I believe this was also available as an option on my old VRC 430.
6. There are two dials on the front of the boiler; the top one for hot water temperature and the bottom for heating temperature. As these dials are turned, the boiler display shows the adjusted temperature setting. In the VRC 700 configuration menu there are MANY temperature settings shown, some of which can be changed, some of which are for information only. Which VRC 700 menu items relate to the boiler dials i.e. hot water temperature and heating temperature? For example, on the VRC 700, in the Desired temperatures, DHW circuit menu, I can set the desired Domestic hot water temperature (currently set to 55 deg C), however, this value does not match the hot water temperature shown on the boiler, when the top dial is changed! For the bottom dial used to change the heating temperature on the boiler, I don't know which VRC 700 menu options relate to this, if any.
So, it would appear the VRC 700 must be used to set the desired temperatures, so what is the relevance of the temperatures set on the boiler using the dials? Should they be matched i.e. changed on both the boiler and VRC 700? Is this an example of the VRC 700 not being completely integrated with the 10 year old ecoTEC 637 plus system boiler?
7. On the VRC 700, in the Configuration menu under DHW circuit, is a menu called Buffer cylinder, which has two options; Cyl temp top and Cyl temp bottom. On my system, only the Cyl temp top ever has a value.
a. From where does it get this value as there is only one cable (the temperature sensor) running from the cylinder and I assume this cable,
which is wired into S9 on the VR 71, provides the current cylinder temperature?
b. Why does the Cyl temp bottom never have a value (it always shows “---“)?
8. There are a number of temperature sensors that were installed along with the VR 71 wiring centre and these are attached as follows:
a) S1 - system flow side of LLH.
b) S2 - on flow pipe immediately after zone valve for zone 1 (Radiators).
c) S3 - on flow pipe immediately after zone valve for zone 2 (Kitchen UFH).
d) S4 - on flow pipe immediately after zone valve for zone 3 (Bathroom UFH).
e) S9 - cylinder temperature probe.
It would appear (as already mentioned in 7a above) the reading for the cylinder temperature probe is shown as the "Current cyl. temp." option of the DHW circuit menu under System Configuration, so I can see at any time what the cylinder temperature is.
Where are the other sensor values reported in the VRC 700 menu system? Are these sensors used for anything i.e. calculating target temperatures, or are they just for information only?
My other questions relate to the way in which the new Grundfos "system pump" has been wired and I've had conflicting responses from Vaillant, so I won't include these questions for now.
Any answers would be useful as I'm trying to understand how the new controllers/wiring centre and the old boiler are working.