Operation of the VRT360 and VRT360f Controllers with ecoTEC plus Boilers.
I have realized from correspondence here and elsewhere that operation and limitations of the Vaillant VRT360/360f controllers, when used in conjunction with the VR65 interface, a cylinder thermostat or VR10 Negative Temperature Coefficient (NTC) cylinder sensor are not fully understood. Appeals to Vaillant for full information fall on ‘deaf ears’, with repeated advice for end user to call their 09068 020 251 number This latter reference without telling you that this number is charged at premium rate which, in this instance, is 60p per minute. (Incidentally, I gather it is illegal to give a premium rate number without advising the cost at the point of publication - which I have also drawn to their attention without success).
The VRT360 operates in an identical manner to the VRT360f. However, the Thermostat and Control unit (transmitter) of the former is hard wired to its associated receiver unit, whilst the latter uses a battery driven wireless link, allowing the positioning of the room thermostat to be more flexible. Henceforth any reference to VRT360 will apply to both versions.
The VRT360 and associated units uses the Vaillant eBUS system to communicate with each other and any Vaillant boiler which incorporates the eBUS system. This is a simple 2-wire, low voltage bus, which can be connected in any size of 2-core cable, from bell wire upwards. Polarity is not a factor and wires can be reversed between units without any effect. My own experience relates to the Vaillant ecoTech plus range (415,418,428 and 438) of open vent boilers, used with the VRT360f
The current (07. 2006) Operating and Installation manual is, in my opinion, very poorly written, not making it clear that three individual time periods can be set for each day, (H1, H2 and H3) and each of these time period can be programmed individually for both Domestic Hot Water (DHW) and Central Heating (CH). In other words, H1 for CH can be set to a different time period to H1 for DHW. This is done at the Control Unit, after initial setting up of the CH time periods in The Installer Level menu. (Page 37 of the manual onwards.) A calendar function, enabling automatic British Summer Time correction can also be enabled in this latter programme level.
VR65 Control Centre
The VR65 provides an interface between the low voltage eBUS signals and 230V mains operated control valves. This unit connects to the mains, via an independently fused spur and is supplied complete with individual dedicated plugs for all external connections. This includes the eBUS wiring to the VRT360 and boiler. Either two 230 Volt 2-port valves or one 3-port valve can be controlled via the unit, but only ‘spring return’ valves can be used, as no switched mains supply is provided to close any Motor On-Motor Off (MO-MO) type valves. The internal valve micro switches are not utilised in either configuration and are therefore left disconnected but isolated.
Installation and Operation using Mechanical DHW Cylinder Thermostat.
If a standard, isolated contact, cylinder thermostat is connected to the VR65 at its appropriate plug terminals (CYL) then much of the DHW control provided by the VRT360 is lost. The boiler DHW control knob is then not utilised by the system, as the boiler has no way of knowing the actual temperature of the stored water. Only a ‘demand’ or ‘satisfied’ signal being available without any reference to the actual set temperature. The operation of the cylinder thermostat is then simply passed by the VR65 to the appropriate motorised valve to open or close in response. Therefore, the required temperature of the DHW is set manually at the cylinder thermostat and cannot be set at the VRT360. Therefore, only time control of the DHW is provided by the VRT360 in this configuration.
In addition, because of the lack of actual temperature information, the special ‘F’ function entitled “Once-only cylinder filling” (accessed by four presses of the ‘F’ button is not available. Therefore the DHW cannot be boosted, when required, but only heated during a pre-programmed time period.
In my opinion, use of this controller offers only one benefit over a simple basic installation for any aspect of DHW control and that is the independent time function.
The aforementioned lack of DHW facilities are not what is implied by the wording of all advertising, and is not made clear in the Operating manual. I would advise that using this controller for control of DHW is inappropriate when using a standard cylinder thermostat.
Installation and Operation using the VR10 with DHW Cylinder
When the VR10 NTC temperature sensor supplied with the VR65 package is utilised, however, the whole system makes sense and operates almost as advertised.
In accordance with the Installation Instructions for the VR65 (Para 5.3), the VR10 is approved for use only with the Vaillant ecoTEC series of boilers. What I think they mean to say, but don’t, is that the VR10 is approved for use with the Vaillant uniSTOR . This is emphasised in both Control Centre connection diagrams (Fig 5.2 and 5.3) in the aforementioned instruction book. With the VR10 fitted to the uniSTOR then all DHW control functions are now operative, with DHW temperature set at the VRT360 and boiler control of max DHW temperature is now operative. The ‘F’ function entitled “Once-only cylinder filling” now operates correctly, allowing water temperature to be boosted as required.
In my own case and since there are no specific instructions to the contrary, I have installed the VR10 to a standard domestic indirect cylinder, as the uniSTOR is outside my price range and the existing DHW cylinder is reasonably new. This I did as follows:
Using any suitable item, (a 4mm drill bit in my case) carefully remove the insulating foam from the cylinder to form a suitable vertical pocket for the VR10 , ensuring the bare copper of the cylinder is visible for the entire length of the VR10 sensor element. Carefully clean the exposed copper, as required, without damaging the cylinder wall. Apply a small amount of heat sink compound to the sensor (available from Maplin) then hold the sensor in direct contact with the cylinder wall using a small piece of 5mm aluminium or copper tube wedged into the foam on top of the sensor. Whilst supporting the integral eBUS lead, fill the entire excavation with silicone sealer, as used for sealing car windscreens or use Fernox LS-X External Leak Sealer. Clean off any surplus sealer before set then tape in position until the sealer has set. In my experience this method gives a direct equivalent to installing the VR10 in a dry pocket, without all the hassle of fitting an Essex flange . Connect the VR10 to the VR65 at plug terminal NTC, ensuring any connection to the CYL connection is removed.
If any significant disparity is noted between the actual measured water temperature and that required, then this can be simply corrected by adjusting the required set temperature at the VRT360 as required. I have noted no such discrepancy.
I do hope these notes have removed some of the misunderstanding and clarified the use of the VRT360 and VRT360f . With the VR10, the system is fabulous - without it the extra cost over a standard timer and individual thermostats is, in my opinion, just not worth it.
Additional Comments Re-Lack of Simultaneous CH and DHW Facility with ecoTEC plus Boilers.
Just after the last heading I used the phrase “….operates almost as advertised.” I used this specifically because I have found that following the detailed instruction given at paragraph 6 of the VR65 Installation Instruction manual do not alter the operation of the associated motorised valves in any way. The idea is to allow the boiler to heat both DHW and CH simultaneously or independently, as required. The boiler diagnostic menu d.70 is accessed as detailed correctly, and the default setting of ‘0’ is shown. In this setting DHW priority is set, ensuring any demand for DHW causes the CH motorised valve to close until the demand for DHW heating is satisfied.
I accessed d.70, then changed the default to ‘1’, using the + & - keys and then saved the new setting, as detailed, by holding the ‘I’ button for approximately 5 seconds until the display stabilised. This had no effect on the operation of the boiler, each time DHW is demanded, the DHW valve opens and the CH valve closes. Boiler water flow temperature increases to that set at the boiler controller if it exceeds the current set boiler (CH) as expected, but the demand for simultaneous heating and hot water is never achieved. I did check the setting of d.70 later, and ensured it had been stored correctly Again efforts to get comment on this observation from Vaillant have been unsuccessful.
Any comments or experiences you have had with this system please post on this site and then we can have a discussion on how to proceed. I am sure most of these anomalies could be solved with new software, but until they are acknowledged then nothing will be done.
I have realized from correspondence here and elsewhere that operation and limitations of the Vaillant VRT360/360f controllers, when used in conjunction with the VR65 interface, a cylinder thermostat or VR10 Negative Temperature Coefficient (NTC) cylinder sensor are not fully understood. Appeals to Vaillant for full information fall on ‘deaf ears’, with repeated advice for end user to call their 09068 020 251 number This latter reference without telling you that this number is charged at premium rate which, in this instance, is 60p per minute. (Incidentally, I gather it is illegal to give a premium rate number without advising the cost at the point of publication - which I have also drawn to their attention without success).
The VRT360 operates in an identical manner to the VRT360f. However, the Thermostat and Control unit (transmitter) of the former is hard wired to its associated receiver unit, whilst the latter uses a battery driven wireless link, allowing the positioning of the room thermostat to be more flexible. Henceforth any reference to VRT360 will apply to both versions.
The VRT360 and associated units uses the Vaillant eBUS system to communicate with each other and any Vaillant boiler which incorporates the eBUS system. This is a simple 2-wire, low voltage bus, which can be connected in any size of 2-core cable, from bell wire upwards. Polarity is not a factor and wires can be reversed between units without any effect. My own experience relates to the Vaillant ecoTech plus range (415,418,428 and 438) of open vent boilers, used with the VRT360f
The current (07. 2006) Operating and Installation manual is, in my opinion, very poorly written, not making it clear that three individual time periods can be set for each day, (H1, H2 and H3) and each of these time period can be programmed individually for both Domestic Hot Water (DHW) and Central Heating (CH). In other words, H1 for CH can be set to a different time period to H1 for DHW. This is done at the Control Unit, after initial setting up of the CH time periods in The Installer Level menu. (Page 37 of the manual onwards.) A calendar function, enabling automatic British Summer Time correction can also be enabled in this latter programme level.
VR65 Control Centre
The VR65 provides an interface between the low voltage eBUS signals and 230V mains operated control valves. This unit connects to the mains, via an independently fused spur and is supplied complete with individual dedicated plugs for all external connections. This includes the eBUS wiring to the VRT360 and boiler. Either two 230 Volt 2-port valves or one 3-port valve can be controlled via the unit, but only ‘spring return’ valves can be used, as no switched mains supply is provided to close any Motor On-Motor Off (MO-MO) type valves. The internal valve micro switches are not utilised in either configuration and are therefore left disconnected but isolated.
Installation and Operation using Mechanical DHW Cylinder Thermostat.
If a standard, isolated contact, cylinder thermostat is connected to the VR65 at its appropriate plug terminals (CYL) then much of the DHW control provided by the VRT360 is lost. The boiler DHW control knob is then not utilised by the system, as the boiler has no way of knowing the actual temperature of the stored water. Only a ‘demand’ or ‘satisfied’ signal being available without any reference to the actual set temperature. The operation of the cylinder thermostat is then simply passed by the VR65 to the appropriate motorised valve to open or close in response. Therefore, the required temperature of the DHW is set manually at the cylinder thermostat and cannot be set at the VRT360. Therefore, only time control of the DHW is provided by the VRT360 in this configuration.
In addition, because of the lack of actual temperature information, the special ‘F’ function entitled “Once-only cylinder filling” (accessed by four presses of the ‘F’ button is not available. Therefore the DHW cannot be boosted, when required, but only heated during a pre-programmed time period.
In my opinion, use of this controller offers only one benefit over a simple basic installation for any aspect of DHW control and that is the independent time function.
The aforementioned lack of DHW facilities are not what is implied by the wording of all advertising, and is not made clear in the Operating manual. I would advise that using this controller for control of DHW is inappropriate when using a standard cylinder thermostat.
Installation and Operation using the VR10 with DHW Cylinder
When the VR10 NTC temperature sensor supplied with the VR65 package is utilised, however, the whole system makes sense and operates almost as advertised.
In accordance with the Installation Instructions for the VR65 (Para 5.3), the VR10 is approved for use only with the Vaillant ecoTEC series of boilers. What I think they mean to say, but don’t, is that the VR10 is approved for use with the Vaillant uniSTOR . This is emphasised in both Control Centre connection diagrams (Fig 5.2 and 5.3) in the aforementioned instruction book. With the VR10 fitted to the uniSTOR then all DHW control functions are now operative, with DHW temperature set at the VRT360 and boiler control of max DHW temperature is now operative. The ‘F’ function entitled “Once-only cylinder filling” now operates correctly, allowing water temperature to be boosted as required.
In my own case and since there are no specific instructions to the contrary, I have installed the VR10 to a standard domestic indirect cylinder, as the uniSTOR is outside my price range and the existing DHW cylinder is reasonably new. This I did as follows:
Using any suitable item, (a 4mm drill bit in my case) carefully remove the insulating foam from the cylinder to form a suitable vertical pocket for the VR10 , ensuring the bare copper of the cylinder is visible for the entire length of the VR10 sensor element. Carefully clean the exposed copper, as required, without damaging the cylinder wall. Apply a small amount of heat sink compound to the sensor (available from Maplin) then hold the sensor in direct contact with the cylinder wall using a small piece of 5mm aluminium or copper tube wedged into the foam on top of the sensor. Whilst supporting the integral eBUS lead, fill the entire excavation with silicone sealer, as used for sealing car windscreens or use Fernox LS-X External Leak Sealer. Clean off any surplus sealer before set then tape in position until the sealer has set. In my experience this method gives a direct equivalent to installing the VR10 in a dry pocket, without all the hassle of fitting an Essex flange . Connect the VR10 to the VR65 at plug terminal NTC, ensuring any connection to the CYL connection is removed.
If any significant disparity is noted between the actual measured water temperature and that required, then this can be simply corrected by adjusting the required set temperature at the VRT360 as required. I have noted no such discrepancy.
I do hope these notes have removed some of the misunderstanding and clarified the use of the VRT360 and VRT360f . With the VR10, the system is fabulous - without it the extra cost over a standard timer and individual thermostats is, in my opinion, just not worth it.
Additional Comments Re-Lack of Simultaneous CH and DHW Facility with ecoTEC plus Boilers.
Just after the last heading I used the phrase “….operates almost as advertised.” I used this specifically because I have found that following the detailed instruction given at paragraph 6 of the VR65 Installation Instruction manual do not alter the operation of the associated motorised valves in any way. The idea is to allow the boiler to heat both DHW and CH simultaneously or independently, as required. The boiler diagnostic menu d.70 is accessed as detailed correctly, and the default setting of ‘0’ is shown. In this setting DHW priority is set, ensuring any demand for DHW causes the CH motorised valve to close until the demand for DHW heating is satisfied.
I accessed d.70, then changed the default to ‘1’, using the + & - keys and then saved the new setting, as detailed, by holding the ‘I’ button for approximately 5 seconds until the display stabilised. This had no effect on the operation of the boiler, each time DHW is demanded, the DHW valve opens and the CH valve closes. Boiler water flow temperature increases to that set at the boiler controller if it exceeds the current set boiler (CH) as expected, but the demand for simultaneous heating and hot water is never achieved. I did check the setting of d.70 later, and ensured it had been stored correctly Again efforts to get comment on this observation from Vaillant have been unsuccessful.
Any comments or experiences you have had with this system please post on this site and then we can have a discussion on how to proceed. I am sure most of these anomalies could be solved with new software, but until they are acknowledged then nothing will be done.
