Vaillant VRT 360 controls. help needed

[arlester]

I a VRT 360 (same instructions as 360F) and have read the forums and handbook back to front and inside out. Theres 2 controls I just cant understand: Within the installer level you can set the 'SET-BACK TEMPERATURE'. What is it and what effect will it have? 2nd: You can set the 'CONTROL CHARACTERISTICS / ROUTE ADJUSTMENT' In practical terms, a negative setting makes the boiler cut in and out frequently (faster reaction speed of room thermostat), A positive setting causes the boiler to stay on for much longer BUT far less frequently (slower reaction of the room thermostat). Whilst I understand the effect I don't understand how this effects the performance and suitability of my configuration. I have a 4 bedroom house with 17 'old school' column radiators. The house has very high ceilings and is an older (Victorian) cold house. Unbelievably it seems no body at Vaillant understands these controls or there effects. I've had various issues which result in an engineer attending and anouncing 'I've no idea, I'll just order a replacement'. I've spent fortunes on the 'helpline' again to no avail. Any help would be greatly appreciated especially during this cold winter.

 

[jackthom]

As far as I can make out, the SETBACK TEMPERATURE is the minimum room temp that the system will maintain at times when the heating is in timer mode and is supposedly OFF, eg overnight.

Out of the box I believe this is set to 15C and in normal timed operation the house won't ever be allowed to fall below this temp.

 

[jackthom]

The CONTROL CHARACTERISTICS setting looks to me like a variable hysteresis control. The more hysteresis the wider will be the difference in temperature between the thermostat switching OFF/ON and the longer will be the time intervals the boiler will spend either running or off.

There is also an TWO POINT/ANALOG OPERATION setting which when in analog should modulate the heating water temperature according to how far from the target temparature the room is. So initially the boiler would supply very hot water until the room approached the required temp and gradually reduce the radiator temperatures to just maintain that temp.

 

[D_Hailsham]

Within the installer level you can set the 'SET-BACK TEMPERATURE'. What is it and what effect will it have?

That's the night time temperature, also the temperature when the house is unoccupied.

You can set the 'CONTROL CHARACTERISTICS / ROUTE ADJUSTMENT'

I think this is supposed to compensate for the rate at which your house heats up and cools down. If you have a well insulated house which retains heat, you can afford to have a wider spread between on and off temperatures.

Leave it at 0 and watch how the house temperature varies. If it fluctuates too much, try setting to -1. It's a case of experimenting.

 

[arlester]

Within the installer level you can set the 'SET-BACK TEMPERATURE'. What is it and what effect will it have?

That's the night time temperature, also the temperature when the house is unoccupied.

You can set the 'CONTROL CHARACTERISTICS / ROUTE ADJUSTMENT'

I think this is supposed to compensate for the rate at which your house heats up and cools down. If you have a well insulated house which retains heat, you can afford to have a wider spread between on and off temperatures.

Leave it at 0 and watch how the house temperature varies. If it fluctuates too much, try setting to -1. It's a case of experimenting.

Thanks for the prompt replies. Very impressive!! So having spent a long time previously trying to fathom out the best settings, i've found that as I have allot of radiators, 2 of which take longest to get hot (incorrectly plumbed. There under a bay and feed into each other rather than separate supply nto each) I get hotter radiators when the boiler is running for longer, pulling the water through all the radiators within the system. When the boiler is set onto a negative setting the boiler cuts on and off so frequently that the water never seems to get to the 'difficult' radiators. i've balanced the system right down with most of the rad's on a 1/4 to 1/2 turn and thats the only way to force water into the offending rads. I suppose I've answered my own question.

 

[D_Hailsham]

So having spent a long time previously trying to fathom out the best settings, i've found that as I have allot of radiators, 2 of which take longest to get hot (incorrectly plumbed. There under a bay and feed into each other rather than separate supply into each)

Do you mean the two rads are in series, the return from the first is connected to the flow of the second? Or do you mean that one rad has its flow and returns teed off the flow and return of the other?

The first method is dodgy as one rad will affect the other. The second method is OK, provided the pipes which are common to both radiators is of sufficient size to carry the combined heat load.

I've balanced the system right down with most of the rad's on a 1/4 to 1/2 turn and thats the only way to force water into the offending rads. I suppose I've answered my own question.

1/4 to 1/2 turn (I hope you mean from closed) is close, but it may need to be even less. Compared to the flow through the main pipes, the flow through a radiator is very small, so the LS valve has to be almost closed to have any real effect.

What method did you follow when balancing the rads?

 

[arlester]

So having spent a long time previously trying to fathom out the best settings, i've found that as I have allot of radiators, 2 of which take longest to get hot (incorrectly plumbed. There under a bay and feed into each other rather than separate supply into each)

Do you mean the two rads are in series, the return from the first is connected to the flow of the second? Or do you mean that one rad has its flow and returns teed off the flow and return of the other?

The first method is dodgy as one rad will affect the other. The second method is OK, provided the pipes which are common to both radiators is of sufficient size to carry the combined heat load.

I've balanced the system right down with most of the rad's on a 1/4 to 1/2 turn and thats the only way to force water into the offending rads. I suppose I've answered my own question.

1/4 to 1/2 turn (I hope you mean from closed) is close, but it may need to be even less. Compared to the flow through the main pipes, the flow through a radiator is very small, so the LS valve has to be almost closed to have any real effect.

What method did you follow when balancing the rads?

pleased to say second method BUT the radiators are column style rad's so very inefficient and take along time for the water to work through.
As for balancing the rads I had them professionally balanced at the same time as a powerflush. I observed all rads turned off, then one by one (first on run first) turned on and using clip on thermometers, adjusted flow and return until difference was 12degrees (I think, don't quote me). unfortunatly, althought I know this is the text book way, it just didn't provide any heat through the bay rads x 3 and the rad furthest away. It was like the boiler would fire up, pull the hot water through the run of rads and just cut out before it managed to fulfill the awkward ones. If I (just for arguments sake) turned the thermostat to 30, they would eventually get hot but only once the rest of the house was unberable. thats why I eventually (having noted down the original number of turns) decided to try and force the water into the others by turning them all down bar the awkward ones. Works a treat now. Interesting however what you say that anything less than circa 1/2 turn and they might as well be open fully. Thanks again. Great to know there are actually logical people out there who truly undertsand these things.

 

[D_Hailsham]

As for balancing the rads I had them professionally balanced at the same time as a powerflush. I observed all rads turned off, then one by one (first on run first) turned on and using clip on thermometers, adjusted flow and return until difference was 12degrees (I think, don't quote me).

12 degrees sounds about right, though modern condensing boilers are designed for a 20 degree differential.

Because of the interaction between radiators it is normal to have to go round several times before you get the balancing right.

It just didn't provide any heat through the bay rads x 3 and the rad furthest away. It was like the boiler would fire up, pull the hot water through the run of rads and just cut out before it managed to fulfill the awkward ones.

Sounds as if the balancer only went round once!

If I (just for arguments sake) turned the thermostat to 30, they would eventually get hot but only once the rest of the house was unbearable.

Thermostatic valves would help.

Interesting however what you say that anything less than circa 1/2 turn and they might as well be open fully.

1/2 turn is a bit tight! Valves are normally fully open by 1½ turns.

This picture shows one connector of a Drayton TRV4. Note the size of the round hole compared to the 15mm of the main body. You will see that inside the small round hole there is a rectangular opening. This is the built in balancing facility of the TRV4. This opening can be varied by using the appropriate tool. The picture shows the smallest opening and would be the setting for a 650W radiator. Using this method, the LSV is left fully open.

View media item 18380

 

[Tipper]

I assume you have a Vaillant boiler too. If so then there is another setting in the boiler that affects the speed of house warm up.

There is an anti-cycling timer which is factory set on mine to 20 minutes. As the house approaches the set temperature the heat required from the boiler reduces and so the boiler will probably cycle. If this setting is too long then the boiler is off more which allows the circulating water to cool too much and the house takes ages to get up to temperature.

You could try shortening this timer via the control settings menu on the boiler.

 

[arlester]

I assume you have a Vaillant boiler too. If so then there is another setting in the boiler that affects the speed of house warm up.

There is an anti-cycling timer which is factory set on mine to 20 minutes. As the house approaches the set temperature the heat required from the boiler reduces and so the boiler will probably cycle. If this setting is too long then the boiler is off more which allows the circulating water to cool too much and the house takes ages to get up to temperature.

You could try shortening this timer via the control settings menu on the boiler.

Sounds like you've litteraly described my situation. house takes forever to reach temp. on a EcoMax 630, how would I go about making the aforementioned adjustments?

 

[Tipper]

On my 937 combi you can set it via the control settings menu by pressing buttons on the electronic boiler control panel.

Have a look in the boiler manual which should be available online on the Vaillant website if you haven't got one.

BTW I tried changing the control characteristics/route adjustment but it seemed to make no difference.

If Vaillant would describe somewhere what all the available adjustments do it would make life easier! Any professionals have any additional documentaion from Vaillant they could share?

 

[arlester]

As for balancing the rads I had them professionally balanced at the same time as a powerflush. I observed all rads turned off, then one by one (first on run first) turned on and using clip on thermometers, adjusted flow and return until difference was 12degrees (I think, don't quote me).

12 degrees sounds about right, though modern condensing boilers are designed for a 20 degree differential.

Because of the interaction between radiators it is normal to have to go round several times before you get the balancing right.

It just didn't provide any heat through the bay rads x 3 and the rad furthest away. It was like the boiler would fire up, pull the hot water through the run of rads and just cut out before it managed to fulfill the awkward ones.

Sounds as if the balancer only went round once!

If I (just for arguments sake) turned the thermostat to 30, they would eventually get hot but only once the rest of the house was unbearable.

Thermostatic valves would help.

Interesting however what you say that anything less than circa 1/2 turn and they might as well be open fully.

1/2 turn is a bit tight! Valves are normally fully open by 1½ turns.

This picture shows one connector of a Drayton TRV4. Note the size of the round hole compared to the 15mm of the main body. You will see that inside the small round hole there is a rectangular opening. This is the built in balancing facility of the TRV4. This opening can be varied by using the appropriate tool. The picture shows the smallest opening and would be the setting for a 650W radiator. Using this method, the LSV is left fully open.

View media item 18380

Read all your various posts on bablancing and feel confused. wonderd if you could advise on the following as you've been so helpful before. My system heats up perfectly. Perfectly meaning that all the rads heat up at the same time although they do take along time as there the old school column rads style which I believe hold alot of water. My question is when I've measured the incoming and outgoing temps to balance the system using an infrared thermometer, the flow and return temps are almost the same all the way round despite the wheel being cranked down to 1/4 turn on some and fully open on others. As I said the system heats up evenly and all the rads get equally hot. Is there any negative effects to having an even flow and return temp in which case I can go round and turn them down or should I just leave them. if theres no negatives Id rather leave well alone. Ive read various postings about the need for flow and return at the boiler to be a certain difference other wise the boiler wont condense and will modulate blah blah. thanks in advance! bt the way I have a Vaillant Ecomax 630 on large system (17 old school style column rads).