Best setting for Vaillant ecoTEC plus 637?

[Kate1]

We have Vaillant ecoTEC plus 637 + Vaillant uniSTOR VIH GB 250/3 BES 245ltr cylinder

What’s the best time programme settings for the DHW circuit & Circulation? Should I have them on constantly or certain time of the day say 6:00-8:00 to reduce energy bills? DHW circuit and circulation should use the same time programme right?

Thanks!

 

[CBW]

I wouldn’t suggest leaving them on constantly. I would work out, by trial and error, your hot water usage and requirements. I did mine (different boiler and cylinder to yours) to how long hot water is needed at certain times of the day, and how long it would last. I have it coming on 3 times a day. 45 min for before we get up, an hour in the afternoon to top it up, then again in the evening, the latter being the longest on period. If you have Vaillant controls, it might be capable of learning when you need it - @ScottishGasMan might be able to confirm this, or advise differently to my suggestion.

 

[Kate1]

That’s very helpful, thanks very much CBW. There is a separate time programme for Circulation (connected to the cylinder pump I guess), should I leave Circulation on all day say 6:00-22:00, or should it just come on when hot water is on? Thanks!

 

[CBW]

Not something I’m familiar with I’m afraid, but who I linked to before will know the answer to that, and he’ll be notified of it too.

 

[Harry Bloomfield]

That’s very helpful, thanks very much CBW. There is a separate time programme for Circulation (connected to the cylinder pump I guess), should I leave Circulation on all day say 6:00-22:00, or should it just come on when hot water is on? Thanks!

There is no point in circulating the water, until you are likely to need it, nor any point in circulating when you will not need it. Aside from the wasteful electric consumption, there will be heat loss from the circulation pipework too.

One way to some do it, is to have the circulation pump run when triggered by a PIR, located close to points of use of HW, like the bathroom and kitchen. That way it only runs, when such rooms are occupied.

 

[ScottishGasMan]

Firstly what controls are you using?

And do you have a DHW recirculation (bronze) pump? some of the controls will give you circulation timing option regardless of whether there is actually a hot water return circulator fitted. (Its far more common to not have one than it is to have one)

 

[Kate1]

Thanks, the control I’m using is Vaillant thermostat VCR700 which is mounted on the wall. There’re 3 options to set up time programmes: heating, DHW Circuit & Circulation. Circulation is connected to the pump. I can’t see any controls on the Vaillant cylinder or the pump, the pump looks like “GRUNDFOS UPS 15-50N TRADITIONAL SECONDARY HOT WATER CIRCULATOR 230V”, should I keep the pump on all day? When it’s off, I have to wait for a long time for the hot water to reach bathroom… thanks!

 

[ScottishGasMan]

Secondary circulation pumps are extremely wasteful in general, so definitely don't keep it on all day. If you have a regular work schedule then have it on when you're likely to use the bathroom, i.e. an hour or so in the morning and a few hours at night during the time you might use that bathroom.

Its not uncommon for the circulator to be controlled by PIR sensors, so it only runs when your in a room with a hot outlet, although this does require a reasonable bit of wiring which is not always easy to retro fit.

 

[Harry Bloomfield]

Thanks, the control I’m using is Vaillant thermostat VCR700 which is mounted on the wall. There’re 3 options to set up time programmes: heating, DHW Circuit & Circulation. Circulation is connected to the pump. I can’t see any controls on the Vaillant cylinder or the pump, the pump looks like “GRUNDFOS UPS 15-50N TRADITIONAL SECONDARY HOT WATER CIRCULATOR 230V”, should I keep the pump on all day? When it’s off, I have to wait for a long time for the hot water to reach bathroom… thanks!

I covered all that, in post #5 above, but another option would be to manually switch the pump on/off when you anticipate needing HW - maybe use one of those switches which automatically switch off, a few minutes after being triggered.

 

[Kate1]

Thanks, where can I find the switch which automatically switch off a few minutes after being triggered? I can’t seem to find this option from the control… The bathroom pipe is making vibration noise when the pump is on when we’re not using hot water, is it normal? Thanks!

 

[Harry Bloomfield]

Thanks, where can I find the switch which automatically switch off a few minutes after being triggered? I can’t seem to find this option from the control… The bathroom pipe is making vibration noise when the pump is on when we’re not using hot water, is it normal? Thanks!

Eric will have a better idea, but you can buy a cheap pneumatic push button switch, with adjustable run time. They are intended for use for stair lighting, in HMO's. You push the button in, pump comes on, and runs until the button gradually pops back out and switches off. A tiny brass screw inside, sets the run time. They are not very precise, but precision is not needed for this appliction.

 

[Kate1]

Secondary circulation pumps are extremely wasteful in general, so definitely don't keep it on all day. If you have a regular work schedule then have it on when you're likely to use the bathroom, i.e. an hour or so in the morning and a few hours at night during the time you might use that bathroom.

Its not uncommon for the circulator to be controlled by PIR sensors, so it only runs when your in a room with a hot outlet, although this does require a reasonable bit of wiring which is not always easy to retro fit.

Thanks! Do I need to match hot water schedule with the pump? Can I run pump schedule alone in the evening just when we need water? Thanks!