Hot water cold after weekend away

[markmanningnz]

Hi all, new to this forum and looking for a bit of advice please.

Have been noticing recently some odd behaviour with our hot water system. If we go away for the weekend, leave Friday afternoon and back Sunday night, the hotwater is lukewarm at best up our return Sunday evening. I then need to boost the HW for an hour to get the water nice and hot again.

I have Tado smart controls installed and have triple checked there is no "home/away" geofencing triggering the the HW to turn off so the normal schedule (off/on for an hour in AM and PM each day) is still set and working while we're away. Also, the rads were working just fine when we got home last night so it's as if no HW use over the weekend seems to trigger this condition.

Boiler is Bosch Greenstar 4000 system boiler fitted last year. Hotwater cylinder approx 18 years old. Any insights or advice would be greatly appreciated!

Mark

 

[Ben-gee]

Is it an unvented cylinder or a gravity fed vented one?

 

[markmanningnz]

Is it an unvented cylinder or a gravity fed vented one?

Unvented system mate. S plan system from what I know.

 

[Ben-gee]

Has there been any water going through the tundish and dripping from the discharge pipe?

 

[markmanningnz]

Has there been any water going through the tundish and dripping from the discharge pipe?

Thanks for your reply. No, no dripping that I've seen. When we are here throughout the week, the system is fine and we have no problems with hot water so it is very odd...

 

[JohnBS]

Do any of your hot-water pipes run under the ground floor?
Think about how the hot-water system 'knows' you're away: do you switch off the central heating?

 

[markmanningnz]

Do any of your hot-water pipes run under the ground floor?
Think about how the hot-water system 'knows' you're away: do you switch off the central heating?

Thanks John. No pipes running under the ground floor. Central heating is not switched off when we go away for the weekend, and the house was warm from the CH operating when we got home - just the HW that was lukewarm/bordering on cold. This is what I cant figure out - I wonder if the Tado system is showing "home/away" (geofencing) as being disabled, but its actually not (at the backend somewhere) and this might be what is causing the HW to turn off.... otherwise I'm at a complete loss!

 

[Ben-gee]

Does your cat know how to operate the shower?

 

[markmanningnz]

Haha. Yeah, could be - at this stage I'm open to any suggestion! Going to get onto Tado support and see if they can check the back end - I reckon its gotta be a rogue home/away setting.

 

[JohnBS]

the Tado system

I'm not familiar with the Tado system, but if it incorporates some logic such as
If [no hot water demand for 24 hours], Then [switch off water heating], it could be an "undocumented feature" . Has it happened more than once, i.e consistent pattern?

 

[snowhead]

Just Google this and found someone had the opposite problem.
Tado set to away mode, but Hot water still coming on while they were away.

The suggested problem was that Geolocation was set Off in the water time blocks? but should be On in all time blocks.
I don't have Tado, but is this issue the opposite, Geofencing is On in one or more of the time blocks in the weekend period, not just in the On time block?

 

[markmanningnz]

Thanks John. Yeah, has happened before, and this weekend just gone was the 3rd time it's occurred. I think you're onto something regarding a Tado "undocumented feature" - I think they have a few of them....Will investigate this angle further.

 

[markmanningnz]

Just Google this and found someone had the opposite problem.
Tado set to away mode, but Hot water still coming on while they were away.

The suggested problem was that Geolocation was set Off in the water time blocks? but should be On in all time blocks.
I don't have Tado, but is this issue the opposite, Geofencing is On in one or more of the time blocks in the weekend period, not just in the On time block?

Thanks...Will look into this at the same time!

 

[Ben-gee]

As an experiment could you go away for weekend but leave your phone at home- this would give the lack of use of system but retain geofencing.
I realise this is a big ask these days !