manifold hot but heating off

[lizzie]

Hello all hope the enforced Christmas break was enjoyed. Here is a little holiday puzzle.

 

Our ufh is a b mystery to me even with the hours spent on u tube etc.

 

We are getting a big blast of heat in the house around 10pm every day its very noticable.  Our house temp seems to rise overnight without heat kicking in.  MVHR/UFH installed by same person....the one who has not been back to finish the job........I turned the UFH right down on thermostats so its not kicking in at all for last 24 hours or so yet the living area manifold in the plant room is hot and I can feel water running in the pipes, the actuators are not up.  The second manifold for bedrooms is located in a cupboard in my bedroom and that is stone cold.  All the thermostats are set the same throughout the house so its not that.

 

Anyone point me at a straighforward answer? Failing that I am going to have to try and find someone to come and sort this out. Anyone know any experienced UFH/mvhr people in the Midlands, I run UFh on mains gas boiler.

 

Thanks in anticipation.

[PeterW]

Sounds like the circulation  pump has been fitted to run when the boiler runs which would be the same time as when you have hot water etc.

 

Isn’t it a Robbens UFH system ..? Pretty sure they have a pump trigger off the main UFH board but wouldn’t know without the exact model. 

 

Have you got a schematic you can post ..?

 

And the midlands isn’t far from South Wales ... ?

[lizzie]

2 hours ago, PeterW said:

Sounds like the circulation  pump has been fitted to run when the boiler runs which would be the same time as when you have hot water etc.

 

Isn’t it a Robbens UFH system ..? Pretty sure they have a pump trigger off the main UFH board but wouldn’t know without the exact model. 

 

Have you got a schematic you can post ..?

 

And the midlands isn’t far from South Wales ... ?

Thank you....yes not far......he he...It is a Robbens system

 

Is the attached the schematic?  I have a book of how to install/commission plus these loose pages.  Some weeks ago I did do a little drawing myself of which actuator corresponds to which zone....in a box in the garage will need to find. The detail on the quote is also attached.

 

My gas bills are higher than I would have anticipated - maybe this is the reason.

 

We have not been able to get the house at a comfortable living point yet its either too hot or too cold.

 

 

ufh.pdf

ufh robbens quote detail.pdf

 

Edited December 27, 2018 by lizzie

[ProDave]

14 minutes ago, lizzie said:

We have not been able to get the house at a comfortable living point yet its either too hot or too cold.

 

That is a usual symptom of getting the themostats and actuators mixed up, e,g living room thermostat controlling snug zone.  One of them will overheat and the other will go cold.

[Nickfromwales]

5 hours ago, ProDave said:

That is a usual symptom of getting the themostats and actuators mixed up, e,g living room thermostat controlling snug zone.  One of them will overheat and the other will go cold.

And the symptom of crap room stat with huge hysteresis giving over and under shoot of the stat set point. 

[ProDave]

2 minutes ago, Nickfromwales said:

And the symptom of crap room stat with huge hysteresis giving over and under shoot of the stat set point. 

cr@p wiring usually.  Even the humble mechanical thermostat has a very low hysteresis if wired properly. But forget the neutral (nah don't need that) and it's a different story.

[Nickfromwales]

1 hour ago, ProDave said:

cr@p wiring usually.  Even the humble mechanical thermostat has a very low hysteresis if wired properly. But forget the neutral (nah don't need that) and it's a different story.

Not really good enough for PH or UFH afaic. Wiring doesn't affect the hysteresis, it just makes it work   

[ProDave]

2 minutes ago, Nickfromwales said:

Not really good enough for PH or UFH afaic. Wiring doesn't affect the hysteresis, it just makes it work   

It does.

 

A mechanical thermostat has an "accelerator" heater wired between the Sw L out and N. It's purpose is to slightly warm the local environment to overcome the hysteresis of the mechanical thermostat.

 

A lot of people just connect the L in and Sw L out and ignore the neutral = no accelerator heater and huge hysteresis.

 

Mine are working just fine.

[Nickfromwales]

I don't usually bother as they have an adverse affect in the winter. Their the crudest of stats and I haven't fitted one for prob over a decade, other than in rentals where the Tennant only understands noises.

 

[lizzie]

I am totally lost?

[Sue B]

The only thing I can contribute is remembering the confusion over our controls last time round. We had laid the UFH ourselves, run the cat 5 (e) cabling to each room control and wired it up myself (OH who did the rest of the first fix said he knew nothing about cat 5 cable so I had to do it). Wired up the control box in the garage, reading manuals endlessly to make sure it all worked fine.

it all seemed ok but I couldn’t work out why it was on at certain times.  I was used to an old fashioned timer, on off, on off with a very up to the moment 5 and 2 day rotation - state of the art stuff!!  

 

I missed the vital piece piece of information that the new room controls were not on off on off but simply room temperature targets for 4 separate times during the day.  It took two weeks of scratching head to realise that

my confusion over the control wanting a temperature at point 4 (which I thought was turning it off) became clear.  The manual was clear, I was just being dense!

[Sue B]

8 hours ago, ProDave said:

That is a usual symptom of getting the themostats and actuators mixed up, e,g living room thermostat controlling snug zone.  One of them will overheat and the other will go cold.

And yes - I had done that too.  I had to wait for a cold day, turn all the rooms off and turn the problem one on and wait.  It took over a day to prove but only a few minutes to correct once I knew what I’d done.

[lizzie]

Thanks all...think I have the answers now but how to remedy final step is still something I have to find.... this is where I am at and hoping I have it right!

 

@Sue B yes have the 5/2 four times a day  - all was set up to go on and off as should be and  @ProDave I hope all my actuators and zones are correctly logged and working now after testing same thank you.

 

There appears to have been a 'hidden' issue with the hot water..... we have a separate timer for HW it is still part of the Heatmiser system but is a dedicated HW timer.  It was set for 7.30 -9am 7 days a week - thats all just on once a day.  When I look on the app it just shows that once a day cycle, water always scalding hot, we never ever run out of very hot water and our plant room is always extremely hot.  Much head scratching as to why boiler still coming on with everything else off and finally I found it.  The HW programme on the app was overriding the timer behind the scenes and water was coming on four times a day on the 5/2 pre sets.  Now sorted that so boiler only coming on when heating on and/or hot water.  Manifold is getting hot when HW heating only is on so  I think @PeterW has hit on the reason - a circulation pump setting.  If anyone could point me at how to reset that I think I am almost there...except for those bits that have still not been fitted on manifolds LOL

 

Thank you superstars - has kept me busy over Christmas!