ICF Slow Cooker

[AliG]

Hi @MarcelHoldinga

 

The first thing to eliminate is whether or not the heating is on by mistake.

 

In a well insulated house, if the temperature gets up to 23C and the thermostat is set at 18C, the heating would take days to come on unless it is very cold outside. Thus I would be surprised at your floors being warm. The coldest room in my house today is 19C and the heating hasn't been on there in weeks.

 

Thus although your flow temperature seems high, I doubt that is what is causing the issue., although it could still need adjusted.

 

I guess if the house cools down slowly, the floor would also, so it could be the flow, but the simplest start point is to make sure the heating is off and not pumping warm water through the UFH loops.

 

Edited November 11, 2020 by AliG

[SteamyTea]

3 minutes ago, AliG said:

Is off and not pumping warm air through the UFH loops.

Or water, even

[AliG]

Through the power of editing that never happened

[SteamyTea]

13 minutes ago, AliG said:

Through the power of editing that never happened

Yes, it is barmy putting a time limit on it, how do I now get all my posts deleted.

[ProDave]

1 hour ago, SteamyTea said:

Yes, it is barmy putting a time limit on it, how do I now get all my posts deleted.

It's an anti spam measure.  Spammers were joining the forum, making a very innocent looking post, then some time later editing the post to add their spam without being noticed.

 

[SteamyTea]

43 minutes ago, ProDave said:

Spammers were joining the forum, making a very innocent looking post, then some time later editing the post to add their spam without being noticed.

Yes, and often made more sense than some legitimate contributors, and less offensive.

[scottishjohn]

23 hours ago, joe90 said:

I concur with the above, MVHR will not move much heat. My heating (ground floor only) has not come on yet this year ( one zone = ground floor set to 21’ with a room stat in the hallway) so no water is being circulated in the UFH. The ASHP heats the DHW when it’s called for and ready to heat the house when the room stat calls fir heat.

If it did then the heat recovery is crap.LOL

and with the gaps under doors the whole house will got same temp with MVHR--drop thermostat or turn off loop to bedroom if you can  and see result

Edited November 11, 2020 by scottishjohn

[Temp]

Can't add much except.. check that the stats are controlling the right floor loops. We had two crossed over and took awhile to figure out what was going on because the stats were eventually being satisfied.

[AliG]

I had that, one room got to 27C before we figured out what the problem was.

[MarcelHoldinga]

7 hours ago, Stones said:

@MarcelHoldinga  Our house is ICF, ....

 

As suggested by others, reduce the set flow temp down.  If you are not convinced about reducing it in one go, do it in small steps, 2C every three or four days and see what the difference is.  If you have the option of weather compensation control, you could try that instead.  

 

Our slab is around 130 sqm (about 120sqm internal), so not too far off yours....
I've had a root through the menus on our ASHP (Daikin Altherma), and it looks like the installer has stopped down the menus so we're not able to select weather compensation  - it's there in the manual, but the footnote indicates that some options may be hidden from view... ?

Frustrating that I don't appear to be allowed to control my own heating system in my own house... coudl it be to do with the fact we're getting RHI? Do they stipulate specific usage conditions on the units being installed?

[MarcelHoldinga]

7 hours ago, Bitpipe said:

 

Sorry, we can be very quick to jump in with questions and answers and sometimes forget to say hello!

 

That's quite alright - it shows you're eager to help!

 

I've found the replies so far very useful.

 

[MarcelHoldinga]

3 hours ago, Temp said:

Can't add much except.. check that the stats are controlling the right floor loops. We had two crossed over and took awhile to figure out what was going on because the stats were eventually being satisfied.

 

Cheers, Temp.

I'll have a look at the weekend - my home life is still disrupted by work these days.
 

[MarcelHoldinga]

9 hours ago, joe90 said:

with my ASHP system the hot water from the heating buffer tank is set to 35’ but at the manifold it’s blended down to 24’, this stops heating over shooting ,  does yours have a blending valve?

Not sure it does - it does have separate controls for LWT (UFH) and DHW; UFH was set to 38 (reducing that slowly) and DHW is currently set at 45, with a sanitising run once a week to keep legionella at bay.
It appears the unit was set up with just the basic settings available to us LWT temp up and down, no weather compensation or any of the fancy modes that Stones mentioned in his post...

[joe90]

@MarcelHoldinga so you have no blending valve on your manifold?

[MarcelHoldinga]

22 minutes ago, joe90 said:

@MarcelHoldinga so you have no blending valve on your manifold?

Not aware that I do - would it be obvious from looking at the various pipes/manifold?

[joe90]

12 minutes ago, MarcelHoldinga said:

Not aware that I do - would it be obvious from looking at the various pipes/manifold?

Any chance of a pic?

[MarcelHoldinga]

13 hours ago, joe90 said:

Any chance of a pic?

This is our setup, internal ASHP is on the left, DHW tank on the right.

I know the left hand black unit on the pipes diverts water either to the UFH od DHW, with the one attached to the manifold being the UFH circulation pump, but other than that, can you tell I'm fully clued up? ?

[PeterW]

No blending valve - ASHP is straight into the manifold and there is a bypass on the end of the  manifold rails. 
 

Does the ASHP have multiple temperature settings..? And can you get a picture of the black box valve and any model number off it ..??

[SteamyTea]

Lack of pipe insulation as well.

[joe90]

Yes as said above no blending valve so the temp of the ASHP water goes into the floor, you did say you could reduce the heating temp so I think this is the way to go.

[PeterW]

Overshoot may be because that is a mid position valve and not a full diverter valve. If the DHW is coming on at the same time as the heating it could be dumping 50c water into the manifold and there are no safety mechanisms on those setups. For the sake of a £50 TMV I cannot see why installers don’t fit them. 

[ProDave]

Regardless of the issues noted above, each pipe loop (bar one, what is the left hand loop going to?) have an actuator controlled by a room thermostat.

 

So when each room reaches it's set temperature the flow of water to that room will stop.  So the overshoot you are seeing can only be water temperature too hot and too much energy in the slab continuing to warm the room after the water has stopped flowing.

 

Turn the water temperature down quite a lot and see how things improve.

 

Another observation.  All the flow meters on loops with actuators are showing no flow.  So the room thermostats have turned off and the water has stopped flowing.  BUT that left hand loop without an actuator is still flowing at a high rate.

 

So water is still flowing somewhere into the slab.

 

What is that left hand loop for and where does it go?

 

Normally the control box above the manifold would turn off the "call for heat" when all the room thermostats are satisfied, stop the pump, and stop calling for heat from the ASHP.  But in your case in spite of all the room stats satisfied, the pump is still running pumping around that left hand loop and presumably still being heated by the ASHP.  Some attention to the control scheme is required I think.

 

Agree with Peter. you do NOT want a mid position valve.  That should be a 2 position valve so it never does heating at the same time as DHW

[dpmiller]

Looks like an ESBE valve actuator but there are quite a number of types...

[AliG]

47 minutes ago, SteamyTea said:

Lack of pipe insulation as well.

 

Weird that it is so neatly fitted yet no insulation. There will be a lot of heat coming off the cupboard which in itself will be boosting temperatures in the house.

 

Not sure what the reason for having a loop without an actuator is. Is the system calling for heat to this loop even though all the thermostats are off?

 

 

[MarcelHoldinga]

49 minutes ago, PeterW said:

No blending valve - ASHP is straight into the manifold and there is a bypass on the end of the  manifold rails. 
 

Does the ASHP have multiple temperature settings..? And can you get a picture of the black box valve and any model number off it ..??

ASHP has got temperature setting - nothing fancy, just a simple, single temperature - it looks like any advanced methods of controlling UFH temp have been switched off by the installer

 

Images of diverter valve (red line, on the left), UFH circulation pump (middle) and actuator valves on manifold (right).

The loop on the left (blue cap) is an open loop to the main bathroom - if there's a bypass, I'm not enirely sure why this would be there. The installer said that your bathroom is usually the hottest room in the house, and that there would normally always be an open loop into there...

I've got a pic of all the destinations on the manifold pipes somewhere, but I'd need to have a look for that and post that later, 'cos I'm at work at the moment...