What does this +5 do to water law, Samsung ashp

[Andehh]

, I have increased my Samsung water law by +5 degrees to see what it does.... But it's difficult to tell?

 

Can anyone advise in layman's terms please?

 

Thanks

Edited yesterday at 21:14 by Andehh

[PhilT]

If your Water Law (WC) with no adjustment was, for example, set as:-

Outside 15>>>>>>>>>>>>>>>>> -2 deg C

Flow      35>>>>>>>>>>>>>>>>>50 deg C

 

your adjustment of +5 to the flow temp takes effect across the whole range, so the Water Law becomes:-

 

Outside 15>>>>>>>>>>>>>>>>> -2 deg C

Flow      40>>>>>>>>>>>>>>>>>55 deg C

 

so either you should be feeling a lot warmer, or your room stat cuts the heating sooner, or both.

[Andehh]

Thanks very much!

 

mine looks to be:

 

Outdoor temp got water law:

15 degrees ........3.0

 

Water out temp for WL1 Heat (WL1 floor)

36 degrees..... 43degrees high target

 

Water temp out for WL2 Heat (wl2-fcu)

36 degs....... 43 degrees

 

However even boosting it by the 5 degrees as you suggested, after 3.5 hours of running my UFH temp is still only 29.2 degrees it is - 3.5 degrees outside.

 

 

We have a very well Insulated property, but a few of the rooms have a small floor area but have high ceilings/Mezzanines. This means they do struggle to get warm when it gets very cold.... Just too little surface area.

 

 

With the octopuses cosy tariffs I'm less worried at efficiency, vs hammering the electricity when it's only 11p during the cheap rates.

 

 

Is there a reason I'm not seeing the 29degree water outlet temp getting to something warmer to really force the heat into these rooms? Was hoping the +5degrees would do this!

 

 

[Andehh]

For what it's worth we are fairly lightly zoned, basically children's bedrooms vs master room and bathrooms vs living areas....again to try and force as much heat as possible into the small but tall children bedrooms. Morning and afternoon cosy everything is on until thermostats hit 22 degree limits (rare in this cold level temps), but the 10 to 12 is only children's bedroom is give them the extra helping hand.

[JamesPa]

2 hours ago, Andehh said:

For what it's worth we are fairly lightly zoned, basically children's bedrooms vs master room and bathrooms vs living areas....again to try and force as much heat as possible into the small but tall children bedrooms. Morning and afternoon cosy everything is on until thermostats hit 22 degree limits (rare in this cold level temps), but the 10 to 12 is only children's bedroom is give them the extra helping hand.

Have you hit the max output of the heat pump?

[sharpener]

1 hour ago, JamesPa said:

Have you hit the max output of the heat pump?

 

My first thought. But it might be better to increase the slope of the WC (Water Law) instead of adding an offset - if that's what the +5 deg setting is, I am not too familiar with Samsung terminology. If in doubt RTM.

[Andehh]

Max output being my slab size, and for how cold it is from exiting a heat off period of 4-5 hours, meaning even with ashp at full chat for 'only' a few hours of octopus cosy period it can't get the flow temp up any higher then 30 degrees?

 

Therefore the 5 deg increase is meaningless, ie.. Increasing top speed of a car stuck in traffic?

[PhilT]

I have Cosy but in these cold temps I'm running mine 24 hours a day at a very steady 20 room temp. I still get 8 hours at half price. The extra cost of the 3 hours 4pm to 7pm is partly offset by the better efficiency of constant running and the comfort of constant warmth and not having to worry or fiddle about with the controls and timer

Edited 11 hours ago by PhilT

[JoeBano]

Have you got a low tariff function on your heat pump? I’ve got one on mine (grant aerona3) i use between 12-3pm normally cheapest time on octopus agile to boost the flow temperatures +3c to avoid the expensive 4-7 period for me. 

[sharpener]

6 hours ago, Andehh said:

Thanks very much!

 

mine looks to be:

 

Outdoor temp got water law:

15 degrees ........3.0

Water out temp for WL1 Heat (WL1 floor)

36 degrees..... 43degrees high target

 

Water temp out for WL2 Heat (wl2-fcu)

36 degs....... 43 degrees

 

However even boosting it by the 5 degrees as you suggested, after 3.5 hours of running my UFH temp is still only 29.2 degrees it is - 3.5 degrees outside.

 

That is only 7 degrees change for 12 deg change in OAT so a slope of 0.6, maybe you should up it a bit.

 

The time constants involved in UFH are so long that you cannot realistically expect an immediate response after an off period. If your HP size was well matched to the heat loss then it would need to run nearly the entire time in cold weather.

 

6 hours ago, Andehh said:

it is - 3.5 degrees outside

 

That seems very cold for Northamption even in the recent cold snap.

 

6 hours ago, Andehh said:

 

Is there a reason I'm not seeing the 29degree water outlet temp getting to something warmer to really force the heat into these rooms? Was hoping the +5degrees would do this!

 

 

Either your WC settings are still wrong or you should not be trying to run the HP intermittently or it is simply not big enough.

 

What does your installer's Heat Loss Calculation say and how does yr HP capacity compare with this?

 

Edited 9 hours ago by sharpener

[JohnMo]

6 hours ago, Andehh said:

3.5 hours of running my UFH temp is still only 29.2 degrees

That sounds about correct and is exactly what I see if I let the floor get too cold. Your heat pump controls dT first and slowly working up to target flow temp. So if the floor is cold your return temp by default is also cool. 

 

Last year I did an experiment set target flow to 35, never got above 32, after nearly 12 hrs of running. Your floor is a huge mass to heat, they have massive inertia.

 

Simple answer is it isn't a gas boiler, you need to run it almost constantly in cold weather. Add to this you will be defrosting on a regular basis, which fights against short running regime.

[PhilT]

7 hours ago, Andehh said:

but the 10 to 12 is only children's bedroom is give them the extra helping hand.

Could you please clarify what this is saying exactly?

[sharpener]

I took it to mean the Octopus Cosy cheap period 2200 - 2359.

 

Like you and me the OP is on Cosy.

[PhilT]

41 minutes ago, sharpener said:

I took it to mean the Octopus Cosy cheap period 2200 - 2359.

 

Like you and me the OP is on Cosy.

Ah yes of course. I must admit I was doing a lot of this until the temps dropped below zero then I gave up. Especially when I saw the power spikes after several hours off, even with adaptive, which is a lot gentler than straight WC