Not warm enough! Is it wind?

Netexporter

My 5kW Samsung is keeping my house perfectly warm at just under 30 degrees flow temperature, with radiators (15 hour power cuts notwithstanding).

michaels

Could the heat pump have been running the hot water programme when the pic was taken?

valiant24

matelodave said:

As @Reed_Richards suggests, 56.4 degrees is excessively high for a heat pump, even with radiators . Underfloor heating would generally be around 40-45max.

In fact be careful that, as most heatpumps max out at 50-55 degrees, that you dont have an auxiliary immersion boost heater switched in as well - it used to be a big complaint with EcoDan heatpumps that they were set too high and the aux heater was coming on.

At five degrees outside, ours would be about 33-35 increasing to 40 at -5 outside. Most of the time its nearer 30 degrees.

You really do need to understand how your system is set up and how all your controls are set (both the heatpump controller and the heatmiser controls) have you got zones and timers set.

Generally an underfloor system works like a storage heater at a continuous gentle low heat rather than being blasted for a couple of hours twice a day. More controls can end up making the system less stable and very expensive to run especially if its being run like a gas or oil boiler.

Have a shufti here for how to tweak weather compensation on the Samsung controller and suggestions for temperature settings for u/f heating - 
https://www.bing.com/videos/riverview/relatedvideo?q=Samsung+AE120RXYDEG&mid=0B9B617AD841EC3A5B510B9B617AD841EC3A5B51&FORM=VIRE

Having a look at this video and the piccy of your controller showing 5 degrees, it looks like someone has also cranked up your temp to 5 degrees above its normal setting - https://www.youtube.com/watch?v=kqfbvjb-ZTY&list=PLa_cY4oQlxWtQcP8WLJ1KuZQZ41wDqV67&index=7 so has some random fiddling been done?

As a rule of thumb, every degree above nominal on a heat pump will increase its energy consumption by around 2.5% where nominal is 35 degrees. So running yours at 56 could be increasing your energy consumption by nearly 50%. Not sure if that's the same with a high temperature unit but heatpumps are most efficient when running at the lowest possible temperature, even if that means running them for longer.

Thanks.
Currently Water Outlet is 38.7C and Indoor 22.9C.
I'd like to know what these were before the power cut.  Not sure why we have "weather compensation" on, having watched the vid you linked.   It's generally quite mild where I live (SW England).

Reed_Richards

If I were you I would turn off "Water Law" (weather compensation), set the leaving water temperature to 40 C and see if that keeps you warm enough.  If it does you will be running your heat pump much more economically.  After that you can take more time to sort out exactly what settings you need.

valiant24

Reed_Richards said:

If I were you I would turn off "Water Law" (weather compensation), set the leaving water temperature to 40 C and see if that keeps you warm enough.  If it does you will be running your heat pump much more economically.  After that you can take more time to sort out exactly what settings you need.

After watching the linked vids I did disable Water Law; set the outdoor Low and High Temp to 14C and -3C respectively;  and the Low and High Target Values for Water Out Temp at 30C and 45C respectively.

These seemed to be the recommendations for a well-insulated house with under-floor heating only.

What should I be looking for to see the effect, if anything, beyond a house keeping up to temperature better?

Many thanks everyone, btw!

Reed_Richards

The main effect would be that you use less electricity because you're not asking your heat pump to make the water hotter than it needs to.  But if you disabled Water Law then outdoor and water out temperatures are of no relevance, you should now be operating at a constant water out temperature, irrespective of the outdoor temperature.  And you should be able to set what that water out temperature is, although I myself don't know how for your make of heat pump.

Netexporter

For Samsung you select engineering menu (cogwheel symbol) and use the code 0202 to get in.

valiant24

Netexporter said:

For Samsung you select engineering menu (cogwheel symbol) and use the code 0202 to get in.

Thanks.  I was asking though what settings I should set, rather than how to do it.

valiant24

An update:

Everything's very toasty now!

Trouble is, a few things changed: the high winds have died down; I shut a draught vent that shouldn't have been open; and I removed Samsung's "Water Law".   And I don't know which fixed the issue!

Reed_Richards

That's great, but with the correct settings then Water Law should save you money.  So if you can manage to set it up correctly (and it wasn't correct before) then that would be worthwhile.