ASHP/ buffer tank issue

[ReedRichards]

1 hour ago, Rupe30 said:

Lukewarm blended water is absolutely what we get. Even set to 55 degrees it doesn't feel close to that. 

 

 

55 degrees is scalding hot, you would get third degree burns in 10 seconds.  Do you perhaps have a blending valve on the outlet from your hot water cylinder?

[markocosic]

I don't have UFH / a house decent enough to be comfortably heated by UFH as yet. 😉

 

 

Cambridge house is a piece of junk. Might as well be insulated using a colander. Radiators running TRVs not in use at the moment as heating via the A2A heat pump / AC as cheaper.

 

 

Vilnius apartment is nice. Radiators running weather compensated district heat via TRVs and an A2A heat pump / AC though. 

 

 

Cabin build will be close; but wall/ceiling heating rather than underfloor heating as (1) we didn't scope-creep it in soon enough not to mess with finished floor heights; (2) we'll be having a pine floor that isn't amazing for heat transfer and she would only go cover it all with rugs anyway; (3) it's more suitable for summer cooling (ground source heat pump setup so can dump heat into the ground loop) than a cold floor as higher up and less damaged by potential condensation.

 

That'll run as a single main zone (open plan space); with either return temperature limiters for the bathroom and the bedrooms or indeed a large TRV as an air stat to provide for consumer-facing balancing. 

 

This kind of thing:

https://www.variotherm.com/en/products/modular-wall-heatingcooling.html

 

But using the two small aubergines and a large bottle of vodka method.

 

- insulation to the horizontally battened service cavity

- 70 or 100 mm strips of plasterboard running vertically as spacers

- 12 or 16 mm UFH pipework stuffed in the gaps

- Plasterboard / tile adhesive to hold them in

- Another piece of plasterboard as the finish layer / spreader layer

 

A cross between these two methods if you will:

 

 

 

[markocosic]

1 hour ago, Rupe30 said:

I was going to ask if that was a better way of doing it. 

 

Enough to cause a problem or worth a go?

 

Worth trying. Easy enough to revert.

 

 

1 hour ago, Rupe30 said:

I'll measure up tomorrow I think we do have that height. Is it worth having a smaller buffer than losing it all together?

 

Let's answer that after you've decided whether or not you can do without all those valves that can randomly turn off so may zones that the heat pump has nowhere to put it's heat.

 

They've put that in there so that the heat pump has something to do if all the zones shut down. The lady of the house wanting to run one towel rail and one bathroom floor even when it's 25C outside may dictate that you keep it.

 

There's room for two vertical tanks up there though if you don't vomit equipment in like your average plumber.

 

[Rupe30]

On 08/03/2023 at 22:41, markocosic said:

 

Worth trying. Easy enough to revert.

 

 

 

Let's answer that after you've decided whether or not you can do without all those valves that can randomly turn off so may zones that the heat pump has nowhere to put it's heat.

 

They've put that in there so that the heat pump has something to do if all the zones shut down. The lady of the house wanting to run one towel rail and one bathroom floor even when it's 25C outside may dictate that you keep it.

 

There's room for two vertical tanks up there though if you don't vomit equipment in like your average plumber.

 

 

 

Sorry to go radio silent, ASHP problems melt away in summer!

 

After the last post I set all thermostats to 30 degrees to stop them clicking on and off and adjusted the flow rates to all the zones on both manifolds till the rooms held temperature. It was challenging to balance the system, downstairs all zones are on minimum flow and manifold pump is on minimum setting and the lounge still got too hot so I had to use the thermostat for that, but I used it as a timer rather than temp target to avoid it clicking on and off repeatedly. Upstairs 2 rooms require  max flow with the manifold pump on max setting to keep temperature which is what is restricting the whole system as the rest of the house is pretty much on minimum flow rate.

 

Th So In summary yes I can run the whole house on, but I need to turn two small bedrooms off and the lounge sometimes . Running the AI mode at -2 so I think all in all it's working well considering house is a comfortable 21 degrees which much warmer than we had it previously.

 

One issue of running The system in this way is that I can only adjust the temperature of the house using the LG controller using the + or - on the AI mode and it takes a long time to take effect. Which means I can't have the house cooler at night. 

 

I'd like to track my COP to as i figure that's a good way to track the efficiency. I can't see any heat output data on the LG controller so am I going to have to fit my own heat meter and electric meter to determine COP or is there an easier way?

 

Figured out the issue with the hot water, cylinder was installed back to front, so the hot feed was attached to the cold (which has a dip pipe to the bottom of the tank) and the cold feed was entering into the top of the tank. Much better since we've re-plumbed.

[markocosic]

24 minutes ago, Rupe30 said:

 

Figured out the issue with the hot water, cylinder was installed back to front, so the hot feed was attached to the cold (which has a dip pipe to the bottom of the tank) and the cold feed was entering into the top of the tank. Much better since we've re-plumbed.

 

That's the sort of thing I'd do 😂 - good it's an easy fix!

[ReedRichards]

23 hours ago, Rupe30 said:

Running the AI mode at -2 so I think all in all it's working well considering house is a comfortable 21 degrees which much warmer than we had it previously.

If your AI mode is anything other than zero (and this is not just a temporary adjustment) it means that your Weather Compensation temperature settings are slightly wrong.   In your case the Leaving Water Temperature must be set 2 degrees too high so you should reduce your WC temperature settings for the LWT by 2 degrees then set AI=0.  It's not critical to do this but it restores the full range of adjustments you can make, down or up.  However I'm really glad you have the comfortable warmth you were seeking.

 

23 hours ago, Rupe30 said:

One issue of running The system in this way is that I can only adjust the temperature of the house using the LG controller using the + or - on the AI mode and it takes a long time to take effect. Which means I can't have the house cooler at night

 

I've never found any indication that the LG controller can program the AI setting, which is the only way to do a night-time setback unless you use Air + Water on the controller and can program a target temperature for the room the controller resides in (I can't remember the details of your set-up).

 

On 14/09/2023 at 11:41, Rupe30 said:

I'd like to track my COP to as i figure that's a good way to track the efficiency. I can't see any heat output data on the LG controller so am I going to have to fit my own heat meter and electric meter to determine COP or is there an easier way?

 I don't think there is an easier way.  If the LG Therma V heat pump does record any heat output data, this is not made available via the controller.

 

On 14/09/2023 at 11:41, Rupe30 said:

Figured out the issue with the hot water, cylinder was installed back to front, so the hot feed was attached to the cold (which has a dip pipe to the bottom of the tank) and the cold feed was entering into the top of the tank. Much better since we've re-plumbed.

That's a bit terrible.  I can't believe even the least competent plumber would make a mistake like that.   

[Rupe30]

Thanks for your response @ReedRichards 

The only thing I need to figure out now is whether I can reduce my 180l buffer vessel (and whether the savings would be worth it Vs the cost to change). If anyone could chime in on that subject it'd be appreciated.