Heat Pumps - post here.

graememk

https://www.boards.ie/discussion/comment/121493184#Comment_121493184

I suppose with the controller and that thermostat in there is constantly calling for heat, that's why the circulation pumps are running constantly. Not necessarily a bad thing though. Heatpump is kicking in when the flow temperatures are dropping low enough, and boosts the temperature back up.

You do have a power monitor in home assistant though, I wonder could you add one for the heatpump too? Then at least you can separate the house use from the heatpump (eg overnight I can see a big jump in the house load and then also the HP coming in and out)

You could estimate house "idle" use by counting base power, and guesstimate the HP use.

Hp is running 4x in 30 mins. At about 1500w say 15 mins in 30,

In an hour it would use 750wh

That's about 18kwh in a day.

If you can't measure you can't optimise.

keno-daytrader

https://www.boards.ie/discussion/comment/121493184#Comment_121493184

Something in your setup seems way off, are you sure those are the correct flow temps? Yesterday you used 42kWh, that seems absolutely mental to me, the weather the last week hasnt been that cold. Ive my flow temp at 27c and used 6kWh yesterday (just ufh) to keep the house at 21.5c I dont run the heat pump at night, it starts up in the morning again.

I purchased one of those laser temp guns to make sure my ufh was properly balanced everywhere, I found it a big help to identify temps across my floors and walls.

newhouse87

https://www.boards.ie/discussion/comment/121494586#Comment_121494586

I changed to fixed flow after reading your posts and im v happy with approx 12kwh ufh usage in these conditions to get house to21/22, but 6kwh your using is v impressive. How long are you running it for,and size of your house? Like when mine comes on at 11am it uses near 2kw alone to get up to my lwt of 29 and then modulates down so usage drops to 1 or below? Do you not see any spike in usage when first starting in morning?

Nelbert

https://www.boards.ie/discussion/comment/121493380#Comment_121493380

Been looking in to a few solutions. We've blinds that went in at the start of the year on main windows but the extension also has perimeter glazing around the top which looks great but I'm now considering the window tinting or blinds up there too (span of the high windows a challenge though).

I'm more concerned about the glare on my TV than the heat, open back door and place cools down, but doesn't make my TV experience better!

keno-daytrader

https://www.boards.ie/discussion/comment/121494796#Comment_121494796

I usually run the heat pump from 10-8pm, Ive found this works best for me, Im on a 24h plan, so maybe it would change if I had night rates, but for now I dont. My heat pump increases its flow temp slowly, so for the first hour or so it might be only 24 slowly increasing to 27-28 after an hour. House is 210sqm 2 story.

It took me a few winters to really see/tweak whats best for our house/situation.

newhouse87

https://www.boards.ie/discussion/comment/121495553#Comment_121495553

Yep i run similar in these conditions 11-9pm. 242sqm, im happy with 12kwh usage for heating and house 21/22 in the evening time and generally 20/21 following morning. my pump works flat out to get to lwt29 and then modulates down output. Def think if people can find lowest fixed flow to heat their house it would work better and be cheaper then weather comp but all installers and experts are adamant about weather comp. Currently trending towards 30% lower usage for period nov to jan this winter by having no zones and lowest fixed flow.

keno-daytrader

https://www.boards.ie/discussion/comment/121495618#Comment_121495618

Yeah weather comp didnt work great for me. I think its probably better on the continent where there are big swings in temperature, we have a very moderate weather pattern with low swings in temperature for the most part.

paddyman

Hi guys,

Mitsubishi Ecodan have a heatpump with model number: PXZ-5F85VG. My plumber has recommend it as part of a retrofit with UFH we are doing on a bungalow. He advised that it can also perform cooling (with extra indoor wall units) as well as do my UFH/DHW.

I like the idea of been able to add cooling in future if it was ever required.

Does anyone have any thoughts on the model?, Any downsides for its primary roles of UFH/DHW?.

Thanks,

Paddy

championc

I think it's down to whether it's sized correctly based on the heat loss of the house. It's an 8.5kW unit. I think it will function exactly as he has told you, but as you might see from others, if not done right, can cost a fortune to run.

Eleusis

https://www.boards.ie/discussion/comment/121497305#Comment_121497305

I have the non cooling ecodan. I wish I went for the cooling version for heatwaves in the summer, especially if you have solar too. IMO if you had UFH you wouldn't need any casettes for cooling. Cold floor would be enough to take the edge off during heat wave.

Anyone know is it the indoor or outdoor unit that dictates if it cools too? Or both? I'd consider upgrading in the future if it was just the outside unit.

johndoe11

Anyone any idea where I would pick up a few of these? They are M28 manual actuators for underfloor heating manifolds. Can't seem to find them online.

graememk

https://www.boards.ie/discussion/comment/121555175#Comment_121555175

Do they operate in the same way as TRV Valves?, more pressure means more open?

johndoe11

Not sure about that, the more I tighten the less the flow on the sight glass, the pin moves down. I'm going to use these instead of stats, try to get an even balance throughout. Half my system has these, the rest are using room stats. I've been reading swedish varmepumpsforum.com , most there say it better to control temps using the manifold rather than room stats. Open all stats fully then try to get a balanced temp throughout.

graememk

https://www.boards.ie/discussion/comment/121555473#Comment_121555473

I had it backwards!, More pressure is less flow, Like you said.

If your finding no joy, It shouldnt be too hard to design and 3d print something. I should have a old trv from the radiator that i replaced that was m28*1.5 thread.

If you know any plumbers they might have a few lying about... I know 1 came with the last TRV i fitted but No idea where it is now.

graememk

https://www.boards.ie/discussion/comment/121555473#Comment_121555473

maybe something like this? https://www.ebay.co.uk/itm/125911738890

johndoe11

Yes, that looks like it would work. Cheers.

gandalfio

Can heat pump outdoor units/their fans be affected by snow?

dominatinMC

https://www.boards.ie/discussion/comment/121568559#Comment_121568559

Yes. The fact that snow forms at 0deg and below is one issue - meaning the pump is working harder to provide the temperature lift, but the practical implication of snow is that it can accumulate around the outdoor unit, ultimately blocking the air flow through the unit and compromising it.

gandalfio

https://www.boards.ie/discussion/comment/121568824#Comment_121568824

What can be done to avoid this?

graememk

https://www.boards.ie/discussion/comment/121569123#Comment_121569123

I don't think it's an issue, it would be similar to frosting that can occur when temperatures are low especially between 0 and 4 degrees

Heatpumps have an auto defrost function that clears the frost when required.

pic was just before a defrost happened.

Eleusis

im guessing you would have to dig the snow away so it wasnt obstructing the front or back of it. this is a once in a few years accurance in ireland though to get enough snow to build up and settle around it

poker--addict

https://www.boards.ie/discussion/comment/121493427#Comment_121493427

How I estimate Heat pump is I know my summer (zero heating required) usage averages 22KW per day including heating hot water.

Then find your average usage in winter which for me is around 70-80Kw (cry myself to sleep), so 50-60KW of heat pump (and associated circulation pumps) per day. I also know that the small pumps use around 150-200KW per hour, so I know that about 8KW of the 50-60 is extra pumps, so the heat pump itself is around 42-52KW. House around 350sqm.

graememk

https://www.boards.ie/discussion/comment/121569368#Comment_121569368

Been saying it all along, something ain't right.

Although my house is half the size of yours, if you look at my stats, I'm only using 20-25kwh per day (with a scop of 3.5, so 70-100 ish kWh of heat needed)

I've asked this before, but in the winter is the house warm?

tugii20

Have you fixed error 95?

If so

How?

I am having same issue

Thanks

HotSwap

https://www.boards.ie/discussion/comment/121569368#Comment_121569368

22kwh of input to the heatpump even with a COP of 2.5 would be enough to heat about 1000L of 15c water to 60C. That seems like an awful lot of hot water.

I use a total of 400-500L of water per day in total (hot and cold) washing machine / toilets / showers / etc… everything.

Do you think you’re using 1000L of hot water? What temp are you heating the water to?

graememk

https://www.boards.ie/discussion/comment/121571955#Comment_121571955

I wonder there could be a backup immersion running or something like that.

22kWh would be a decent sized DHW tank

johndoe11

https://www.boards.ie/discussion/comment/121569368#Comment_121569368

Also, not sure not sure the pumps could be using 8kwh per day. The grundfos internal heat transfer medium pump is rated for max 70w in mine and rarely runs above 50%, the Wilo water circulation pump is only max 45w and runs constantly at about 60%.

HotSwap

https://www.boards.ie/discussion/comment/121572248#Comment_121572248

That would be good for about 400L of water; which seems a lot more possible. Maybe they do use 1000L of hot water.

HotSwap

https://www.boards.ie/discussion/comment/121572376#Comment_121572376

My boost pump; which runs intermittently any time any tap (hot or cold) in the house is turned on. Can use 800-1000w per day.

Im moving the washing machine to a location that is not boosted; which will make it run much less often.

I know it’s not a central heating pump; but just thought it might be interesting comparison.

poker--addict

https://www.boards.ie/discussion/comment/121569883#Comment_121569883

oh missed it if you asked...yes house gets to temp. 19 in bedrooms usually, 19-20 downstairs. I think what aint right is the setup/design. The video linked before where heat geek looked at an install with too many bits (pumps/buffer tanks) resonates with me. Its at a point now where i think i am best to suck it up and wait till it goes POP, before paying out 20k for a replacement.