Air Source Heat Pump

QrizB

115 in the model name means 11.5kW nominal capacity, IIRC.

matt_drummer

Spoonie_Turtle said:

matt_drummer said:

Spoonie_Turtle said:

I've just checked our usage (needed to anyway, but this thread reminded me) - ours is from 2019, and heating apparently used 66kWh in July and 70kWh in August, for outputs respectively of 0kWh and 13kWh.

Thankfully the cost isn't horrendous as we're on Tracker with a low average unit rate, but I am gobsmacked at the wastefulness.  It's even worse than last year (34 and 50kWh used for 'heating' in those two months, for 0 output).  But the smart meter data doesn't shed any light, the only spikes are heating water or otherwise explained by our activity.  Unless it really is just a constant vampire load.

I don't know if I even have the courage to turn it off next year though - I live here but my parents are the tenants, and the heat pump was put in by the HA.  I really don't want to make anything go wrong!

Where are you getting this information from?

What heat pump do you have?

Do you use it to heat your hot water?

My standard Daikin monitoring is good but not detailed enough for me.

I will be having a more sophisticated monitoring system fitted soon (something that Octopus could have fitted at the installation but never offered but that's another story, a bit annoying) but in the meantime I have fitted a ct clamp monitor to the supply cable of the heat pump.

The ct clamp monitor has two inputs so the other is connected to the supply to the house. This means I can cross check with my solar monitoring and energy account and reconcile the total to make sure my figures for the heat pump are correct.

I don't think 2 or 3 kWh a day of standby costs are acceptable, I wouldn't be happy with that.

A ct clamp monitor is pretty cheap and easy to install.

My heat pump is on a separate supply in my meter cabinet so I can turn it off there or at the isolator switch next to the heat pump.

I would try turning it off if I were you, it's no different to a power cut, I can't see what could go wrong.

Ooh good point.  Though our power cuts are not quite that prolonged.

I'm getting the info from the … I don't know what it's called.  This, on our hot water cylinder, the panel that controls everything

Yes we do use it for hot water (that August usage of 33kWh delivered 96kWh for hot water - thanks to our smart meter information I know that yes we definitely need to turn it off when we go away as it heated it every day despite none being used *facepalm*)

It's a Mitsubishi Ecodan, 9.5kW I think?  I have an old thread where I put all the info, lemme dig it out … ah, PUZ WM115VAA  (I think the VAA stands for Vaampire … !)

The heat pump won't know how long the power has been off, it doesn't matter whether it is a few minutes or a few days, it will never know.

 Did you intend your heating to be on in August?

When you are away the heat pump is only bring the tank back to it's set temperature from natural losses, it won't have used much.

When we were away in July and not using hot water I could see that our tank loses around 0.1c per hour, it's not much.

Spoonie_Turtle

matt_drummer said:

Spoonie_Turtle said:

matt_drummer said:

Spoonie_Turtle said:

I've just checked our usage (needed to anyway, but this thread reminded me) - ours is from 2019, and heating apparently used 66kWh in July and 70kWh in August, for outputs respectively of 0kWh and 13kWh.

Thankfully the cost isn't horrendous as we're on Tracker with a low average unit rate, but I am gobsmacked at the wastefulness.  It's even worse than last year (34 and 50kWh used for 'heating' in those two months, for 0 output).  But the smart meter data doesn't shed any light, the only spikes are heating water or otherwise explained by our activity.  Unless it really is just a constant vampire load.

I don't know if I even have the courage to turn it off next year though - I live here but my parents are the tenants, and the heat pump was put in by the HA.  I really don't want to make anything go wrong!

Where are you getting this information from?

What heat pump do you have?

Do you use it to heat your hot water?

My standard Daikin monitoring is good but not detailed enough for me.

I will be having a more sophisticated monitoring system fitted soon (something that Octopus could have fitted at the installation but never offered but that's another story, a bit annoying) but in the meantime I have fitted a ct clamp monitor to the supply cable of the heat pump.

The ct clamp monitor has two inputs so the other is connected to the supply to the house. This means I can cross check with my solar monitoring and energy account and reconcile the total to make sure my figures for the heat pump are correct.

I don't think 2 or 3 kWh a day of standby costs are acceptable, I wouldn't be happy with that.

A ct clamp monitor is pretty cheap and easy to install.

My heat pump is on a separate supply in my meter cabinet so I can turn it off there or at the isolator switch next to the heat pump.

I would try turning it off if I were you, it's no different to a power cut, I can't see what could go wrong.

Ooh good point.  Though our power cuts are not quite that prolonged.

I'm getting the info from the … I don't know what it's called.  This, on our hot water cylinder, the panel that controls everything

Yes we do use it for hot water (that August usage of 33kWh delivered 96kWh for hot water - thanks to our smart meter information I know that yes we definitely need to turn it off when we go away as it heated it every day despite none being used *facepalm*)

It's a Mitsubishi Ecodan, 9.5kW I think?  I have an old thread where I put all the info, lemme dig it out … ah, PUZ WM115VAA  (I think the VAA stands for Vaampire … !)

The heat pump won't know how long the power has been off, it doesn't matter whether it is a few minutes or a few days, it will never know.

 Did you intend your heating to be on in August?

When you are away the heat pump is only bring the tank back to it's set temperature from natural losses, it won't have used much.

When we were away in July and not using hot water I could see that our tank loses around 0.1c per hour, it's not much.

Length of time off: true, but I think I'm worried about something seizing up or it not being able to pick up the connection between controller and heat pump (something that randomly happened in winter so we were without heat or hot water for a few days until an engineer could fix it.  Thankfully the snow held off until after it was fixed).  I also don't know what it's using all that power for, to know whether it'll be okay off for a prolonged time or not.
 I guess with the hot weather this week, it's the best chance to try - if my parents are okay with it.  It's clear we don't understand enough to troubleshoot when things do actually go wrong.

Heating: no, I thought I turned it off but evidently not - must have thought it wouldn't need to kick in during August (it's set to kick in if the house drops below 18℃ in the daytime).  Now I know we can have a cold summer as well as heat waves.

Water: consistently the smart meter data shows it using an extra 0.75-1kWh above the base load, every day, at the time the hot water is allowed to kick in.  Not a huge amount, granted, but far more than was needed while the house was empty for two weeks!  And actually about the same as when we have been back and using the hot water.  A bit ridiculous, but not as ridiculous as the "heating" consumption.

Concorde12

Hi there I'm new to ashp ..I have one in my new home an LG make ..I'm alone so how do I switch off the water I only need it to shower and it's set to be on all day???

Strummer22

Concorde12 said:

Hi there I'm new to ashp ..I have one in my new home an LG make ..I'm alone so how do I switch off the water I only need it to shower and it's set to be on all day???

If you search online for the make and model + manual, you should be able to find a copy of the manual online. This will tell you how to navigate the menus to change the settings.

However, heat pumps don't work like combi boilers. Assuming your central heating is off, it will heat up your hot water tank to whatever the set temperature is, and then do nothing until the temperature in the tank falls below some set value. That will either be after you've used a significant portion of the water in the tank, or it has cooled down through losses (maybe taking 1-2 days). 

You'll not save much money by setting the hot water to only come on at certain times. But given that this is money saving forum, it is true that there are some savings to be had by setting it to only heat up the hot water tank in the afternoon when the air is warmest (or when your electricity is cheapest, if you have solar). Or you could set it to do it overnight if you have a cheap night rate.