Air Source Heat Pumps

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Which also supports the concept that most suppliers do not size an ASHP to provide all your heating in these conditions. For maybe 7-14 days a year you do as Cardew suggests, or you have built into the ASHP, auxilliary electrical heaters of 3-6kw. Then the system runs automatically as if it can always meet demand.
Obviously important to size the ASHP to meet demand without the auxilliary heating running for an acceptable number of days a year. So be realistic about what it can achieve at outdoor temperatures of +7, +2, 0, or whatever is right for your location.

richardc1983

craigix wrote: »

Even if you buy a unit second hand you can buy the pipework and still fit it yourself - just make sure the previous owner shuts the unit down correctly before removal (ideally you would be buying from an aircon engineer) and the gas is all still there, sealed in the outside unit.

Those clip on connections do make things quick but working with the cooper pipe is pretty cool once you are used to it - plus you can cut it to the exact length. A cheap vacpump can check you don't have any leaks before you release the gas.

Here is one of my indoor units, the cable you can see on it actually goes up to a plug socket at ceiling level. Everything else is behind the plasterboard. By sinking it in to the wall we essentially make ourselves a 'slimline' unit! Oh and that's an ecoair unit, which have the best display of any unit I've ever seen. Temp + energy use (a green bar) always visible - encourages you to drop by one degree and see how much energy is saved. Shame they are twice the price these days.

What kind of air off temps from the unit do you get?

Hold a thermometer to the air outlet for 5minutes and report back what air off temp you get.

Would be interesting to know as some units have lower air off temps but higher airflow to make up for it?

Do you run yours in low fan speed, I do because of the noise but mine are floor mounted units and I have one wall mounted like yours.

clockworks_2

Richard

What do the floor mounted units look like? can you post a Pic pls?


thanks

richardc1983

craigix wrote: »

Would it be possible to buy a second unit and put it in-line only to be used in conditions such as that? I've got a huge 9kw air-water unit which I've not installed yet.

Good idea, but I think if the unit starts to struggle on the few days we get like this (this year is an exception) he could supplement it with the gas fire or electric heaters.

richardc1983

clockworks wrote: »

Richard

What do the floor mounted units look like? can you post a Pic pls?


thanks

I have 2 of the floor mounted units, here is one under the window. The LG floor mounts are known as convertibles as they can be mounted on the ceiling also if you dont have wall space. I have two of these, this one is in the lounge in the bay window and I have another in my bay window which is always on low in winter and mainly used in summer for cooling.



Here is the wall mount unit, this is the latest installed and they are all run off the same outdoor unit that can have upto 4 units on, it is upto its max capacity though with the size of the indoor units on so I would struggle if I added a further one on and they were all running at the same time.

The 3 I have heat the flat fine without having to leave internal doors open, but I do anyway as like the hallway and small kitchen heated.

Our bathroom door stays open all the time anyway due to the type of door closer on it so gets heated anyway.



This is the outdoor unit I posted a pic a couple of days ago:




Heres a video of the outdoor unit in heating operation:

http://www.youtube.com/watch?v=-mUzYHEfQEY

Andy_WSM

richardc1983 wrote: »

Good idea, but I think if the unit starts to struggle on the few days we get like this (this year is an exception) he could supplement it with the gas fire or electric heaters.

Which I do

I have turned the pump off for the rest of the day. It wasn't going to achieve much today anyway, it's still -5C here and it hadn't even recovered the water I used for this mornings shower! I am watching carefully to make sure that it at least turns itself on to circulate the water when the system water gets cold to prevent freezing - it is supposed to do this, so seems like the perfect opportunity to test it out! At least I will know in the future when I go on holiday I do not need to worry about what the weather might do while I am gone.

I might leave it off until we see slightly warmer temps and fall back to the immersion heater and the gas fire (s) for a few days.

richardc1983

Heres another vid of it in defrost mode:

http://www.youtube.com/watch?v=6JZvqFWpA7U&feature=related

richardc1983

Andy_WSM wrote: »

Which I do

I have turned the pump off for the rest of the day. It wasn't going to achieve much today anyway, it's still -5C here and it hadn't even recovered the water I used for this mornings shower! I am watching carefully to make sure that it at least turns itself on to circulate the water when the system water gets cold to prevent freezing - it is supposed to do this, so seems like the perfect opportunity to test it out! At least I will know in the future when I go on holiday I do not need to worry about what the weather might do while I am gone.

I might leave it off until we see slightly warmer temps and fall back to the immersion heater and the gas fire (s) for a few days.

You say the system was keeping set points in the house so it must be coping to keep the place warm.

Perhaps just use the immersion for the hot water?

Andy_WSM

richardc1983 wrote: »

You say the system was keeping set points in the house so it must be coping to keep the place warm.

Perhaps just use the immersion for the hot water?

Before I drew off a tank of hot water this morning it was managing OK, once I gave it a tank of freezing cold* water to heat it struggled to get back up to set point - in fact, in 5 hours it hasn't got where it was this morning - only 1C cooler, but not there yet.

I'm happy to let it have a break for a couple of days rather than kick the !!! out of it!

As said, temps like this are the exception here - I doubt it will happen again in the life of this system actually! No point thrashing it for the sake of not spending £10/£20 on electric / gas.

*I have a rain water harvesting system & the water is stored in large insulated tanks outdoors - you can imagine this water is VERY cold right now!

samtheman1k

richardc1983 wrote: »

Heres a video of the outdoor unit in heating operation:

http://www.youtube.com/watch?v=-mUzYHEfQEY

Is that not mounted too close to the wall? I would of thought that that would of restricted the airflow into the back, thus reducing the efficiency. I don't know about the LG ones, but the Mit ones require a minimum of 30cm.