Heat pump / inverter DIY

anthonykeates

So, has anyone claimed a grant against installing ASHPs (see my post #81)?

Question about pipe runs - a lot of the units say they will do a 15m pipe run for example. Would the longer the run is (ie from outdoor unit to indoor unit) outside the house reduce the efficiency as there would be more heat lost in the pipe run? So if I had the outdoor unit installed up against my shed which is about 3 metres away from exterior wall and then pipe goes in a trench and then up the brickwork to first floor level, would this effect efficiency?

richardc1983

If its more than 15metres in length yes it will. YOu will lose capacity and quite possibly the compressor may not be powerful enough to pump that distance.

The 15metres is to get the quoted capacity that your buying. ANy more and u may jeopardise that. Why would you want it installed against your shed? The outdoor unit will be pretty quiet if its an inverter and will probably make similar noise level to the flu of a boiler. You will hear a fan noise not really much mechanical noise as they are quiet compressors not much louder than a fridge!

richardc1983

I avent applied for a grant as I got the system installed off a friend at reduced price anyway but I did get the VaT reduction, its a good saving.

rothers8080

Just want to make an update to this, I installed and got the heat pump running myself.

Was a nightmare due to terrible instructions and a total lack of interest from local aircon engineers.

However I managed to work it all out just by trawling the internet, it was, in the end, very very simple to install and get working and I could do it again in a couple of hours - but the install manual was written in such bad English it was almost useless.

This is the future of heating - it's great, just pick up the remote and tell it what to do. Can't believe we don't have these in most houses in the UK!

PS it's MINUS 2 outside and it's easily keeping the open plan at 23 degrees (and we have 10foot ceilings).

Once again - AMAZING STUFF, fitting one in the barn right now and can't wait to fit the air to water one for underfloor in the bathroom

Total cost for the first unit and DIY fitting was about £470 all inc - or if you like the cost of one crappy night storage heater.

richardc1983

Craig welcome to the world of heat pumps!

How long has your unit been turned on to keep the 23C. I would say at night to leave it at 18C if your going to be in the next day so it doesnt have as much of a struggle to bring it back upto set point.

rothers8080

Yeah I've been turning it on and off as needed but will set up the timer system this week.

We have just been enjoying very cheap on demand heat through Christmas!

richardc1983

Inverter systems are cheaper if you just leave them running if you get too warm just set the temp lower. If you are turning on and off, it uses more electricity to get it back upto the required temp as it has to work harder and for longer. If you look at central heating it always burns at full whack anyway but inverter only works at full whack when its bringing upto set point. If you leave at a lower setpoint it pretty much just plods along at a very low speed and electricity usage. WHat kind of timer system are you using?

Cardew

richardc1983 wrote: »

If you look at central heating it always burns at full whack anyway

??????

What do you think modulating is then?

stevehead

craigix wrote: »

Yeah I've been turning it on and off as needed but will set up the timer system this week.

We have just been enjoying very cheap on demand heat through Christmas!

Well done Craig!

Do your units come back on the way you left them if you cut the power (intelligent restart), or do they just do nothing when you power up again?

@richard - I just knew Cardew would pick you up on that gas burner faux pas

rothers8080

It has a little timer built in to the remote, so I've just set that up (should be coming back on at 8am), but yes, if you kill the power it must have a nand chip which stores the settings as it remembers exactly what it was doing before the power was cut and just gets on with it as if it was never turned off.

Nice little unit for the price, COP is 3.9, I'll post the average running cost later in the month, I'm right on the edge of the Pennines in County Durham so we get some interesting weather here, but it's often 4-5-6 degrees during the day even in winter so it should work well.

Once it gets the room up to temp it seems pretty stable, I've put 12 inches of loft insulation down too (got a job lot on ebay for next to nothing, decided to use it all!).