Air Source Heat Pumps

richardc1983

eugeneg wrote: »

I have a NIBE Fighter 2005 air source heat pump that the manual at
http://www.nibeonline.com/pdf/511517-5.pdf
says reqires up to 1750 cubic metres of air an hour. I have this in a single car garage and have drilled holes in the door to feed the required air. But have I drilled enough holes ?

How can I work out the area in square metres that is required to feed 1750 cubic metres an hour without the motor straining ?

This was the post I was trying to find earlier!!!

here it is!!!

Dont do it! lol

albyota

No. the system had been off for a while it will do 55 if I let it, but don't need to for UFH, the Hot water run is set at 60 degrees and does a lift three times a day. 45 minutes each time, early morning 5 til 5.45 am, then 10 AM then at 6pm as I only have a normal cylinder, not as efficient as the HE type with longer coil. its only minus 1.2 at the mo, but has worked as normal in minus 8 in Feb 09 its guaranteed to work down as low as minus 20

richardc1983

Yeh mines guaranteed down to -15C so these temps are nowt really even though u can hear it whirring away!!!

The mitsi is great kit very expensive I think but they are outstanding performers and very good at what they do.

Is it really nessasary to lift the tank 3 times a day I thought you only needed to do it once a week for Legionairres?

albyota

no, the 3 x lift is just to get the hot water we need, early morning for washes, washing hair, showers etc then to recover once we have all gone to work/school, as Mrs only works 3 days/week so moans if no hot water for stuff midday etc.., (was easier to set up on the programmer this way) then at 6 for washes /showers.....tch....women... the Immersion heater is timed to come on on saturday night for about an hour for thermal disinfection. by the way the system on its own with FTC was only £2K

richardc1983

Ah ok I understand now. So it only takes 45mins to heat a tank up, thats great!

How many showers would you get out of that?

albyota

theres only four of us here now and we could easily get three showers from a tank lift, but it don't tend to go that way, someone will probably have a shower in the morning, while others are washing hair / washes, other times if the teenagers are off out at night then evening showers are had, me.... I don't get a lookin, just a hose down once in a while.... (joking), showers are pretty much kept fairly short (all well behaved at turning off either side of soaping..etc.(saves water). at some stage this year I will be removing the solar thermal panels and will then connect both coils of the twin coil OSO cylinder together to get a much better yield from the ASHP.

richardc1983

So can you explain how the system heats hot water and does the UFH at the same time both with different set temps.

I assume theres some sort of valve in play?

Are you leaving the UFH on 24/7 during these cold temps or still using timer? If so what times do you have it on? What temps are you maintaining in the rooms?

albyota

No the Flow Temperature Conntroller (the Big White box) takes a 240v signal from the cylinder stat and you can set a different temperature for the hot water, whereas the normal room stat goes to a different terminal and you then set what temp you require for heating. you can't have heating on at the same time as hot water, this is why the DHW is timed to lift when heating is not required.

richardc1983

Ah rite ok I understand hmmm I would have thought it would be able to do both at the same time.

Are you leaving the UFH on 24/7 during these cold temps or still using timer? If so what times do you have it on? What temps are you maintaining in the rooms?

albyota

just seen your edit... although at this cold time the UFH is on all night until 5am when it goes off to allow the hot water to do its lift, but there are room stats in all the rooms, with night set back, so at 10.30pm it ramps back to 19 degrees all rooms, but wth UFH the temperature is pretty much held, probably drops 2 - 3 degrees, if the temp goes below this the unit just comes on and heats that loop/room via actuator on UFH manifold until satisfied then goes off....not sure about the constant cycling of the system but its been like for over a year now and hasn't hurt it.