Way off topic: Heatpumps

[deeveus 81]

In 2007 we bought a Panasonic CS-E18FKR & it wasn't an elcheapo at the time, was more than 3k. We had someone up to measure the place and he said this one would be fine, so we said we want the model above it so we went with the higher output model. We have a multi-fuel fire which we use at night. We live 300m above sea level. Our heat pump is ratshit, it went into defrost at 7 degrees outside temp and the sun was shining on the unit.

So either the machine is rubbish or it needs serviced or replaced? I thought about taking it out and getting a Daikin installed and putting this Panasonic in our other place. I constantly clean the filters but it doesn't make any difference. Does anyone here know much about these?

Full specs here: Panasonic

Edited July 23, 2012 by The Diesel Guy

[BM WORLD 1283]

does it have enough gas in the system??

filters clean , outside unit mounted on the correct side of the house and with plenty of ventilation around it.

cooling fins clean , fan working at full speed etc

[_ethrty-Andy_ 2132]

mines a panasonic, its the middle model cant remember the model number off hand.

have also noticed it was a bit hit and miss, and then realised it was when i had the E30 parked about a meter in front of the unit that it didnt work as good as it did when it wasnt there and parked by the gate.

[Dave@nz 11]

Hi,

Mine is a Fujitsu ducted system, performance in frosty conditions is average and if it is started up from scratch in a frosty morning with the inside fan set at high or medium it will frost up and go into default mode.

I have heard that the mitsubishi Hyper core series are able to cope well in cold conditions but I have not researched that. Daikin has a good rep as well.

I have had a look at your unit spec and see it is rated at 6.8kw and should heat a room of approx 7-8m square.

http://www.airconnz.co.nz/Heat-Pumps-types...lculate__I.2076

Dave.

[deeveus 81]

Hi,

Mine is a Fujitsu ducted system, performance in frosty conditions is average and if it is started up from scratch in a frosty morning with the inside fan set at high or medium it will frost up and go into default mode.

I have heard that the mitsubishi Hyper core series are able to cope well in cold conditions but I have not researched that. Daikin has a good rep as well.

I have had a look at your unit spec and see it is rated at 6.8kw and should heat a room of approx 7-8m square.

http://www.airconnz.co.nz/Heat-Pumps-types...lculate__I.2076

Dave.

That's a good site, ours comes up as saying 115m3, it's a larger area due to open plan. But with the ours being rated at 6.6kw and only being 6 degrees outside at the moment it's struggling to give us 20 degrees. Crank up our fire on half and it will put the whole house up to 22 degrees even when it's -2 outside!

[elmarco 56]

I personally don't like the Panasonic heat pumps. My parents have one and have a similar complaint with it having to go into a defrost cycle when you first start it in the morning (and this is in Auckland...) - they say it is expensive to run ($40/$50 per month on top of the normal) and their house is already a particularly warm house. I also had one at my last job where the fan & motor were replaced once, and were on the way out a second time within 18 months.

I have had a Daikin at home for the last 7 years. It's been brilliant, but is now getting noisy bearings in the fan/motor. No problems with it going into a defrost when you need it most.

I found the major problem was getting a highwall unit that isn't offensive to look at. I see Daikin no longer make my one (which was the only one in their range I liked). Think if I had to put another one in I would most likely go with a Mitsubishi - the performance is right there with the Daikins, and they look quite sharp.

[MLM 57]

Would have thought that being a refrigerant circuit where heat is rejected from the inside heat exchanger which has hot compressed gas in it to warm you up and the outside bit gets cold and accepts heat from the ambient air.

The defrost cycle on start up would be the systems way introducing heat quickly into the system so it could warm up the inside quicker or gets the refrigerant sat in the evaporator outside moving into the system

Its possible the system has the incorrect gas amount in it. Either to much or too little. I assume an installer would add this to the system separatly once its installed making it possible to get wrong.

E: Its probably also worth noting that when its -2 outside there isnt a whole lot of heat available to "pump" into the home from the outside which the system is trying to do, so poor performance at this end of the opperating window probably won't be flash

Edited July 24, 2012 by MLM

[RvT 9]

Not quite off topic but when you talk to different heat pump companies, there is usually a preference by the seller for one brand over another. While this is possibly not applicable to all companies, it is applicable to most. While they may have all the brands for sale in the showroom, you will find that the reseller has a preference for one brand over another. The reason for this is because the more they sell, the better the margin they get plus if they sell X number of heat pumps, they get taken on all expenses paid trips overseas like USA etc. I have a friend who is a reseller / installer and he usually prefers one brand over another and every year, his annual holiday is paid for by his 'preferred' supplier of heat pumps.

What Clinton is doing is the best method which is to do your own research before walking into a shop and tell the reseller what model you want.

GT Radials has a similar scheme but that is more based around 'giving' the tire place a ute provided he sells x number of sets of GT Radials hence why there are a few GT Radial ute around ...

[kiwi535 538]

Not quite off topic but when you talk to different heat pump companies, there is usually a preference by the seller for one brand over another. While this is possibly not applicable to all companies, it is applicable to most. While they may have all the brands for sale in the showroom, you will find that the reseller has a preference for one brand over another. The reason for this is because the more they sell, the better the margin they get plus if they sell X number of heat pumps, they get taken on all expenses paid trips overseas like USA etc. I have a friend who is a reseller / installer and he usually prefers one brand over another and every year, his annual holiday is paid for by his 'preferred' supplier of heat pumps.

What Clinton is doing is the best method which is to do your own research before walking into a shop and tell the reseller what model you want.

GT Radials has a similar scheme but that is more based around 'giving' the tire place a ute provided he sells x number of sets of GT Radials hence why there are a few GT Radial ute around ...

i tried to get a heat pump put in ,but both people who came round to "quote me knew less about heat pumps than i did after a bit of internet research..have now decided i dont want one after experiencing them at work.You walk into he room which feels warm having a forced air heating ssytem i reckon is just wrong.Gimme radiat heat anydayOat least a component ...pellet burner for me

[my_e36 43]

I have a Mitsubishi Electric heat pump, really quiet and cheap to run (around $10-15 extra per month, 3-5 hours per day avg, 5.4kW heating model). Mind you, I am in Auckland and wasn't "THAT" cold but never have trouble giving warmth first thing in the morning. Never seen frost on the outdoor unit either.

[deeveus 81]

Do you guys get frosts up in Orklind? Can't be too good if heatpumps are going into defrost mode up there huh?

[MLM 57]

Yup frost happen up here but not every night in winter.

Out of curiosity why is it deemed a bad thing if it goes into defrost mode?

[deeveus 81]

Yup frost happen up here but not every night in winter.

Out of curiosity why is it deemed a bad thing if it goes into defrost mode?

Because the machine stops working for sometimes up to 5-10 minutes and in that time it's not producing any heat at all inside - if it constantly does this it's either not working correctly or not fit for the room size.

[MLM 57]

Ok thanks, I dont own a heat pump so am unfamiliar with their opperation.

As someone who has an idea about refrigeration circuits though im not convinced a heatpump would work particularly well in cold humid conditions typical of NZ. If its cold outside there isnt much heat available to pump inside and chances are if its cold its going to be wet too. Perfect conditions to ice up the system.

Therefore it will require regular defrosts to maintain airflow through the evaporator. if the system dosnt take advantage of the defrost source of heat and keep running to help the inside warm up you wonder if somthing has been missed in the design. Sort of a special mode of operation until it gets warm inside..

Anyway, hope you can suss it out

[shaneg 0]

We have a Panasonic at my place, works great and its regularly -5 outside were its located, we get f.a sun at the mo.

Works right up to 31°c output no prob.

Although the last place i was at had the same model and was shithouse.

Could just need a good service?

[deeveus 81]

We have a Panasonic at my place, works great and its regularly -5 outside were its located, we get f.a sun at the mo.

Works right up to 31°c output no prob.

Although the last place i was at had the same model and was shithouse.

Could just need a good service?

Just as I'm reading this now it's exactly 20 degrees in and 1.5 outside and it's just gone into defrost.

Reason for not having the fire on is because we were out for birthday turned it on at 4pm at 22 degress asking, got home an hour ago and it was 20 inside. It does work but fark it must be raping some power!

Edited July 25, 2012 by The Diesel Guy

[shaneg 0]

That sucks, we have ours on from 4pm until 12. our bill is about 420 a month..

[leithcm 0]

I'm in Christchurch, and we are having a really cold winter this year. Plenty of frosts - and down right miserable, bitterly COLD days with low overcast. We have a Mitsubishi 10 kw unit - just the one feeding into a underfloor ducted system. Trick is with these is to have the underfloor ducting FULLY insulated - ours is with a silver backed "pink batts" about 5 cm thick. The system heats the whole house - it is a 53 year old home, about 250 m2, with no wall insulation but good ceiling. The temp is set to 20 deg, and the place is toasty-pie warm - all the time. Monthly power bills? About $355 to $380- but we run night and day rate tarriff system, about 700 - 800 KWH per month for both tarriffs. I think the Mitsubishi is an excellent system, better than a lot of the others that are designed to cool rather than heat. Just my 2c worth.....

[MLM 57]

Just as I'm reading this now it's exactly 20 degrees in and 1.5 outside and it's just gone into defrost.

Reason for not having the fire on is because we were out for birthday turned it on at 4pm at 22 degress asking, got home an hour ago and it was 20 inside. It does work but fark it must be raping some power!

This is probably the worst case situation for a heat pump. Its cold and its damp, defrosts are going to be a regular and annoying fact of life. It it were a few degrees below zero the humidity would be far less as any moisture in the air is now now sat on the ground as snow. If it were a few degrees warmer you would get more heating benifit before a defrost untill its warm enough inside and it can defrost naturally as part of its heating off cycle.

[my_e36 43]

Stupid thought: light a camp fire near the outdoor unit.

[rusteee 52]

Just to add my 5c =D we've had quite a demand for heat pumps in the last few weeks, and they really all do vary in the frosty mornings. The units with the smaller outside evaporators are usually the worst, the fan speed is so high and the evaporator so small, it frosts up really quick. Mitsubishi is probably the best overall with the smaller inside evaporator and the large outdoor unit with lower fan speed, seems to keep the heat pouring out in the frost. Best thing with a unit that cant keep up is to keep the thermostat set to something realistic (say 16 degrees if its minus 2 outside), and dont have the fan speed flat out, have it set to say mid scale. This way it will slow the heat exchange down and prevent the outside unit frosting up so soon, but still bring adequate heat from the inside unit. Once its caught up then set it to your comfy temperature. Alot of people make the mistake of just cranking them to the max, turning the outdoor unit into an iceblock before it has a chance to defrost.