Results 51 to 81 of 81
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01-03-2010, 09:05 PM #51
Re: Altherma frequent compressor cycling
A little off topic - is there a way to edit a post after it has been submited? Since English is not my first language I find it difficult to get the right words, then after rereading I would often edit something, but I can not find how to do it.
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01-03-2010, 09:13 PM #52
Re: Altherma frequent compressor cycling
My wife used to say you never listen to a word I say at least I think that what she said
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01-03-2010, 09:26 PM #53
Re: Altherma frequent compressor cycling
Without going to high expense, dampen the probe (reduced response time) Nothing to loose, all to gain!
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01-03-2010, 09:37 PM #54
Re: Altherma frequent compressor cycling
Yes, I already contacted my installer and he said he will come one of these days. If the machine was out of warranty period I would try it out myself, but in this case...
When it is done I will surely post the results back. In the meantime, has anyone got a contact to some Daikin support? Here we have only authorised resellers, noone from Daikin around....
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01-03-2010, 11:15 PM #55
Re: Altherma frequent compressor cycling
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01-03-2010, 11:25 PM #56
Re: Altherma frequent compressor cycling
Last edited by Gary; 01-03-2010 at 11:28 PM.
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02-03-2010, 08:28 AM #57
Re: Altherma frequent compressor cycling
Valves on 3 longest loops (cca 100m) are fully open, since they have the highest hidraulic resistance (and are roughly the same length) I think there is no point in closing their valves
On the shortest loops I did start with closed valves and then slowly opening them to avoid thermal short circuit.
The valves of radiators are opened just enough to get enough heating in the room (also to avoid short circuit through radiator)
This way I tried to make sure there are no thermal short circuits and the longest loops also get enough flow to hopefully provide the buffer tank effect also.
I have to say there are no cold spots in the house - the heating is nicely even everywhere.
I would suppose that if the short loops are too short to provide enough heat with same water flow as the longer loops, they would need a higher flow and I'd get a short circuit through them. However, the flow meters on the manifold indicate that flow through the short ones is lower than through longer loops - if those meters are to be trusted - I don't put much faith in them.
Here's recap of my situation - each floor has it's own manifold:
- 1. floor: 3x100m loops (living room, kitchen, dining room) + 2x50m loops (bathroom, hallway)
- 2. floor: 1x75m loop (bathroom) + 3x Korado type 22 radiator of heating surface of 12m2 each (2 plates 180x60cm with folded fins between them)
There are no mixing valves, motorised valves and such things - it is kept as simple as possible - everything gets the same water te mperature.
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02-03-2010, 08:38 AM #58
Re: Altherma frequent compressor cycling
Are you able to measure the temperatures, fairly accurately, on the flow pipe and return pipe under the Hydrobox, just near the valves, when the unit is on full power?
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02-03-2010, 09:04 AM #59
Re: Altherma frequent compressor cycling
Sadly no, I don't have a thermometer that is nearly precise enough to do such thing. Maybe I can get something in the afternoon, when I finish at work.
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02-03-2010, 10:33 AM #60
Re: Altherma frequent compressor cycling
altherma switches on for 2 minutes, starting with an higher compressor frequency and then gradualy reducing it, unitl it switches off at the end of this 2 minutes interval (since there is not enough heat demand).
When the outdoor is started the unit will enter start up control and operate with preset values for EEV opening, inverter frequency and pump control.
- Inverter frequency is limited to 55Hz 120secs then 70Hz for a further 80secs
- Preheat control may hold off the pump until desired heat exchanger temp is reached.
- The unit also incorporates a 3min anti recycling timer to prevent excessive tart/stops
- The water thermostat control sensor is R1T located between the heat exchanger and back up heater
As Frank suggested you could calculate an approx flow rate by checking delta T across the inlet/outlet water temps (normally around 5K)
- Switch off unit or lower set point to 25~30
- Start system when water temp is <30
- Temporarily increase set point to 40
- Wait for 10min to ensure system is operating at 100% capacity
- Check temperature difference across inlet & outlet water pipes at hydobox.
The 3 port valve for changing from DHW to Space heating (if applicable) must be a diverting valve not mid a position valve. It may be worth verifying the correct valve has been installed and is operating correctly (these are often miss wired)
.
Last edited by VRVIII; 02-03-2010 at 05:40 PM.
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02-03-2010, 07:37 PM #61
Re: Altherma frequent compressor cycling
Good idea.
Although your flow indicators are working the measurement of the return loop temperatures would help you to balance the system better. You may actually have a short circuit through part of the system which will encourage early compressor shut down.
With the system running, work from the index fully open circuit and compare with the next circuit. Adjust flow valve to achieve the same, or closely similar, return temperature. Proceed through the whole system until all returns are at the same temperature.Last edited by Brian_UK; 02-03-2010 at 11:19 PM. Reason: Spelling and meanings
Brian - Newton Abbot, Devon, UK
Retired March 2015
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02-03-2010, 07:57 PM #62
Re: Altherma frequent compressor cycling
VRVIII, has given good information on how the unit operates, thought there was some other smarts controlling this.
I would not waste your time measuring temps to assume flow rates, +/-50% really means nothing. Unless you know the actual Kw output then all very big guess.
Lets look at some numbers
House 20C, so coldest possible water return temp 20C, ambient 15C, heat pump is likely to be giving 10Kw of heat energy (not lower levels as rated conditions) Set point 25C at outlet of heat pump. Presume flow rate of 0.3L/S (mid point for these types of circ pumps) Temp rise would just less than 8C, unit will turn off.
From what has been said the machine has the ability for an external thermostat. What is needed is 2 thermostats wired in parrallel, one measuring ambient and one measuring return water temp (with adjustable diffs)
1; ambient lets say set at 8C above this becomes open circuit
2 return water temp, lets say set at 24C, above this becomes open circuit.
The unit setting is maintained at higher set point lets say 32C.
This will allow for extended run times, and prelonged off times, whilst reducing temp swings. At lower temps, the system will revert back to original operation, which works fine as is.
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02-03-2010, 10:02 PM #63
Re: Altherma frequent compressor cycling
Mad frigrie,
The nominal flow rate for a size 8 unit in heating mode 24 L/min, the flow switch will trip at around 12L/min.
The unit capacity can be found in the technical data book capacity tables, this gives unit capacities under various conditions.
i.e. ambient temp 7 CDB with a leaving water temperature of 35 C = 8.4kw (nominal)
If you divide the unit capacity by heat exchanger delta T then divide by 4.2 (specific heat value for water with no additives) = flow rate in L/s
i.e. 8.4(KW) / 5(ºC ∆T) / 4.2 = 0.4L/S X 60 = 24 L/min.
This would give a good indication of the flow rate providing the unit is operating at 100% capacity.
I could be wrong here but I’m sure there are room stats available which monitor room temp and slab temp, they have a self leaning logic to maintain an optimum room temp under various conditions.
Afternine,
What is the full model number of your Hydrobox?
What size of water pipes is connected to the Hydrobox? (These should be 28mm)Last edited by VRVIII; 02-03-2010 at 10:05 PM.
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02-03-2010, 10:24 PM #64
Re: Altherma frequent compressor cycling
Hi!
Here are the facts:
- indoor unit model is EKHBH008AA6WN, manufactured in 2008, serial number 3800475. On the sticker there is another code: 3PW41657-25A
- printed circuit board in indoor unit:
- has the code (similar but not the same as on the sticker): 3PW43696-1A (should they be the same?)
- lot number: 788ß (yes, this is the "beta" sign - I hope this does not mean "beta" board as in software)
- the main chip on the PCB has a sticker on it: VP00203 V016
Outdoor unit:
- model ERHQ008ADV3
- manufactured in 2008
- serial number J002291
Sanitary Water tank model: EKHWSS200-300A3Z2
Now for the measurements: I borrowed an Minolta Cyclops 300af thermal camera to do the measurements (this thing was $2000 in 2004!):
- circulation pump is set to middle speed
- outside ambient temperature: 9.5°C
- starting water temperature value on controller: 24.4°C
- starting temperature of return flow pipe measured with Minolta: 24.7 °C
- water set point: 45°C
after 15 minutes the values are:
- on the controller: 38.4°C
- heated water pipe (measured with Minolta): 32.3°C
- return water pipe (measured with Minolta): 27.1°C
Since the measured pipe temperature and controller water temperature differed greatly, I took a look at the thermometers on manifolds; both read about the same value:
- heated water 39°C
- return water 33°C
@Brian_UK
I tried to measure the temperature of each pipe that returns to manifold and I had a "control" pipe - one radiator was closed (no flow through it). All pipes had about the same temperature, the pipe that comes from closed radiator was 2°C cooler than others. I did not find a pipe that is significantly hotter than others. I'll measure again, since the camera is better suited for measuring temperature of flat surfaces, on roud surfaces it can get a reading way off.
From what I see I guess there is enough flow and no obvious short circuits. Oh, and I found a sticker on the wire that goest to the flow switch - it says "setpoint 8l/min +- 1l".
30 minutes after the test the water temperature was 26.5°C
@mad fridgie
when using additional room thermostat Altherma "forgets" about its own controll.
It seems to me it will be either the sausage fix or the software fix - the first being more likely
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02-03-2010, 10:25 PM #65
Re: Altherma frequent compressor cycling
Yes and No, (do not have manual) we are looking at 15 ambient water on at min 20C, so refrigeration capacity could be anything (basic principles indicate a 20% rise in heat of rejection), and is the machine running at 100% (there are likely to many things that effect the load profile, does it have predicitive load limiting, if so how, when is introduced) Yes at what speed is this pump flow rate, and at what water pressure drop. As it seems there is only one pump, it is driving through the heatexchanger, underfloor, rads and hot water. So it would expect that flow rate would be less, due to pressure drops. You can not use ratings as a guide unless you are at the rated condition. To make it worth doing to some level of reality real figures have to be used.
remember the system does work fine, the OP does seem to have a lot of understanding.
The question is "is there any way that the differential/deadband/reaction time/ramp period, can be adjusted", here lies the problem.
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02-03-2010, 10:40 PM #66
Re: Altherma frequent compressor cycling
Afternine, what great detail, I wish all could give this level of information. "welldone"
It would seem that you have a flow rate rate of around 0.35L/S which is OK.
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02-03-2010, 10:42 PM #67
Re: Altherma frequent compressor cycling
@VRVIII:
Outer diameter of pipes is 34mm - here is a picture of my setup (hey, the forum lets me put links in posts now!):
http://www.4shared.com/file/74458060.../hpim6992.html
As it seems there is only one pump
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03-03-2010, 02:13 PM #68
Re: Altherma frequent compressor cycling
The unit data book includes capacity table indicating capacity in kw at various ambient and water temperatures. However as you say it can be difficult to verify the unit is operating at 100% as the inverter controls incorporate various temperature and current limiting functions.
The question is "is there any way that the differential/deadband/reaction time/ramp period, can be adjusted", here lies the problem
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03-03-2010, 02:30 PM #69
Re: Altherma frequent compressor cycling
As far as I’m aware none of these are adjustable.
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03-03-2010, 09:04 PM #70
Re: Altherma frequent compressor cycling
Afternine,
It was only the hydrobox full model number I requested - EKHBH008AA6WN. This was to confirm which settings are available on your unit, the available setting can vary depending on series.
@mad fridgie
when using additional room thermostat Altherma "forgets" about its own controll.
If you connect an additional room thermostat the only Altherma controller functions that will be lost are space heating on/off button and space heating schedule timers.Last edited by VRVIII; 04-03-2010 at 08:27 AM.
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16-04-2010, 11:37 PM #71
Re: Altherma frequent compressor cycling
If you would like to reduce the capacity out of the machine and also reduce the compressor cycling, run the system on the night quite mode which will limit the upperlimit of the compressor frequency and also the fan speed which will also limit the capacity.
To run the indoor water pump continuously without a room thermostat you will have to isolate the unit, put a bridge wire across the thermostat terminals 1, 2 and 4 and turn dip switch 3 on on the indoor printed circuit board.
let us know how you go with this.
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16-04-2010, 11:41 PM #72
Re: Altherma frequent compressor cycling
i just looked at your pictures, have you installed the 3 port valve motor to the system? if you have not done this, this would also be why the unit is short cycling.
You have low resistance through the domestic hot water cylinder and flow = return will cycle the unit off...
have you installed the motor or do you leave the body in the mid position?
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19-04-2010, 01:29 AM #73
Re: Altherma frequent compressor cycling
Hi everybody!
Sorry for being quiet so long, but in the meantime we had all sorts of things going on, including tornado speed winds with gusts topping over 240 km/h - yep, I thought we'll be blown off with the house and everything - this time I was sorry for not building with brick and mortar, however, luckily everything is fine. And Altherma worked fine in such wind, with no problems, keeping us warm! I expected it to get maybe a fan error since the wind was full frontal into the outdoor unit, but it just kept going.
Now, about the Altherma's cycling - I spoke with the guy who installed my system and he is NOT favorable to the idea of the "sausage" fix. He says that all small Althermas (6-8 kW) they installed all run with no problems and that I just keep looking at it too much . He said they had a few compressor failures with the bigger ones (11-16kW) but the small ones run totally fine as they come from factory. So as long as the machine is in warranty period I have to keep it as it is (if I want to keep it under warranty - it expires in november 2011 ). So no sausage fix yet. Although this does not stops me from thinking that I could save a few thousand compressor starts and make it last quite a few years more, when the warranty will be long forgotten.
However, now, as the weather is getting warmer I'm even more disappointed in Altherma's software. There is a field setting 4.2 "heat pump off ambient temperature". When outside temperature is higher than the setting, Altherma effectively shuts down (not completely, the red LED stays on), but the circulation pump is off and everything else is off. I set the field setting to 15 °C (the factory default is 25°C), and this is what happened:
the outside temperature was around 15°C and the reading on the display alternated between 15.0°C and 15.5°C every second, so it did shut down and started up the circulation pump. Even worse! It did the same with the 3way motorized valve - switching it from domestic hot water to space heating and back! Why does it "play" with 3way valve I have no idea, since there was no need to heat the domestic water. And it did so every second!!!, until the temperature rised/fallen enough to make it decide what should it be!!! I could not believe my eyes when I saw this - I guess nobody at Daikin thought about too frequent state switching... Of course I immediately set the 4.2 field setting back to 25°C.
I think the Altherma's software is "only half baked" (I guess I'm a bit proffessionally deformed, since I'm a software engineer). However, I would never think that a company with a name as Daikin could sell something like this. It puts Daikin in a really bad light. If I knew how bad Altherma's software is, I would opt for a heat pump from a different manufacturer. I guess it is OK to keep things simple, but software THAT simple, without any state switching control, is just overkill.
@Brunstar
Thanx for tking a look at my pictures - yes, I have the motor on the 3way valve - the picture shown was taken during the system assembly. The motor was mounted by the installation guy, so I guess he put the motor on the valve correctly. I even checked it myself - I took the motor off the valve when it is in space heating position and the valve seems to be set OK - the way of space heating fully open and domestic hot water fully closed. I'm sorry I didn't take the picture with the motor off, but I may do it in future. I also thought of the thermal shortcut through the DHW some time ago, because when heating domestic water, the pipe that goes to space heating is also quite hot. This would indicate that the valve is not fully diverted in one/other way. Maybe the pipe just gets hot from the valve housing, since the pipe seems to be hot only near the valve, the further from valve the colder it is. I'll remove the motor and take a picture of the valve, so you guys can take a look at it if it is OK.
As for the suggestion of keeping the night mode, I thought of it also myself, however, sadly it does not make much/any difference. The only way to lower the cycling frequency I found so far, is to use the timer and make it work in intervals - but this is not the comfort I payed for.
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26-04-2010, 01:26 AM #74
Re: Altherma frequent compressor cycling
All I can say is get back to your installer, he needs to check with Daikin if this is normal operation. Do not let the installers pull the wool over your eyes your system doesnt seem to be operating how it should be.
I had many problems with my lg system such as short cycling and all sorts and it turned out it was short on refrigerant amongst other issues.
If all else fails contact daikin yourself as he should be an accredited installer for the altherma system.
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26-04-2010, 01:28 AM #75
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26-04-2010, 07:31 AM #76
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26-04-2010, 09:39 AM #77
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28-04-2010, 03:45 PM #78
Re: Altherma frequent compressor cycling
if it is a thermistor you can also often put resistors in parallel with it..
putting the correct value resistors in parallel will require that there is more temperature swing up and down.. (the Daikin will 'see' the temperature swings as narrower than they really are) this will basically allow for longer cycle times off and on....
-Christopher
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04-06-2010, 01:06 AM #79
Re: Altherma frequent compressor cycling
answer is simples.system requires 2 pump
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04-06-2010, 10:53 AM #80
Re: Altherma frequent compressor cycling
I have read this with great interest.
There are multiple issues coming to bear. Control, method of heat dissipation in the house, the behaviour of the weather compensation and heat pump sizing.
I wont tell you what I do for a living, but i can suggest that fitting a small buffer cylinder will largely make this go away.
Not complicated, cheap solution, tried, tested and reliable.
Good luck.
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29-10-2010, 11:03 AM #81
Re: Altherma frequent compressor cycling
any news about this interesting post??
Tks
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