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Thread: Strage Pipework Configuration
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02-10-2011, 12:55 PM #51
Re: Strage Pipework Configuration
If the World did not Suck, We would all fall off !
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02-10-2011, 12:57 PM #52
Re: Strage Pipework Configuration
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02-10-2011, 01:00 PM #53
Re: Strage Pipework Configuration
On a heat pump air conditioner the defrost is nearly (if not always) carried out by the hot gas method, i.e. the reversing valve is energised to flood the outdoor coil with "hot gas". As this coil will be 90% full of liquid it will be pushed down the suction line and has to be collected by the accumulator to protect the compressor - hence the accumulator must be able to hold the entire charge.
The difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 01:01 PM #54
Re: Strage Pipework Configuration
Systems with a thermostatic expansion valve (TEV), the
accumulator holding capacity should be approximately 50%
of the system charge.
from parker
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02-10-2011, 01:04 PM #55
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02-10-2011, 01:05 PM #56
Re: Strage Pipework Configuration
I could be wrong but....I always thought a suction accumulator should be sized for 50% of refrigerant charge and a liquid receiver was 100% of charge.
Cheers
StuTool's ? check ! Condom's ? check !
If you can't fix it , f*ck it !!!
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02-10-2011, 01:09 PM #57
Re: Strage Pipework Configuration
http://www.refrigerationbasics.com/1...eat_pumps1.htm
in defrost mode the liq still travels through the 4 way valve and creates cooling in the evap thats why ur indoor fan slows down whilst in defrost mode
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02-10-2011, 01:10 PM #58
Re: Strage Pipework Configuration
stu u are wrong,but u are correct! brownie point for u!!
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02-10-2011, 01:12 PM #59
Re: Strage Pipework Configuration
Thanks Install
have kept a copy of that, a useful bit of info Cheers
Hi Stu
as per 'Installs' link you would be correct mate on refrigeration systems
But it does not state clearly for systems with reverse cycle or for heat pumps
And 'Marc s' comment makes sense, would you agree ?
R's chillermanIf the World did not Suck, We would all fall off !
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02-10-2011, 01:13 PM #60
Re: Strage Pipework Configuration
Haha far from it CM,
Install, i've read what Parker say that and by the size of the accumulator that is fitted then i would say they have probably used one that is 30-50% of the entire charge but what happens if a componet fails.
The size of an accumulator is based upon the size of the error, and the likelihood of the error you think can occurThe difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 01:18 PM #61
Re: Strage Pipework Configuration
Haha far from it CM,
Install, i've read what Parker say that and by the size of the accumulator that is fitted then i would say they have probably used one that is 30-50% of the entire charge but what happens if a componet fails.
The size of an accumulator is based upon the size of the error, and the likelihood of the error you think can occurThe difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 01:21 PM #62
Re: Strage Pipework Configuration
irrelevant
Last edited by chillerman2006; 02-10-2011 at 07:51 PM.
If the World did not Suck, We would all fall off !
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02-10-2011, 01:23 PM #63
Re: Strage Pipework Configuration
you dont have the power to give fractions yet! haha-nike 123 give me a pic of a pint of guiness and a bird wrapped in duct tape- that wasnt frowned upon!!
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02-10-2011, 01:33 PM #64
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02-10-2011, 01:37 PM #65
Re: Strage Pipework Configuration
my bad
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02-10-2011, 01:37 PM #66
Re: Strage Pipework Configuration
Suction accumulators are also system specific IE you should not use a standard SA on a heatpump system due to the orifice size being to big and allowing liquid slugging to the compressor especially in heating.
http://www.henrytech.com/Tips/HT-TT14.pdf
Cheers
StuTool's ? check ! Condom's ? check !
If you can't fix it , f*ck it !!!
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02-10-2011, 01:40 PM #67
Re: Strage Pipework Configuration
irrelevant
Last edited by chillerman2006; 02-10-2011 at 07:51 PM.
If the World did not Suck, We would all fall off !
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02-10-2011, 01:47 PM #68
Re: Strage Pipework Configuration
I've heard half system charge as a rule of thumb for accumilator sizing.
JonMostly found in Oxfordshire, UK :)
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02-10-2011, 01:56 PM #69
Re: Strage Pipework Configuration
chillerman
Last edited by install monkey; 02-10-2011 at 08:31 PM.
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02-10-2011, 02:26 PM #70
Re: Strage Pipework Configuration
Thanks Marc
You've had one electrical fault and the other sounds like liquid flood back, i'm with install on this,these dx units must be held off in ambients below 16c, i know theres plenty of heat at the minute but i doubt that was the case before this week? If the units are required to run in lower ambients you've a sizing issue. I can't imagine a heat pump with no accumulator, so look at control strategy and airflow first, see Gary we do listen!!
alMostly found in the southern part of this green and pleasant land.
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02-10-2011, 02:32 PM #71
Re: Strage Pipework Configuration
hmmm-post missed with all the chat over accumulators-other points to consider-
no crankcase heater on the pot, system is within the airflow so exposed to 10-40deg ambient, no jacket on the compressor, as u say no suction accumulator or evap press reg, as with air handling units normally 100% fresh air then sticking a cooling coil in there there is not a constant load so theyve done well sticking an electronic expansion valve-at least it will be more responsive, also them check vavles will need checking to ensure theyre not passing as with the 4 way valve as its too easy to chuck a pot in and watch it destroy itself, also i would look at the control strategy, comp restart delay, setpoint differential it should have a free cooling setpoint that usually is set around 16 deg which will stop the mechanical cooling and rely on fresh air.
are the v belts ok,if fitted,panel filters blocked as they normally last 3mth also check alarm history, is there a lp swith on it or transducer, may be sartup of the compressor causing pipework to flex and the lp being auto reset??
are the fans inverter driven whats the minimum speed or is it controlled of duct pressure?
i could nip up to site as its in my hood!!haha
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02-10-2011, 02:51 PM #72
Re: Strage Pipework Configuration
Install
Just because no-one replied to your post the last time round
R's chillermanLast edited by chillerman2006; 02-10-2011 at 08:29 PM.
If the World did not Suck, We would all fall off !
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02-10-2011, 02:56 PM #73
Re: Strage Pipework Configuration
my post co
Last edited by install monkey; 02-10-2011 at 08:30 PM. Reason: cut out the adverts!!
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02-10-2011, 03:40 PM #74
Re: Strage Pipework Configuration
irrelevant
Last edited by MikeHolm; 03-10-2011 at 10:29 PM.
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02-10-2011, 03:46 PM #75
Re: Strage Pipework Configuration
molson per
Last edited by install monkey; 02-10-2011 at 08:29 PM.
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02-10-2011, 03:53 PM #76
Re: Strage Pipework Configuration
irrelevant
Last edited by MikeHolm; 03-10-2011 at 05:47 PM.
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02-10-2011, 03:55 PM #77
Re: Strage Pipework Configuration
irrevelant
Last edited by MikeHolm; 03-10-2011 at 05:47 PM.
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02-10-2011, 04:06 PM #78
Re: Strage Pipework Configuration
irrelevant
Last edited by chillerman2006; 02-10-2011 at 07:50 PM.
If the World did not Suck, We would all fall off !
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02-10-2011, 04:11 PM #79
Re: Strage Pipework Configuration
is that ur
Last edited by install monkey; 02-10-2011 at 08:29 PM.
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02-10-2011, 04:14 PM #80
Re: Strage Pipework Configuration
irrelevant
Last edited by MikeHolm; 03-10-2011 at 05:46 PM.
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02-10-2011, 04:15 PM #81
Re: Strage Pipework Configuration
irrelevant
Last edited by chillerman2006; 02-10-2011 at 07:49 PM.
If the World did not Suck, We would all fall off !
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02-10-2011, 04:18 PM #82
Re: Strage Pipework Configuration
irrelevant
Last edited by chillerman2006; 02-10-2011 at 07:48 PM. Reason: sorry marc
If the World did not Suck, We would all fall off !
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02-10-2011, 07:43 PM #83
Re: Strage Pipework Configuration
11 posts spamming.....
The difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 07:48 PM #84
Re: Strage Pipework Configuration
The difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 07:54 PM #85
Re: Strage Pipework Configuration
Check the accumulators for size and correct piping (inlet/outlet), could be worth getting a thermal camera for a day to see what's going on?
alMostly found in the southern part of this green and pleasant land.
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02-10-2011, 08:09 PM #86
Re: Strage Pipework Configuration
Not all compressors have visible crankcases though do they? Many of them have a voltage going through the windings to heat the compressor a few degrees.
Minimum air onto these coils/compressors is 18DegC
Compressor restart delay is 6 min. These have a recouperator that mixes fresh air and return air and if the temp is still too high/low then the compressors will be brought on. The setpoint for the building is 21/22 degress C so the compressors don't need to be on often....supposedly.
Filter/belts ok
Yes theres an LP switch on it, looked at alarm history and found only the 1 LP fault.
Compressor flex and reset the LP alarm ?? Can that happen??
Yes the fans are inverter driven and have been commissioned to run at 50hz
Lol, Nip up to the site to do what?The difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 08:12 PM #87
Re: Strage Pipework Configuration
Thermal camera? To check what?
The difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 08:17 PM #88
Re: Strage Pipework Configuration
check the accumulator for a start, also check your 4 way valve and NRV's.
In fairness this is either the site completely screwing up the units or they have been misapplied or specced?
alMostly found in the southern part of this green and pleasant land.
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02-10-2011, 08:29 PM #89
Re: Strage Pipework Configuration
Copeland say that the scroll is compliant, it can handle liquid flood back ( a slug of liquid), say after defrost, in this case it is the position of the EEV temp and pressure sensor causing prolonged oil dilution,
Accumulator size, without knowing all the data I would just go for one which is has the same size pipe as the comp inlet. You could even look a suction/liquid line heat exchanger (between the EEV sensor and the comp)
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02-10-2011, 08:36 PM #90
Re: Strage Pipework Configuration
MF, i've found scrolls less tolerant of flood back, more inclined to wash oil out and not return it, accumulator would be essential as you say.
alMostly found in the southern part of this green and pleasant land.
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02-10-2011, 08:40 PM #91
Re: Strage Pipework Configuration
Thats a good idea al, I may suggest that.
When i find out more i'll update the thread, thanks for your input. Much appreciatedThe difference between genius and stupidity is that genius has its limits.
Marc
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02-10-2011, 09:03 PM #92
Re: Strage Pipework Configuration
Gents
just a quick thought as bed time for me
dont certain copeland scroll models have built in accumalators that allows them to take full liquid and boils it off by compressor heat ???
R's chillermanIf the World did not Suck, We would all fall off !
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02-10-2011, 09:23 PM #93
Re: Strage Pipework Configuration
Before I starting producing my units, I did considerable testing on the scrolls, and found that under certain circumstances liquid return was a problem, so even though the tech data says i do not need a accumulator, I do fit one, in my mind it is cheap protection.
CM; copeland scrolls do not have a built in Acc, Maneurope recip comps do. (twin shell)
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03-10-2011, 06:10 PM #94
Re: Strage Pipework Configuration
Thanks Mad
Thought I was going 'mad' when the thought appeared in me head, argh so its maneuropes (recips) Cheers for correction
Also picked up a site with a right mickey mouse abortion of a setup (1st visit today) with 4 copeland scrolls, it looks a right b*tch to change 3 of the four compressors
Mad, in your eyes, whats the perfect suction superheat for copeland scrolls (as I need them to purr for ever)
R's chillermanLast edited by chillerman2006; 03-10-2011 at 06:24 PM.
If the World did not Suck, We would all fall off !
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03-10-2011, 07:03 PM #95
Re: Strage Pipework Configuration
Is anyone doing a failure test on the failed compressors
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03-10-2011, 07:17 PM #96
Re: Strage Pipework Configuration
Can Copeland Scroll compressors handle liquid?
ANSWER: Scrolls handle liquid better than most other compressor types, but still can require additional accessories for optimal protection. Those accessories include: Accumulators are recommended for systems with large refrigerant charge or those that allow for uncontrolled refrigerant floodback. Crankcase heaters are required for three-phase systems with large refrigerant charge and in/outdoor applications. ref copelands website
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30-10-2011, 09:47 PM #97
Re: Strage Pipework Configuration
Just to update the thread. The system was found to have a leak on the equalising line. The manufacturers went back to site to repair.
Thanks to everyone who contributedThe difference between genius and stupidity is that genius has its limits.
Marc
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30-10-2011, 09:54 PM #98
Re: Strage Pipework Configuration
Nice one Marc, thanks for the closure!!
alMostly found in the southern part of this green and pleasant land.