maylaysia

[rbartlett]

Hi guy's

got a phone call from a friend who works for a telecomms comapny
they have a mobile station which has an a.c with a gas leak.

none of the locals want the job for some reason.

no real money in it -just a few quid plus all expenses and a nice trip to the sunshine

anyone interested as i have to put together a package for him > i don't know the kit but he's faxing over the spec

cheers

richard

[frank]

Hi guy's

got a phone call from a friend who works for a telecomms comapny
they have a mobile station which has an a.c with a gas leak.

none of the locals want the job for some reason.

no real money in it -just a few quid plus all expenses and a nice trip to the sunshine

anyone interested as i have to put together a package for him > i don't know the kit but he's faxing over the spec

cheers

richard

With your web published rates I'd have thought that this would be a nice little earner (tried to post a smilie but webram seems to have turned them off :-))

[rbartlett]

well guy's looks like you missed a real treat..

a nice trip out on air malaysia and a stay at the plaza

http://www.ichotelsgroup.com/h/d/cp/1/en/ha/kulcp

a bit of cash and all expenses paid !!

the work will be handled by the more than competent bersaga

http://www.refrigeration-engineer.co...tposter&t=2482

and you would have just been there as the company representative..

still, I shall enjoy it far more than you miserable buggers !!

cheers

richard

[Abe]

You deserve a trip out there Richard, you will love it........Have a great time and take care
All the best

Abe

[rbartlett]

Hi guy's

sitting in the hotel lobby in downtown K-L;-)

The place is very nice and the people are fantastic. My contacts Bernard (from this board) and Charles (in K-L) are a real couple of great guys....

I shall be discussing this further with them as we shall be meeting but here's an interesting one..

one one of the rigs the customer complained that it wasn't as cold as it should be

it's a simple mobile split scroll comp condenser under cabin evap in compartment.R407c

no fancy stuff and just a basic on/off stat -no hotgas BP liq inj or that sillyness

let it run

pressures suction 60
discharge 290

just sweating back but certainly not 5 deg superheat (no dig thermo to prove....)

although it's a tad high disch I thought it was short of gas (remember that it was 33 deg's today here) 60psi and 15(?) s/h

however as were discussing this the suction went up to 110 psi and the discharge dropped to 250

then after about 4-5 minutes went back to 60/300 this seemed to cycle like this for at least 1/2 hr

any idea's in action??

We have ordered two additional condenser fans to improve ventilation and we are going to remove the ref and re-charge with fresh at correct weight tomorow but thought I'd run it past you guy's

cheers

richard

[Temprite]

Hello Richard.

Had a LG split recently with similar symptons. Instead of a bypass valve and solenoid, it had a bypass valve inside the compressor.

It would operate with relatively normal pressures then suddenly the suction would go up and the discharge would drop.Then it would return back to normal.

Initially I thought the compressor valves might have been shot, but Lg Tech support informed me of the bypass valve in comp.

Changed comp. All o.k.

[rbartlett]

well firstly i must say it's a rotary not a scroll however there are two units and both are doing it!!

now to add to the mystery

if we fully charge the systems as man's plate = 650 gms
disch 300
suct 60
rated amps 6.6
running amps 5.8

ambient 35 -ish

runs 10 minutes(ish) then bypasses suction rises and disch falls...
running amps drops to 2.2

turn off and switch back on cycle repeats -runs great -then bypasses

we have a hunch that the condenser is undersized due to the tropical conditions plus it's situated tight under the body of the truck so -

put cold water running on cond -disch drops to 225

runs absolutely great -off coil temp 9 deg's and dropping (previous best 15) coming back cold running amps 4.9 and sweating
cabin at 78 deg's c -best seen in 18 months 85 !!

ful;l charge remember

every thing looking like undersized cond coil then after running five minutes then it bypasses!!

dropped refrigerant charge to 500 gms run system with no water as we now feel that the water -whilst helping the condenser reject heat- isn't the compressor problem

suct 50
disch 275

runs approx 1 hour -never bypassed once...!!

how can this be??


come on guys

two indentical systems doing the exact same thing??

answers please

cheers

richard

[frank]

if we fully charge the systems as man's plate = 650 gms

Hi Richard

If the systems run better with a lesser charge then it makes sense that the plate charge relates to lower ambient conditions. Is the equipment designed for lower ambient areas?

runs 10 minutes(ish) then bypasses suction rises and disch falls...running amps drops to 2.2

A classic symptom of the compressor not pumping to full efficiency

[Jase]

Hi Richard

As Frank has stated it is possible that the equipment is not rated for higher ambient operation. I used to manufacture a/c systems for offshore (EXD) stuff. Mostly the kit that was being produced was usually destined for north sea area as requested by the clients but sometimes the cabins these a/c units were installed in were shipped all over the world. As you can imagine, when these a/c units were subjected to higher ambients the more problems occurred. Basically you ended up having to increase condenser size, indoor fan etc but hopefully you won't have to go down that road

Regards

Jase

[rbartlett]

hi guy's

I have a hunch that it's the refrigeration charge which is causing he problem. As mentioned at 500 grams not probelm with the equalisation but adding to 650 -as per spec- we get the problem. -almost instant after several hours of 500gms working okay.

therefore I can only assume that liq is entering the compressor -although they have accumulators- and either washing the oil film or just plain lifting the vane

this is where you lot can come in

i have tried to speak to la unite hermatique but they are on holiday till the end of the month -i even rang luh in the uk and they have august off too

is there anyone here who can either confirm or point me to a paper which lists the actual effects of liq entering a rotary comp?

I have a meet early this week with the company and i need answers fast!!

cheers

richard

[rbartlett]

still waiting for some further info but thought i's post some pic's

cheers

richard

[chilly]

Hello Richard,
I didnt realize you were already out there.

I would sugest the following as I believe you may have a design problem.
Also your com[pressor problem may be bypassing because it has overstrained and the bypass is now damages and passing sporadicaly, Or you may have the bypass acting correctly but the initial problem is still staraining the system, Either way the way forward tis to check initial design.
Can you supply room size and equipment inside room so we can calculate the load, Also what temperatures air on, air off and evap, + ambiant , air on cond , air off cond, condencer in / out.

Manufacturer and model of cond and evap, Tev type and size, + orifice size if this type of expansion devise is used.

[chilly]

Sorry Also can you supply temperature and pressure of both Liquid line before expansion valve and suction line please so we can deduse refrigerant state.

[rbartlett]

sadly not only have I been but I'm back!

regarding the bypassing -both systems were identical and both acted exactly the same regarding the charge ect.

however because we were told one was operating correctly and one had a gas leak we did not take any data logging equipment as we relied on the weigh method for charging.

cheers

richard