Strange set up

[chilliwilly]

Evening all

Went to a newly opened farm shop near Bradford that a customer of mine reccomended me to on the way home, wish I hadn't have bothered. He's bought a walkin cooler/fridge off ebay from a pizza take away down in Essex that went out of business within the first 12 months. Its a Scandia unit, less than 2 years old, and its not holding temp, it cools down to it’s set point of 3 deg C when he first turns it on, then the walkin it starts gaining temp. He told me when he bought it last November, it pulled down to temp within the time it took to make and drink a potta.

The pot is pumping its bollocks off, condenser coil airways are blind with sh!te, evaporator icing badly (which looks home made not factory), and the condensor unit and fan is horizontal? How that's suppose to work I don’t know, it looks a proper Mickey mouse unit although the pipe work is quite professional. At first I noticed that the evaporator fan was running on the slow side and maybe causing the coil to ice up, he told me it was catching so he fiddled with it to stop the noise. Anyway I ended up changing the motor (10w for 16" fan?) for a new 25w, and the icing up seem to get worse, with no reduction in temperature. Don't you just hate that when that happens?

After attempting to connect the guages with no success due to no high side schrader, and not being able to back or front seat the rusty service valve on the pot. I came to the conclusion that it could be overcharged, and or the capillaries are blocked, (2 in total feeding 2 rows), they also seem a bit on the short side too. Checked for leaks and non found. So I've told him that the usual meggering, degassing, vacking, new drier, new service and schrader valves, pressure testing, and regassing needs doing before it will start to cool again, that’s if it ever did in the first place. I don’t think he was convinced though, so I told him to have a think about it and feel free to get a second opinion from someone else and let me know the outcome. I just don't want to be the one to tell him that he's been ripped off and the system may need to be modified for it to work properly. Especially when he didn't seem convinced.

Its just that I've never seen a condensor and fan oriented in the horizontal position, how on earth can it work efficiently and for the gas to condense and run down the coils to the receiver? Which in turn seems to be mounted horizontally in the same orientation of the coil, but the lowest point is only 4 rows deep, but at the opposite end to the high side feed to the condensor? Also my thoughts and instincts tell me it should be a XV and not a cap feeding the evaporator.

The charge is only about 1.5 kg stamped on the decal, but I've known that amount to be metered with an XV, and it seems strange with the cooling load being variable that its cap fed. The walkin is about 3m*2m*2.5m, but not enough information about the system regarding power and pot size. I also noticed a lead with connectors taped up marked up door switch, but no evidence of one being fit on the door. There's a hot gas defrost, which I couldn't get to, to check due to the condensor unit being fit back to back with the evaporator, and less than a foot of working space between the condensor unit and the wall of the room where its sited.

I just wish that I had a couple of line taps with me just to see if the high side was abnormally high, and the low side almost in vacuum. My camera on my phone doesn't work so sorry no pics. I'm not that bothered about going back to it to be honest, but I know that it will bother me for months to come if I don't, and whether or not my instincts were correct. And I just wondered if anyone else has had a similiar experience with a system like this?

[mikeref]

Chilli. Similar experience with second hand equipment? All the time!! If there is no reciever, than it has to be capillary feed. Dual capillaries feed saves running one longer one with only one point of entry to evap. High heat and humidity will freeze evap quickly. Maybe unit was fitted to old room and unit cannot deal with poor insulation, or this setup never worked properly to begin with. Changing evaporator fan motor might have increased air flow, as old motor may have been struggling to keep up speed. 10 watt for 16 inch blade is too small. You didn't mention anything on superheat but when evap ices up and frost is present on suction line, than capillary and gas charge will be o.k. Hot gas defrost on this?.. mike.

[monkey spanners]

Sounds a bit like those zanotti units that hook over the wall, some of those units have 2 pole evap fans that run at 2900rpm instead of 1200 that normal 18w motors do.
Did you manage to clean the condenser?
Seen a few of these style units leak on the hot gas solenoid.
Is the temp probe ok? May be cooling but display says not.

Jon :)

[NoNickName]

Horizontal condensers are commonly found on General Electric 2-doors fridge-freezers. As long as the liquid pipe is on the lowest row, you're fine.

[Tayters]

Not common practice to have a reciever with a cap tube. They rely on the changing subcooling and pressure difference across the cap tube to alter the flash point so with a reciever this wont happen as no refrigerant to back up into the condenser.
Sure some places have them and stuff seems to cool but that's not how they are designed to work. There is one on a freezer our firm looks after. I've charged it to a subcooling of 10K and still the evap was starved. Sight glass looked about half full but it kind of worked - just took ages to pull down (original condensing unit was replaced with this one yonks ago). Other folks have worked on it and charged to a full sight glass and the thing doesn't want to know. Crazy times.

Good luck with that one, turd polish required.

Andy.

[al]

when he "adjusted" the fan to stop it making noise, is it possible he flattened the blades? Fit a smaller motor and maybe change the blade, check the evaporator is clean. Also as noted by MS it may be a mono bloc converted to a remote, hence the weird condenser arrangement, if the room is constructed poorly it will never cool properly.

Did you take any pics?

Alec

[chilliwilly]

I think I'll trust my instincts and let him contact somebody else for a second opinion, because I honestly believe that it has never worked in the first place. As it came out of a pizza take away, that went out of business in the first year and left an unpaid gas bill of £35000.00 amongst other things, and the new owner said it was minging inside it when he went to view it. May suggest that the unit wasn't working in the first place, and the previous owners wouldn't have cared if it wasn't holding temperature even if they had of noticed it. I think the fact that it pulls down when it first gets turned on and then doesn't hold temp, and then only averages about 7-12 deg after a while, shows that it should have an XV and not a cap as its a variable load. It has got a pressure control switch and a standard controller with display and defrost, and the pot is probably shutting off with the klixon because it’s overheating and could have prematurely worn the pistons causing inefficiency.

The receiver is only very small, that's if it is a receiver and not a small manifold at what is normally the bottom take off point at the condenser, unlike the 1 litre size or larger you would expect to find on an XV metered unit. From what I can read on the decal, its designed to hold 1.5 kg of 404a, but with the very dirty condensing coil oriented in the horizontal position, and about 2 foot lower the evap coil with less than a meter of pipework, and only what seems to be a very small receiver about an inch in diameter and 6 inch long. The icing up on the lower part of the coil could mean its over charged and flooding the evap coil, if it contains the designed charge. If there was enough room to actually get in and fit a couple of line taps and see if the low side is low and the high side is very high, then this would prove my thoughts. But then again if decanting some charge out of it steadies up the pressures, I've still got the problem of wondering how a strange set up like this is actually suppose to work properly. So I think I'll stick with my instincts and stick with a second opinion, because I know it will be a nightmare to fix with and I hate recalls. I'm just glad there's a forum like this for situations and multi dilemmas when you don't know what to do for the best. Thanks for all the replies though lads.