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View Full Version : Storage space design - does a modification contravene BS EN 378?







chilliwilly
23-07-2017, 11:39 PM
I have been to several sites over the past few months where they have complained of units not holding temperature because they have left the doors open on cabinets and walkins, because they think they can use it like an aircon unit to cool down their working area.

After asking staff on site if they're leaving the doors open and them saying no, I have ended up changing fans and controllers, increasing defrosts cycles only to find that the evaporators still freeze up.

On visiting a site for a third time, I noticed that the doors were in fact being left open as I first suspected, I contacted the site managers and let them know of my findings and to inform the staff of the necessity of keeping the fridge doors closed. Except when taking things out, cleaning and stock taking, where they should be switched off. And also that the previous calls are not re calls and are chargeable due to the way that they have been using the fridges and not being honest about leaving doors open.

Over the following weeks the problems were still the same, the units weren't holding temperature, because the evaporator coils were freezing. So I bypassed the door switches on the cabinets, and wired timers into the the walkins controls, so if the doors are open for longer than a minute, the compressor shuts off.

The calls that I'm getting now are exactly the same, the units aren't holding temperature so they had turned them off. I returned to two of the sites and there was nothing wrong with the units, they started to pull down as soon as I switched them on, and they held temperature with no further problems.

Then I got an email from the sites facilities contractor informing that they had received a complaint about the way the refrigeration units were not being looked after, and stating that I had broke the law by allowing the fans to run whilst the fridge doors were open.

They went on to say that the units were not designed to operate this way, and I had ho right whatsoever to modify the design. And by doing so adding an unnecessary heat load to the cabinet causing a non compliance with TEWI, and they were going to inform REFCOM of my actions!

I thought about this and then realised that they had misconstrued the TEWI regs, and what I had actually done was no different from what an aircon unit does when a door or window is opened causing an extra heat load to the system.

I emailed them back and informed them of my reasons of bypassing the door switches, and in doing so I was actually reducing the TEWI by making sure that the fridge doors are always kept shut when access to the fridges are not required. And in fact it was no different to an aircon unit. I also informed them that their annual leak check and service must be well overdue, and that I wanted to see records of past leak checks and services to make sure they were doing their bit and complying with TEWI.

I haven't had a response from them and I have heard nothing from REFCOM, I don't think that I will. It amazes me though when other trades poke their nose into things they do not fully understand, and try tell you that you don't know your job, and then try cause trouble for you.

monkey spanners
24-07-2017, 06:06 PM
Sounds like the employees got the hump with being reported and tried **** stiring to me. I'd look into fitting some data loggers to see whats going on when you are not there.

Maybe wire the door switch to the solenoid valve, would pump down soon as door opened then a time delay for restarting.

Years ago we had one where someone was turning the compressor off overnight, temperatures were always good in the day but meat was spoiling, wired a Tattletale across the isolator and found it blown the next day!

mikeref
25-07-2017, 08:40 AM
Full Evaporator ice up or partial? High or Low Humidity room and do the rooms have Curtains.
EBM Evap fans? If so and they are single Phase, are they running at the correct speed?

Can't comment on your specific question though i believe Monkey Spanners suggestion of a Data Logger will help sort issues.
Just don't let them know you are doing this. Show them the Data after reviewing. No Laws Broken. Hope this helps.

chemi-cool
25-07-2017, 02:45 PM
to avoid any headache from the client, you can install at the refrigerant outlet of the evaporator a KVP to maintain constant evaporator pressure.

chilliwilly
27-07-2017, 12:39 AM
Sounds like the employees got the hump with being reported and tried **** stiring to me. I'd look into fitting some data loggers to see whats going on when you are not there.

Maybe wire the door switch to the solenoid valve, would pump down soon as door opened then a time delay for restarting.


Years ago we had one where someone was turning the compressor off overnight, temperatures were always good in the day but meat was spoiling, wired a Tattletale across the isolator and found it blown the next day!

Yes that's what I meant when I wired it to shut the compressor off. I can't remember if I've ever used a data logger, I probably have but probably for something else.

Which make and model would you recommend?

The walkins are just bungled together economy off the shelf units, low - medium humidity, mainly covered produce and minimum meat, evaporators were fully icing up due to the doors being opened on the hot humid days.

As for connecting an evaporator pressure regulating valve, questions would certainly arise due to cost of the job and my reasons for doing it.

I haven't received any complaints that the units are not holding temperature or any word from REFCOM regarding the matter, maybe its because the weather has been cooler. I'm going to assume that I've solved the problem, or they are using someone else. If all the calls stop including the catering equipment calls, then I'll take it they have shoved me out.

Thank's for the replies.