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hookster
10-05-2008, 12:15 PM
Hello All
I have a client that is addamant that his cold store evaporators do not require a regular cleaning (I have atated a minimum yearly with twice yearly recommended)
The evaporator coils are very dirty as enviroment is dirty and majority of product is cardboard packaged.
Stores vary between 14 and 4 DegC holding temp.
I would like some information on efficiency reduction and if possible a way of determining the reduction in efficiency of the evaporators due to build up.
What is recommended cleaning?

Grizzly
10-05-2008, 01:44 PM
Hello All
I have a client that is addamant that his cold store evaporators do not require a regular cleaning (I have atated a minimum yearly with twice yearly recommended)
The evaporator coils are very dirty as enviroment is dirty and majority of product is cardboard packaged.
Stores vary between 14 and 4 DegC holding temp.
I would like some information on efficiency reduction and if possible a way of determining the reduction in efficiency of the evaporators due to build up.
What is recommended cleaning?

Sorry hookster.
I am with the client on this one!
Grizzly

US Iceman
10-05-2008, 05:55 PM
And I'm going to take the opposite approach Grizzly. I have seen a lot of coils coated in dirty cardboard dust that once wetted turns into mud.

Twice a year cleaning is a little extreme, once a year is questionable, but once every five years or so I think is reasonable. But then, it depends on the rate of accumulation too.

I've seen coils that had never been cleaned, but once every five years or so should be acceptable as part of preventive maintenance. If they were put on a rotating schedule the coils could be cleaned one at a time over the span of a year.

The only way I know how to estimate the difference is to look at the suction pressure currently running and what it should be.

monkey spanners
10-05-2008, 06:15 PM
One of our clients runs an agg packing wharehouse and thier maintenanace staff would wash out the evaporators every few months due to the cardboard dust in the air.
And another customer who made pre packed sandwitches used to have us clean the evaporators once or twice a year due to dust from those blue paper towels blocking the evaporator.

I think they would be a bit like condensers in that it would be easier to keep them clean than clean one once its become blocked with cr*p. On a cellar cooler once we had to remove the evaporator outside so that we could pressure was all the black mouldy stuff out of it, would have been cheaper to keep it clean in the first place.

Jon

Grizzly
10-05-2008, 07:49 PM
And I'm going to take the opposite approach Grizzly. I have seen a lot of coils coated in dirty cardboard dust that once wetted turns into mud.

Twice a year cleaning is a little extreme, once a year is questionable, but once every five years or so I think is reasonable. But then, it depends on the rate of accumulation too.

I've seen coils that had never been cleaned, but once every five years or so should be acceptable as part of preventive maintenance. If they were put on a rotating schedule the coils could be cleaned one at a time over the span of a year.

The only way I know how to estimate the difference is to look at the suction pressure currently running and what it should be.


Please read the post again

"I have a client that is addamant that his cold store evaporators do not require a regular cleaning (I have atated a minimum yearly with twice yearly recommended)"

Even your statement could not be construed as regular cleaning.
I also have many years Cold store experiance and agree that in unusual circumstances more regular cleaning is required.
And I totally agree with both you and taz.
But I still disagree that in normal circumstances twice a year is the required frequency.
Maybe I did not clarify what I ment.
Basically I agree with your statement but don't read into mine what was never there in the first place.
Grizzly
Ps Your turn to rant now mate!

monkey spanners
10-05-2008, 08:29 PM
I suppose the question i should have asked is "Is the coil in a dirty environment and gets blocked quickly?"

As Grizzly points out many evaporators in clean environments run for many years without needing cleaning.

Jon

philfridge
10-05-2008, 09:21 PM
I would sugest they just be cleaned as required when the condensers are cleaned just have a butchers and show the customer when the crap has built up.

US Iceman
11-05-2008, 02:19 AM
Ohh Grizzly why do you have to be so much trouble?:D

I took the comment from the original post as never needs cleaning. So I might have read more into than I thought on the first pass. My bad.

We agree now.

And yes, anything more than every five years or so is excessive (unless the atmosphere is filthy).

Billy Ray
11-05-2008, 09:11 AM
surely the coil / drip pan etc requires cleaning yearly with a suitable solution for the following possible reasons -

legionella
listeria
salmonella
any other growths!!

the potenial risk is low, but should be taken into consideration?

Billy Ray

hookster
11-05-2008, 11:25 AM
Thanks All
Your replies are interesting but these are very large coldstores operating with fork lift trucks (gas & electric) the evaporators are very dirty at present with pull down temperatures taking a lot longer.
A dirty evaporator will have its heat transfer coefficient reduced. Can this be measured? Before critical level is reached where air flow reduction is noted.
An annual cleaning that I have suggested is for an assesment thereby a preventitive maintenance and planned maintenance can reduce the reactive maintenance.
With an innitial annual inspection your suggested five year shedule can be factored as an achievable goal for the client.

hookster
11-05-2008, 11:30 AM
Billy Ray
Your response is in the track that I am taking as the majority of product is fruit. There is a noted increase in fruit degradation due to mould/spores etc
The trays are suffering with blocked drain lines due to growth build up.

US Iceman
11-05-2008, 06:14 PM
...the evaporators are very dirty at present with pull down temperatures taking a lot longer.


Have you investigated other possible factors? Or, are you attributing the capacity problem only to the dirty coils?

One other area to look at is the fans themselves. If a centrifugal fan is being used I have seen the blades of the fan wheel accumulate a lot of dirt also. This drastically reduces the discharge air volume of the fans, and hence the coil capacity decreases.

If this is an old cold store the coils may be flooded ammonia and oil has accumulated in the coils.

If the coils are DX the TXV's may have been closed down to reduce liquid carryover caused by worn valve pins and carriers.

More thing scan be discussed if the system is one of the *****s.

There are a lot of issues, but lack of pull down capacity is a big topic which I'm not sure we could attribute it all to dirty coils.

kevbrowning
22-07-2008, 04:04 PM
Hi guys,

Our evaporators coils were clogged up and we got a company in called (JMP Industrial Cleaning Services)
to clean our units, they specialize in cleaning coldstores and evaporators,afterwards our evaporators worked alot better and we saved about 10% on our yearly electricity costs, so we now get them cleaned on a yearly basis as a precaution. There are not many companies around that specialize in this type of cleaning but if you need your equipment cleaning then i couldnt speak more highly of them.


jmpcleaningservices . co . uk