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View Full Version : Crankcase Heaters that don't stay put!







Grizzly
03-11-2016, 10:28 PM
Hi Guys.
Attached is a photo of a modern type of external c/case heater which several manufacturers use around the base of Scroll comps within their Chillers.
As you can see yet again I have come across ones that have fallen off the base of the comp.
And now resting on the base plate doing diddly squat!
What ever happened to the flexible braided ones that stayed put?
Still available but more expensive I suppose?

14413

Cheers Grizzly

cadwaladr
04-11-2016, 03:43 AM
It must be cost,although a little stupid as warranty claims on the compressor will increase everything is being cut to the bone because of the Chinese dumping,only my opinion of course I love Chinese food but not their engineering expertise

Magoo
04-11-2016, 03:57 AM
Most likely a Friday afternoon set up by numb nut on assembly line, they have a hose clip type screw it up tight type thing.

Grizzly
04-11-2016, 07:11 AM
I suspect the heaters may be Chinese manufacture!
But the Chillers that I have seen so far are ether Italian or American Manufacturers.

If you note these heaters have a band of fingers on them.

I can only assume that the fingers grip around the comp body?
They are spring loaded and over time seem to loose their tension.
I.E. Fall off!
Does anyone think it matters which way up they are fitted?

I spoke to one manufacturers engineer and they recommended changing them for the Braided design!
Grizzly

cadwaladr
04-11-2016, 07:36 AM
If they put lugs on the body at manufacturing then they would not slip down,plus it would help the numpties realise where they should be located!

cadwaladr
04-11-2016, 07:45 AM
I got called in to a site years ago to two r750 prestcold that failed annually only to find that the crankcase heaters had never been connected,by Christ they were heavy to replace and they ran trouble free for years after my visit ,the customer was well chuffed and service contrac to boot!

AlexG
04-11-2016, 09:00 AM
I also came across this problem with Copeland scrolls. Aluminum tape helps.
Cheers

Grizzly
04-11-2016, 05:25 PM
Hi Alex.
You are correct there, these are usually Copeland Scrolls that have this type of heater fitted!
Grizzly

Brian_UK
04-11-2016, 08:16 PM
The little fingers are are to spread the heat.

If they aren't fitted above the bottom dome of the compressor then you're they will keep falling off. A parallel surface is needed to tighten onto.

Rubberised stick better.

Grizzly
04-11-2016, 11:14 PM
I Continue to learn.
Thanks Brian.
The ones I have seen do appear to have originally been mounted on the parallel sides.
They just don't stay put.
Grizzly

Brian_UK
04-11-2016, 11:21 PM
I wonder whether some high temperature silicone blobbed onto it might hold them steady.

Grizzly
05-11-2016, 08:27 AM
Not a bad idea Brian.
Alex's option is good also!
Basic but that's the best sometimes.
No-one is admitting yet how big a problem this is!
Or it might just be me?

The problem as I see it, is that when the c/case heater is attached and on.

The heat it produces is dissipated though the metal it is in contact with. Once it falls off it will eventually overheat and Fail!
As we know modern designs have scroll comps underneath large condensers. In many instances there is no non return valve in between the condenser and the head of the comp.
Yes the internal non return within the scroll has been improved over the years but look at the size of the discharge manifolds to them!

A crankcase heater helps ensure that no condensed liquid is present at start-up.
Which is fundamental at low ambient temps especially during the early hours during winter.

Anyone ever witnessed low oil cut or lp cut outs! Only to analyse the Chiller History and realise that the comp only ran for seconds or a few minutes.
A lot of faults are identified as the problem with modern software, when really it was due to little or no lift across the comp on start -up.
Simply put "On start-up the comp was too cold!"

Thanks Grizzly

Rob White
05-11-2016, 10:26 AM
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Drill some holes in the compressor and use selftapping screws to hold them on

:D


Rob
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Only kidding :D

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monkey spanners
05-11-2016, 12:54 PM
The genuine Copeland ones are like a big jubilee clip, i've not seen one come loose yet. The only problem i have seen is if the heating part of the band goes over the welded seam on the compressor as part of the heater is then not touching the body of the compressor and have had a few burn out due to this, you can see the stainless has gone yellow due to heat.
The newer style Copeland ones are similar but are aluminium and not stainless, not had any problems with them so far.

Maybe the problem ones are pattern parts?

Grizzly
05-11-2016, 02:29 PM
Rob.
A Trainer with a sense of Humour such as yourself, is like a breath of fresh air!
Hi MS.
Not dissing Copeland (Other Makes do exist!) in any way, Just that there comps are fitted to lots of Chillers and some have the ones that I am talking about.
Most use the Jubilee clip style of tensioning.
Grizzly