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#185058 - 03/01/09 11:18 AM Immersion Heaters
clgman Offline
New Member

Registered: 02/24/09
Posts: 2
Loc: Boston, Ma
Gentlemen: This question concerns both application and safety(perhaps more) on direct Immersion Electric Heaters in a sump of a Cooling Tower. The Heaters are in direct contact with the water of the sump (cold water basin) to prevent freezing (typically 40 to 45 degrees). The sump areas are typically large enough to access through a door onto a cat walk. This places a worker directly above a sump area with a potentially charged (heater energized and failing) water source. Finally, my questions!! Is there a Megohm reading that the heater should pass to be considered safe, and does or should any type of code call for a specific type of breaker or fuse(circuit protection)for this application ?? More information available if required, thanks.

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#185059 - 03/01/09 11:40 AM Re: Immersion Heaters [Re: clgman]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
We use immersion heaters everywhere, like spas and domestic water heaters. The case of the element is usually bonded. Generally they seem to be pretty safe. If you are concerned, put it on a GFCI.
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Greg Fretwell

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#185060 - 03/01/09 12:24 PM Re: Immersion Heaters [Re: clgman]
kohli Offline
New Member

Registered: 03/10/08
Posts: 9
Loc: Ohlo Putnam Co
You are talking about in cooling towers Just put your lock on the heater disconect if you are concerned & why are you in there to do what?

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#185078 - 03/01/09 07:23 PM Re: Immersion Heaters [Re: kohli]
frenchelectrican Offline

Member

Registered: 02/06/03
Posts: 938
Loc: Wi/ Paris France { France for ...
IIRC the cooling towers do have specal safety producres if you used the immerison heaters and yes you must have a disconnection switch if you go in the " restricted " area.

If this on 3 you can get this on GFI relay or GFI breaker it will sense any bad elements that shorting out it will trip the GFI and the alarm luminaire go on to give you a head up the heater malfuction.

Merci,Marc
_________________________
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#185169 - 03/04/09 07:55 PM Re: Immersion Heaters [Re: clgman]
KJay Offline
Member

Registered: 11/27/07
Posts: 763
Loc: MA, USA
Originally Posted By: clgman
Gentlemen: This question concerns both application and safety(perhaps more) on direct Immersion Electric Heaters in a sump of a Cooling Tower. The Heaters are in direct contact with the water of the sump (cold water basin) to prevent freezing (typically 40 to 45 degrees). The sump areas are typically large enough to access through a door onto a cat walk. This places a worker directly above a sump area with a potentially charged (heater energized and failing) water source. Finally, my questions!! Is there a Megohm reading that the heater should pass to be considered safe, and does or should any type of code call for a specific type of breaker or fuse(circuit protection)for this application ?? More information available if required, thanks.


I think that qualified persons following a written safety procedure can do more to prevent accidents than anything else.

IMO, since you normally can't enter a cooling tower to do any maintenance without first shutting down the water pumps at the chiller location, you should also LOTO the circuits or disconnects for the tower heaters and make up water valve before attempting to clean the sump filter grates or perform algae and mold removal.

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#185290 - 03/08/09 10:54 AM Re: Immersion Heaters [Re: KJay]
clgman Offline
New Member

Registered: 02/24/09
Posts: 2
Loc: Boston, Ma
Thanks for the replies, and I understand the normal safety procedures for Lock Out, Tag Out, etc. However to attempt to predict heater failure, or when a heater should be taken out of service before it actual trips a breaker or blows the fuses, a megohmeter reading or hipot test. or some type of test ought to able to be preformed to predict such a failure, and I'm courious about the voltage/current leakage to ground before the fault take place. Thanks Clgman.

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