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Old 11-07-2018, 06:38 PM   #1
Kiltym
 
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Default Replacing relay

I am attempting to remove the Kiss relay from our Westy.

Issue I am having is accessing the screws so I can remove the nylocks that mount the relay onto the metal mounting surface.

I have removed one nut in the rear lower corner that holds the metal mounting surface to the wall, removed the fan housing, which then allowed access to two screws on the back wall. This allows me to move the metal frame, with the converters and relay. However, I still cannot pull it far enough from the wall to access the screws. The converters are bumping against the back of the water heater.

I sincerely hope I do not need to remove the hot water heater to access these screws.....

Anyone have any hints?

Thanks!
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Old 11-07-2018, 11:04 PM   #2
Robert Foster
 
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Default Re: Replacing relay

It's been a few years since I removed mine, so I cannot remember the entire process, but I can confirm that I did not have to remove the water heater or any other parts to remove the relay.
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Old 11-08-2018, 02:46 AM   #3
Adolphus
 
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Default Re: Replacing relay

I removed mine without touching the 4gal water heater by removal of the entire metal frame with intact relay and converters. You may want to do this which will make the relay much more accessible.
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Old 11-08-2018, 04:30 AM   #4
Kiltym
 
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Default Re: Replacing relay

Thanks for the replies. I managed to get the nylocks off by pressing at a hard angle to keep the screw from turning while turning the nylock. Was able to remove without removing the metal mount and convertors, but would be easier to access the screws.

When I reinstall, I will use normal nuts and lock washers which will allow for much easier removal in the future since I can get a finger on the head of the screw, but cannot hold it secure when trying to remove the nylocks.
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Old 11-08-2018, 05:39 PM   #5
onemanvan
 
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Default Re: Replacing relay

The kissling relay is problematic... As with any relay the contacts can eventually get coated with carbon and lose their ability to pass sufficient current to satisfy the load. In the case of the Kerstner we are talking VERY high current - upwards of 100 amps! The Kissling relay is magnetically latched - it is my belief that the engineers intended for it to be mounted horizontally. I believe Westfalia/Airstream made a mistake when they mounted it vertically. There is only a weak magnetic force holding the contacts in a closed position when the alternator is supplying the load. To make matters worse gravity is working against the weak magnetic force in this mode of operation. Therefore - when the vehicle is bouncing along down the highway the relay contacts chatter. As the contacts "make and break" carbon builds up on them. As a byproduct of this chattering EMF spikes are sent back to the alternator causing premature failure of the diodes that rectify the supply current. Read that as alternator is destroyed! I replaced mine with a manual battery switch.
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Old 11-08-2018, 06:25 PM   #6
Kiltym
 
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Default Re: Replacing relay

Maybe I will mount the replacement horizontally based on this theory. Too bad they are not servicible as bit of contact cleaner inside might bring one back to life.

A switch is certainly one approach, but having wired our dc-dc charger to the relay, replacing it with a switch defeats the automatic function of the relay. There are a few replacement relays available that can be used instead of the Kiss.
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Old 11-08-2018, 08:35 PM   #7
onemanvan
 
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Default Re: Replacing relay

It's been 8 years since I yanked out the Kissling relay and replaced it with a battery switch, so the details are not fresh in my mind. I do remember tapping lightly on the Kissling relay with the handle of a screwdriver when it was in the magnetically latched position and observing an erratic voltage reading on the output terminal[s]. That's when I researched the spec's on the relay and realized it was magnetically latched - which explains the high cost - $300 ???

The main advantage of a magnetically latched relay is it consumes less power to keep it latched. But since there is an abundance of power available from the alternator that seems like overkill.

A less expensive SPDT relay/solenoid/contactor might be OK - provided the continuous current rating is sufficiently high - IE: preferably 200 amps... However the relay coil will generate 13 watts of heat continuously when energized- so the max heat rating of 150F could be exceeded - which may explain why the OEM relay is magnetically latched?

200 amp contactor: https://www.alliedelec.com/white-rod...-911/70101972/
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Old 11-08-2018, 08:44 PM   #8
Kiltym
 
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Default Re: Replacing relay

Yes, this is another one as well that I believe would work OK: https://www.colemanair.us/vp_asp/scr...exd.asp?id=718

Specs: https://www.ametekswitch.com/product...e-solenoid-sbd

The company above lists it incorrectly as DPST, according to Ametek, it is SPDT which is what is needed.

Last edited by Kiltym; 11-08-2018 at 09:29 PM.
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Old 11-09-2018, 12:46 AM   #9
onemanvan
 
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Default Re: Replacing relay

Correction to my previous statement:

I thought I remembered researching the specs of the Kissling relay and discovering it was magnetically latched.

I just went back and double checked the specs and realized it's NOT magnetically latched.

Coil power consumption is 10 watts.

Kissling 29.221.11 : https://www.peerlesselectronics.com/29-221-11-relay

https://www.kissling.de/fileadmin/pr...00A_Relais.pdf

They do make a magnetically latched bistable relay but the p/n is 30-221-11

https://www.kissling.de/fileadmin/pr...s_Prospekt.pdf

Since ours is NOT magnetically latched my theory suggesting the contacts are 'chattering' in a vertical orientation due to a weak permanent magnetic field couldn't be true.

However - the electromagnetic field of the coil still has to overcome gravity pulling on the weight of the internal contacts compounded by road vibration, etc... when the relay is mounted vertically...
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Old 11-10-2018, 01:01 AM   #10
CaptnALinTiverton
 
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Default Re: Replacing relay

Quote:
Originally Posted by Kiltym View Post
Maybe I will mount the replacement horizontally based on this theory. Too bad they are not servicible as bit of contact cleaner inside might bring one back to life.

A switch is certainly one approach, but having wired our dc-dc charger to the relay, replacing it with a switch defeats the automatic function of the relay. There are a few replacement relays available that can be used instead of the Kiss.
You have to read the specs carefully. Most of these high power relays are required to be mounted vertically as specified by the manufacturer.


AL
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