sport 9 - white paste underside tco when remove

Issue = no H/W; flowLEDoff; ~13.4ohms on 2 back Neutral posts to each of 2 front posts of tank. (Assume this OK?)



(1) How test 2 microswitches (872.01,28) ?



(2) Or how test flow and switch assemblies (1563.507,509) ?



(3) Continuity on installed TCO gives none. Take TCO off and now says ok!

Being confused I look top of tank where TCO sits and 3/4mm dia blob of white grainy paste. I thought thermal conductive paste (like on PC cpu to heatsink). Then notice on underside of TCO the disc pushes into TCO body. Pushed in and loose continuity and at rest gain continuity. I surmise that paste is some sort of buildup? I'll just clean TCO and tank top and reassemble.



(4) But... HOW does heat from tank top cause this disc to move upwards into TCO causing loss of continuity/power cut off?

I was expecting sort of bi-metallic sort of heat sensing setup...



Think need your comments.



Thanks in advance.

Tim



PS. Greeeate site and loads of food for thought - you people really make your biz the place to buy goodies... :)

Asked 12 years ago by Anonymous

Issue = no H/W;flowLEDoff; ~13.4ohms on 2 back Neutral posts to each of 2 front posts of tank.(Assume this OK?)

Sounds OK

How test 2 microswitches(872.01,28) ?

 

Check for continuity, push button in continuity let button gono continuity

 

Or how test flow

Rough check turn flow up and downthe flow should modulate.

and switch assemblies(1563.507,509) ?

See 1 Above

(3) Continuity oninstalled TCO gives none.

= TCO faulty

Take TCO off and now saysok!

Can’t explain that! Unless it has something to do withthe “paste”

Being confused I look topof tank where TCO sits and 3/4mm dia blob of white grainy paste. I thoughtthermal conductive paste (like on PC cpu to heatsink).

No thermal transfer paste used onthis unit, more likely to be residual flux that wasn’t cleaned away.

Then notice on undersideof TCO the disc pushes into TCO body.

This is correct

Pushed in and loosecontinuity and at rest gain continuity.

Pushing the bi-metallic disc inis the best way to damage a TCO!

 I surmise that paste is some sort of buildup?I'll just clean TCO and tank top and reassemble.

Definitely worth a try

(4) But... HOW does heatfrom tank top cause this disc to move upwards into TCO causing loss ofcontinuity/power cut off?

I was expecting sort of bi-metallic sort of heat sensing setup...

The Disc is Bi-metallic

Answered 12 years ago by The Shower Doctor

Thanks 'Doc' :)

Your time taken to answer 'all' OP points is greatly appreciated and a rare quality!



I did not clearly say that the white paste looked like the corrosion one sees on car battery cable/post mounts and even the metal tray holding battery (oops this must show my vintage;)



The grainy paste buildup I believe was a reaction between TCO metal and ?copper/brass tank top.

The build up forced TCO 'disc' up which cut the circuit. Once thoroughly cleaned and a smear of petroleum jelly put on disc and tank top, I just reassembled and hey presto! Instant hot water returns...

Let's see how long it lasts - if not I'll certainly order TCO from showerdoc.com



I could not have done this job without the video and 'The Doc' answers to similar issues. Being able to read them all gave one some familiarity/confidence with the unit and allowed me to tackle it.



An aside: one MUST be careful regards what one unassembles and that exactly same reverse reassembly is done! Water/elec do not mix!!!



Thank you very much 'Doc'

Answered 12 years ago by Anonymous

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