Storage Heater Elements. How long do they last ? Any Electricians... - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 11th February 2010, 06:19 PM   #1
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Default Storage Heater Elements. How long do they last ? Any Electricians...

If you look at the picture, would you believe the element that has failed is the one on the left.
That twisted burnt element at the right still functions unbelieveably and reads just under 70 ohms approx which is about correct.

We have four storage heaters, and this one has had an element fail for the second time... and that mangled thing... well that makes it three failures. The heater is only around 5 years old... first failure after just 15 months or so. The other 3 are Dimplex, this one is Alto brand but is identical internally to the Dimplex.
Before I pulled it apart I decided to replace all 4 elements... good job too looking at this.

So question... how long do these things normally last ? The oldest Dimplex with these 850 watt elements is over 12 years old and going strong. The heater doesn't overheat... they just seem to fail for some reason.
Attached Images
File Type: jpg IMAG0169.JPG (385.5 KB, 54 views)
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 12th February 2010, 11:31 PM   #2
star882 is offline star882  United States
diyAudio Member
 
star882's Avatar
 
Join Date: Mar 2007
It looks like the heater uses analog controls, which put the elements through a lot of thermal stress cycles.

Maybe it's possible to retrofit it to digital control, using a SSR to switch power. The SSR can be cycled very quickly (one cycle on, one cycle off for 50% power) or even phase angle controlled. The microcontroller can be programmed to ramp the power up and down to minimize thermal stress.

If only 50% heat output is needed most of the time, a very simple solution is to add a rectifier in series, bypassing it only if full heat output is needed. In fact, that trick is frequently used in appliances. I read a story about how someone kept having to replace the elements in his water heater because of hard water. He installed a rectifier (of proper ratings in a proper enclosure) in series with the water heater and he never had to replace another element.
__________________
"Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!
  Reply With Quote
Old 12th February 2010, 11:57 PM   #3
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
Hi
How does it fail.
My experience with elec stoves is the connector or socket goes first mostly,,, maybe should repace both element and socket as a pair. ie Once one side conn is damaged it causes the other side to go sooner than later.
The connector system really takes a beating with movement from thermal cycling.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust

Last edited by infinia; 13th February 2010 at 12:13 AM.
  Reply With Quote
Old 13th February 2010, 06:24 AM   #4
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by star882 View Post
It looks like the heater uses analog controls, which put the elements through a lot of thermal stress cycles.

Maybe it's possible to retrofit it to digital control, using a SSR to switch power. The SSR can be cycled very quickly (one cycle on, one cycle off for 50% power) or even phase angle controlled. The microcontroller can be programmed to ramp the power up and down to minimize thermal stress.

If only 50% heat output is needed most of the time, a very simple solution is to add a rectifier in series, bypassing it only if full heat output is needed. In fact, that trick is frequently used in appliances. I read a story about how someone kept having to replace the elements in his water heater because of hard water. He installed a rectifier (of proper ratings in a proper enclosure) in series with the water heater and he never had to replace another element.
Interesting idea using SSR. Yes these are very much analog Actually this heater uses a hydrostatic stat that has a capillary tube on top of the core case.
The old thermostats (bimetal) cycle on/off pretty quickly I notice, and these don't... perhaps being off for 40 minutes then on for 20 or 30
Wondered whether the calibration is out.

I agree, solid state control would be excellent.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 13th February 2010, 06:29 AM   #5
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by infinia View Post
Hi
How does it fail.
My experience with elec stoves is the connector or socket goes first mostly,,, maybe should repace both element and socket as a pair. ie Once one side conn is damaged it causes the other side to go sooner than later.
The connector system really takes a beating with movement from thermal cycling.
It just fails by noticing that it's either cooler at one side, or by noticing the side away from the sensor is red hot (as the sensor side doesn't reach it's temp fully to cut off the stat).
However all the elements have definite signs of overheating... the metal dissintegrating. There was a pile of fine dust (metal) at the base of each.
The connectors fortunately are extremely high quality and obviously designed for the heat stress involved... they all appear as new still.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
how to wire 6.3VDC heater on a heater with center tap (12.6V series, 6.3V parallel)? jarthel Tubes / Valves 9 14th April 2012 05:36 PM
Regulated Heater on the 6SN7 Aikido Plate to Heater question john65b Tubes / Valves 6 24th November 2009 05:44 AM
Passive X-over elements available in Australia Cloth Ears Multi-Way 10 5th May 2006 07:30 AM
Focal elements Space489 Multi-Way 0 22nd December 2004 12:17 PM


New To Site? Need Help?

All times are GMT. The time now is 08:05 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2