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Grasslin Towerchron QE2 Controller


Onoff

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Came downstairs this morning to find the place uncomfortably warm. Downstairs CH had been on all night. 

 

The controller seems to be at fault. The LCD display has gone all squiffy and locked. I can press either of the grey buttons and nothing changes:

 

20190226_052158.thumb.jpg.dea772f35f524325d2b5d1b5c7d882aa.jpg

 

Didn't have time to do anything other than whip it off the wall and tape over the connection plate then leave SWMBO a note.

 

Taken it to work with me so I'll whip the cover off and see if there's a replaceable battery in there. Can't honestly remember if I've ever done this before, vague recollections maybe...

 

I'll also chuck a meter on it and see if the relay has failed and is constantly calling on 4:

 

20190226_061519.thumb.jpg.96eb6c9b983986e2475ad57dce5432c6.jpg

 

20181221_084944

 

Still, it's over 20 years old so has done well. Surprised it fails "on" though.

 

This one does downstairs CH and HW. Worst case tonight I swap it out for the same controller above that just does upstairs CH.

 

20181215_083114

 

Was debating renewing with a 3 channel controller maybe, that'll do 2x CH & 1x HW. 

 

Any suggestions on a make?

 

 

Edited by Onoff
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13 minutes ago, PeterW said:

Before consigning it to the grave, you did just try and take it off then put it back on the back plate after 30 seconds. ..? This sometimes clears them. 

 

Yep did try. 

 

Had the back off. Nothing obvious. No idea on the soldered in battery other than it's yellow and has "70" written on it. 

 

20190226_065824.thumb.jpg.1ed4ff7f0fc2034319ebc0d2268aa37f.jpg

 

At rest the pinouts seem correct. 1&2 are NC and 3&4 are NO with respect to L.

 

Relays are obsolete, Omron G6C-2117P-US-SV.

 

Just poked the reset button under the cover and it's come right. Wonder why, never happened before...battery?

 

I'll slap it back on tonight and setup the times again.

 

 

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At ~20 years old the chances are that the 10µF 63 V electrolytic capacitor, between the relays, may have dried out and caused ripple on the supply.  I had this happen on an old time switch about 4 or 5 years ago, and just replacing the capacitor fixed it.  The life of capacitors like this is around 10 years or so, so it's done pretty well to last this long.

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15 minutes ago, JSHarris said:

At ~20 years old the chances are that the 10µF 63 V electrolytic capacitor, between the relays, may have dried out and caused ripple on the supply.  I had this happen on an old time switch about 4 or 5 years ago, and just replacing the capacitor fixed it.  The life of capacitors like this is around 10 years or so, so it's done pretty well to last this long.

 

Will probably have one knocking about. I did think the - end looked a bit odd, like a crack in the factory solder where the lead joins the body:

 

20190226_075915.thumb.jpg.6492a9643eb286fe1fea377bed923fc6.jpg

 

Looking closer I'd say that - and should be soldered to both sides of the board. This side, well it might be making contact with the copper track by there's hardly any flow through:

 

20190226_080528.thumb.jpg.41c8067262914d6a39d98c773c5159ea.jpg

 

Edited by Onoff
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  • 2 weeks later...

Update. The controller was "hanging" more often. Up until tonight I've been able to reset it then redo the time, date & settings.

 

Came in just now to the downstairs heating off and couldn't reset the controller this time. 

 

Changed the electrolytic, new one apparently Panasonic brand.

 

All appears to be working again. Thanks all, especially Jeremy.

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  • 2 weeks later...
  • 1 month later...

A sh!t end to today! Supposed to be going out, wife had shower, I went for one and she informs me there's no hot water, "the heating's on all the time". I thought the place was uncomfortably warm today but didn't give it a second thought as in and out all day. I did on passing the downstairs stat turn it down from 30 to 25. Thought maybe she was drying washing on the radiators.

 

The lower controller then that does downstairs CH and HW had really had it. Won't even work resetting it. This was the one I replaced the capacitor in.

 

20181215_083114

 

No problem I thought I'll swap them over and reprogram the one that did upstairs CH to do downstairs CH and HW. Didn't admittedly check whether that was working before I removed it.

 

Couldn't make it up but that's now died as well! :( Won't reset same fault as the first. What are the chances???

 

Before I buy two of these is there a better alternative?

 

https://www.amazon.co.uk/Grässlin-Temperature-Control-Switch-White/dp/B079TYWWP5

 

Cheers

 

(Pumps leaking too one side just noticed when up in the loft. Where everything's been running flat out all day?).

 

Edited by Onoff
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31 minutes ago, PeterW said:

How many channels do you need ..? If it’s 3 just get a new single clock that does the lot. 

Good shout. 2xCH + 1xHW. What's a good one?

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Numpty question:

 

Why is there a SATISFIED connection on a cylinder stat when there isn't on  room stat?

 

As I understand the room stat; clock calls for heat via terminal 4 on the controller and goes to COMMON on the room stat. If bi-metallic strip is closed then the stat DEMANDS heat, fires the boiler via the 3 port valve. Room heats up, bi-metallic strip in the room stat opens, no more DEMAND, boiler stops.

 

2018-12-21_09-18-32

 

So why the need for the SATISFIED connection on the cylinder stat? 

 

Why can't it just be a case of bi-metaĺlic strip opens when the cylinder reaches temperature and boiler stops?

 

And why does it go back to 1 on the controller unless it's to do with the unused terminal 2, CH off? 

 

20190226_061519.jpg

 

I must be not understanding something obvious, apologies!

 

Thanks.

Edited by Onoff
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26 minutes ago, dpmiller said:

guessing it's to give DHW priority over heating?

 

But with my wiring plan I can have either CH, DHW or both so guessing that feature / SATISFIED wire is redundant? 

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Ok so that’s just for a mid position valve wiring as if you give it grey and white by either heating on, and hot water off or hot water satisfied, it will push the valve across to the heating only port. 

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30 minutes ago, PeterW said:

Ok so that’s just for a mid position valve wiring as if you give it grey and white by either heating on, and hot water off or hot water satisfied, it will push the valve across to the heating only port. 

 

Thanks. If, with the controller removed and the base plate exposed I jump L to 3, will that fire up the boiler to give me a tank of hot water? The cylinder stat should then do it's thing and cut heating when the stat temperature is reached.

 

It'll be a day or do for the new controller.

 

Likewise can I jump L to 4 on both controller bases and get CH back controlled solely by the room stats?

 

Cheers

 

20190226_061519.jpg

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