Dimplex Opti-Myst fires

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You need to re-tune the electronics to the fundamental of 1.7MHz.

Are there any certain single part responsible for base frequency? I.e. is it a matter of just changing some capacitor or inductance? or whole scheme needs to be reworked?
 
Just wanted to say a massive thanks for the advice, the Maplin part was fitted and is working fine, spare power supply now as well!
What experiences have people had repairing the OEM transducer disc, is it worth it? (Maybe a spare brand new Maplin part is more realistic?
Anyway - Thanks again for all the advice.
 
Just wanted to say a massive thanks for the advice, the Maplin part was fitted and is working fine, spare power supply now as well!
What experiences have people had repairing the OEM transducer disc, is it worth it? (Maybe a spare brand new Maplin part is more realistic?
Anyway - Thanks again for all the advice.

Its not possible to repair the original. Inside--its a solid plastic block (Potted) so not possible to service--just chuck it and replace it with new.
 
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Only replaceable part that Dimplex list for that later type is the disc itself.

Or you can buy a complete mist-maker as pictured above--for around £50

Better and much cheaper to go to Maplin and buy one at £20!
 
Ive been repairing these things for about 3 years now, via Ebay....




Give us a shout if you need any advice with these troublesome things.....

AlastairE - can you help?

My Piermont optimyst has a different fault. The ultrasound seems to work fine: I pull out the tray, take off the top of the tank (grey and blue) and it bubbles away nicely. But the fan isn't working to drive the smoke through the vent. The fan doesn't rotate when the fire is on but it turns fine by hand. There doesn't appear to be a voltage across the terminal block (I'm guessing that there should be should 24V). The fire was working about a month ago, but has stood since then. I have tried cycling the power a few times to no effect. Does it need a new PSU? (The lamps are on all the time, even when the tray is out: I seem to remember them turning off in the past when the tray is pulled out?). Any advice gratefully received from anyone...
 
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Better and much cheaper to go to Maplin and buy one at £20!
Much best of all, and which will sooner or later bring about the demise of this execrable product, is for people to not buy it in the first place. It's how I've decided to proceed.
 
Martinb--

Your fan is probably tight with thickened oil, and may appear free when turned by hand.--I have to clean and oil mine every year. It runs at approx 10V when first turned on (post warm-up time) for around 10 seconds--Then switched to around 5v steady-state operation. Only a very small flow of air is needed for the mist.

--The fan is a 12V part and shouldn't 'see' 24V ever! IF you have No supply At All to the fan its highly unlikely the PSU is faulty, as everything else is working--More likely the main controller board.

You can either replace the fan complete or try and oil the existing one.
 
Martinb--

Your fan is probably tight with thickened oil, and may appear free when turned by hand.--I have to clean and oil mine every year. It runs at approx 10V when first turned on (post warm-up time) for around 10 seconds--Then switched to around 5v steady-state operation. Only a very small flow of air is needed for the mist.

--The fan is a 12V part and shouldn't 'see' 24V ever! IF you have No supply At All to the fan its highly unlikely the PSU is faulty, as everything else is working--More likely the main controller board.

You can either replace the fan complete or try and oil the existing one.
 
Thanks for the advice. I'd assumed the 24V because that's the rating on the fan!

Update: (a) Fan works fine when connected to a 9V supply. (b) There appears to be just a few mV across the pins supplying the fan when the fire is turned on.

From your previous, the main controller board sounds likely. I had a look at the board within the sump but didn't think that this was the one you were talking about. Can you point me in its direction and supply me with a new one? (or is there just a fuse to replace?) Have you had this type of fault before?

Many thanks for the help - much appreciated.
 
The fan is only activated when the mist-maker is supplying mist, which happens around 1 minute after turning on the effect/fire. The parts inside the sump have no bearing on the fan or its speed. Suggest you check to confirm there's still no supply to fan while the mist-maker is making mist. If not, its a control-board problem most likely, or just maybe a fault in the wiring.

The control-board is inside the back of the fire on most models along with the lamp supply transformer which is either 12V AC toroidal or electronic halogen ballast and the 12V DC PSU for the control-board and mist-maker.

I have no source of parts other than for repairs to the very common mist-maker issue--the sump and its electronics, suggest one of the Dimplex parts suppliers for fans and control-boards, but doubt they'll be cheap...

--Seems there's different model fans for these--Mine has a 12V device......
 
The fan is only activated when the mist-maker is supplying mist, which happens around 1 minute after turning on the effect/fire. The parts inside the sump have no bearing on the fan or its speed. Suggest you check to confirm there's still no supply to fan while the mist-maker is making mist. If not, its a control-board problem most likely, or just maybe a fault in the wiring.

The control-board is inside the back of the fire on most models along with the lamp supply transformer which is either 12V AC toroidal or electronic halogen ballast and the 12V DC PSU for the control-board and mist-maker.

I have no source of parts other than for repairs to the very common mist-maker issue--the sump and its electronics, suggest one of the Dimplex parts suppliers for fans and control-boards, but doubt they'll be cheap...

--Seems there's different model fans for these--Mine has a 12V device......
 

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