Cheap heater/thermostat for warming cabinet.

[pbh4]

Just came across this aquarium heater for £22 including postage from China.

http://www.virtualvillage.co.uk/aquarium-heater-and-thermostat-300w-50hz-003600-111.html

Looks like it would be excellent for a DIY warming cabinet. It even has an LCD display! A bit more controlled than the traditional lightbulb I would have thought.

(Please note, I have never dealt with this company. This is not a recommendation or otherwise)

Paul

 

[oliver90owner]

Just came across this aquarium heater for £22 including postage from China.

Not read the link, but IF it is really 'including postage from China', the package may well cost another packet to get it imported. Import duty, VAT and the charge of about nine(?) quid (for collecting those aforementioned taxes) will add best part of another fifteen quid to the bill.

RAB

 

[Luminos]

Aquarium heaters usually have to be used underwater.

 

[Russel]

Aquarium heaters usually have to be used underwater.

Yep,they can overheat and blister other wise!

 

[drstitson]

better to get one of the cheap PID controllers off fleabay - will optimise themselves to the vessel characteristics then control temp to within a degree.
just need to wire up with a lightbulb or warming mat as heat source.

 

[The Cumbrian]

Aquarium heaters usually have to be used underwater.

Would Vivarium heaters and thermostats not be a better bet for this sort of thing.

 

[pbh4]

better to get one of the cheap PID controllers off fleabay - will optimise themselves to the vessel characteristics then control temp to within a degree.
just need to wire up with a lightbulb or warming mat as heat source.

That's the route I would go myself. For someone uncomfortable with wiring it all up I thought the aquarium heater looked like a nice solution.

 

[pbh4]

Just came across this aquarium heater for £22 including postage from China.

Not read the link, but IF it is really 'including postage from China', the package may well cost another packet to get it imported. Import duty, VAT and the charge of about nine(?) quid (for collecting those aforementioned taxes) will add best part of another fifteen quid to the bill.

RAB

Well, there's no import duty for goods less than £135 and no VAT below £18. The price without postage was £17.99 so it should be okay.

 

[The Cumbrian]

That's the route I would go myself. For someone uncomfortable with wiring it all up I thought the aquarium heater looked like a nice solution.

Basically that is why I was suggesting the Vivarium set up. Something like a Habistat allows you to lug the heat lamp into it so no complicated wiring.

 

[Bee-Key-Pur]

Would Vivarium heaters and thermostats not be a better bet for this sort of thing.

That's what I use inside an old chest freezer and it works great....

 

[DulwichGnome]

This would need to go inside the cabinet but looks as if it could work for non electricians.
http://www.ebay.co.uk/itm/Plug-Ther...arden_Hearing_Cooling_Air&hash=item2567c530ee

Or one of these if you are competent,
http://www.ebay.co.uk/itm/SALE-Simp...arden_Hearing_Cooling_Air&hash=item2c5c951bd8

Mike.

 

[DorsetB]

Nonononononononono.

Apart from the additional costs you may be landed with at the door, aquarium heaters should only be used when immersed.

There is a vague clue in the Chinglish listing:

"the heater rod is submergible whilst the control unit must be placed away from the water".

Although this one is metal and will probably just overheat and burn out, I've lost count of the glass ones which I have seen cracked or burst.

Lastly, despite the fact that they will kindly send you the appropriate country specific adaptor, those US style flat pins can get very hot if under load for extended periods.

... plus I think mains powered stuff from China is still a bit iffy, getting better though.

Have a look at Dealxtreme, they may have some type-approved stuff, and they now have a UK warehouse, so delivery is about 3-4 days and shipped from within the UK so no additional duty etc to pay..

 

[Norton]

I bought an electric drill that was supposed to have been made in Italy - actually it was Chinese and cost 7,50. I thought I had a bargain until I tried to drill a hole and it caught fire!

 

[chalkie]

How about one of these http://www.ebay.co.uk/itm/Thermosta..._Reptiles_Spiders_Insects&hash=item19b3949ee1 all you would then need is to plug in the bulb.

 

[oliver90owner]

The price without postage was £17.99 so it should be okay.

I think you would find that shipping costs are actually included within in that nineteen pounds limit! Might be lucky and avoid any charge, but one must be aware that it could be expensive.

RAB

 

[Bee-Key-Pur]

How about one of these http://www.ebay.co.uk/itm/Thermosta..._Reptiles_Spiders_Insects&hash=item19b3949ee1 all you would then need is to plug in the bulb.

Yes, that's the kind I use and it works well...

 

[itma]

better to get one of the cheap PID controllers off fleabay - will optimise themselves to the vessel characteristics then control temp to within a degree.
just need to wire up with a lightbulb or warming mat as heat source.

For the control side of things, a PID is going to be more trouble than its worth.

I use one happily in my home-made sous vide cooking setup.
But its neither good nor needed for keeping a fridge with a variable amount of honey (or homebrew, or incubating salami) at a set warmth.

The variable thermal mass (full/not with honey, etc) screws up the PID settings, and autotune involves a temperature overshoot - and the less responsive the system, the bigger that tends to be.

Simpler and better to use an ordinary on/off ('Bang-bang') controller, if at all possible with a specialist air (gas) sensor probe.
I've heard good reports of this type of unit http://www.ebay.co.uk/itm/Mini-Digital-Temperature-Controller-Thermostat-Aquarium-/260841088348
Because the thermal capacity of the air is so low, even a controller with a couple of degrees hysteresis isn't going to cook the honey.

But a small ex-computer fan, to keep the air well mixed, and thus the temperature even throughout the box/fridge, would be a worthwhile refinement.

 

[Hombre]

better to get one of the cheap PID controllers off fleabay - will optimise themselves to the vessel characteristics then control temp to within a degree.
just need to wire up with a lightbulb or warming mat as heat source.

Does the controller come with the PT100 or other sensor, or is that something else that is required?

 

[itma]

Does the controller come with the PT100 or other sensor, or is that something else that is required?

I think most PIDs come with a K-type thermocouple included in the deal.
Most are able to be used with a variety of sensors (check the spec) and you connect appropriately and then tell it (in the settings) what you've attached.

Note that some PIDs have a relay output, others a signal to drive an SSR. Some have both - but not always both for the PID signal. (Relay 'alarm' outputs are common.)

My understanding is that a 3-wire Pt100 probe compensates for errors such as those arising from using a connector to attach/detach the probe.
Not so with a thermocouple. Each connection has the potential to introduce errors.

For my sv kit, I bought a "fully immersible" Pt100 probe (and because of the postage charge, a gas sensor K-type probe as well) from Auber in the USA. http://www.auberins.com


But I really wouldn't recommend a PID for a honey-warming cabinet ...

 

[oliver90owner]

But I really wouldn't recommend a PID for a honey-warming cabinet ...

I would agree as it is only the air temp which needs to be kept at the correct value. The heater will normally either be on or off (unless its triac controlled)? Sizing the heater properly, for fewer on/off cycles is the trick here, I would think, unless stirring the honey and using a PID, while measuring the honey temperature as the control value (and it's a bit difficult to stir the honey until at least part- liquid). Simple case of patience (air to honey bucket heat transfer is not as good as a water to honey bucket system). Better to warm evenly for a little longer than overheat locally but save a small amount of time...

RAB