13A/3kw temperature controller?

[Kev888]

Hi all,

I'm thinking of getting a new temperature controller for my HLT; in the past I've added a big relay to an ATC 800+ and that worked well so may do it again (or else get a PID/SSR combo, though thats a bit overkill for my simple needs).

But thought I'd ask first; would anyone recomend a temperature controller that can natively switch a 3kw (13A) element with ease?

Cheers,
Kev

[polymoog]

Kev sorry to bother you but if your ATC800 with a relay worked before why not do it again?
the reason i ask is that ive purchased a 30 amp relay my self to go with my ATC 800 and am hoping to connect it all up this weekend, only im not 100% sure on the connections.
Thanks Polymoog

[Kev888]

Hi,

whats motivated this is that I actually want another FV cupboard controller and my ATC with its heating and cooling (currently unused/wasted on the HLT) circuits would be excellent for that. So I was thinking maybe I could get a cheaper/simpler controller specifically for the HLT and swap the current ATC to FV duties. If not though I'll just get another ATC as the current one plus relay has been performing faultlessly on the HLT.

Happy to help out with the wiring, though I'm away this weekend from Friday pm unfortunately. All i did was to switch the relay's coil with the ATC output (and switch the element with the relay's switch contacts) so it wasn't too complicated at all in the end.

Cheers
Kev

[jmc]

Hi

Kev sorry to bother you but if your ATC800 with a relay worked before why not do it again?
the reason i ask is that ive purchased a 30 amp relay my self to go with my ATC 800 and am hoping to connect it all up this weekend, only im not 100% sure on the connections.
Thanks Polymoog

What sort of relay did you get?

Something like this relay from Maplin N24AW version?

I too would be grateful for some info on how to set this up as my HLT is 3KW too.

TIA
John

[Kev888]

I rather crammed the relay and wiring into the box so you can't really tell whats what from seeing it, but I can have a go at a circuit diagram if that would help?

Cheers
Kev

[polymoog]

Thats exactly the relay i have bought and despite studying the diagram ive seen im still not sure.
Of all the different things ive built for my new brewery this is the thing im least sure about, and i guess subconsiously ive been putting it off for as long as possible
any help you gan give will be much appreciated
thanks polymoog

[Kev888]

I had a go at doing a drawing:


The left hand side is from the Fortex instructions, with the ATC switching the live to the socket directly. In the right hand side the ATC switches the live to the relay coil instead, and the relay switch/contacts (which are of course rated for higher current than the ATC) then switch the live to the socket. I'm assuming a domestic 13A plug on here, if you're using an industrial plug or other means of connection then you definately need to know what you are doing and don't forget suitable fusing/circuit-protection/isolation.

EDIT: Please take note that this is going outside the instructions that come with most temperature controllers, so don't attempt it if you're at all uncertain of how to do so safely.

EDIT2: I've had a few PMs from someone about the use of high current relay. So to clarify for other readers: this circuit assumes connection via a normal 13A plug with a 13A fuse in and so should supply no more than 13Amps or a 3Kw load. The use of a higher rated relay (such as the 30A maplins one) does NOT increase the maximum that can be drawn from a domestic plug for supplying the heating element, the extra switching capacity of the relay is merely a margin for safety; it is prudent to have such a margin in order to maintain the relay's contact life whilst switching the heavy, difficult loads it may experience (it can very briefly experience much higher initial currents as it makes the contacts to supply power to a cold element). This is a high power, high voltage circuit - if you are not comfortable in understanding and choosing suitable ratings of ALL the components, leads, connectors etc in such a circuit I would STRONGLY suggest that you do not try this alone.

Cheers
Kev

[jmc]

Hi Kev

That's just the job.

Thanks a lot.

ATB
John

[polymoog]

Wow Kev,

Thats brilliant thanks ever so much,very clear easy to understand, even i should be able to manage to follow that.
Ill let you know how i get on after the weekend,
Thanks Polymoog

[boingy]

Just a small clarification for anyone else wanting to used an external relay like that. The relay coil must be a 240 volt AC type. Many relays have low voltage DC coils and would just go bang in that circuit.

Kev, rather than buying another ATC, take a look at the other controllers Forttex do. They have a cheaper one that does heating OR cooling. It's smaller, and the user interface sucks but it works well on my HLT. And a while back a few folks bought a similar one off eBay for even less cash.

[Kev888]

No problem chaps, glad it helps and the best of luck with it!

Just a small clarification for anyone else wanting to used an external relay like that. The relay coil must be a 240 volt AC type. Many relays have low voltage DC coils and would just go bang in that circuit.

Yes indeed, in fact all components (cables, wires, plugs, fuses connectors etc) must be rated for the power and voltage; the relay coil should therefore be rated at 240volts ac and it should have contacts rated well in execess of the 13A (again at 240Vac) - so the 240vac version of the maplins relay in John's link above should be very suitable.

Kev, rather than buying another ATC, take a look at the other controllers Forttex do. They have a cheaper one that does heating OR cooling. It's smaller, and the user interface sucks but it works well on my HLT. And a while back a few folks bought a similar one off eBay for even less cash.

Ah yes, thats an idea, thanks. If I couldn't find a 13A controller I'd imagined going for an 800+ just to make it interchangeable with my other one, but having cooling at the same time would indeed be wasted on the HLT, so the saving may well be worth it. Thanks for the heads-up on the interface too; whilst I'm fairly able with such things I do get easily irritated by needlessly fiddly or poor interfaces.

Cheers
kev

[mark]

forrtex.com
The TC10 is not quite to your spec, but it may do the job for you.
•Control Temperature Range: -40C to 60C (-40F to 140F)
•Operating Temperature: -10 to 55°C
•Relative Humidity: up to 85%
•Sensor: NPT
•Cooling Relay Capacity: 16A : 3800W (max) 240V AC
•Heating Relay Capacity: 10A : 2400W (max) 240V AC
•Power Supply: 240V AC ± 10% 50 to 60Hz
•Normal Consumption: <2W
•Delay Protection Time Setting: 0 to 255 Minutes
•Unit Size: 75 x 38x 70 mm (W x H x D)
•Sensor Cable Length: 2 metre

[Kev888]

Hi, Thanks for the thoughts.

Yes, i'd looked at the TC10 but unfortunately the temperature range isn't high enough, I'd need to go to at least 85c or so really. The one that I was thinking of was the ETC-200+, but actually looking at the prices its very £similar to the ATC-800+ and I think with its password protection and menu system and so on its probably designed for a different (and less immediate) type of control.

Of course a PID & SSR from hong kong would probably be cheapest and there's no doubt that it could do it, but thats overkill and probably too fiddly/complex in use to be quite what I'm after for my simple needs. I think if I were to go that way it'd be the STC-1000 if its specs are suitable.

But the conclusion seems to be that none of the cheap and/or simple controllers can natively switch 13A so some sort of external relay will be needed with all of them. Which in a way is good I guess, as it opens up the range of choice. So, I think its coming down to the STC-1000 or the ATC-800+, of which the former is cheaper but the latter has a better interface for what I'm after and would be directly swappable with my FV controller if required.. another ATC-800+ it is then!

Cheers
kev

[boingy]

another ATC-800+ it is then!

Yep, having looked at the prices now I think that's a good call. I'm sure there was about a tenner difference when I bought mine.
The ETC-200 is much smaller, which is an advantage (I couldn't believe how big the ATC-800 was when I bought mine!) but as I said the UI stinks. You really need to keep the instruction sheet to hand because all the parameters are just called, for example, "F08" so you need to know that this is the "mode selection" and that 0 is cooling and 1 is heating (yes, I just had to look that up). Consequently I just leave it set to 80C, which works out fine for my setup...

[Kev888]

Great, it was mainly the interface that I'd based the decision on, but only from looking over the ETC's instruction sheet, so thanks indeed for that first hand info - very reassuring. The ETC-200 does look good and has some interesting functions over my ATC-800 though, if I were using it differently (or had it still been much cheaper) it would definately be a contender.

Yes, the ATC-800 is quite big isn't it? I've actually grown to like that in some ways - I can tell at a glance into the room what things are doing. Though i've got one on a FV cupboard in what passes for my concervatory, which can attract the attention of even quite distant passers by, especially at night.

Cheers
kev