Where to stick me probe (a HERMS question).

[markpeace]

Hi all,

I've bodged me together a heat exchanger, and got an STC 1000 and this weekend I'll be trying it for the first time in a brew. I'm trying to decide where to put the temperature probe for this one, though, and was wondering if anyone could offer advice?

Eventually, I'll plumb the probe into a thermowell at the exit of the HEX, but for this one I'll be bodging. I thought about taping it to a small length of copper that already sits around the exit bit, and wrapping it with insulation - but I'm not confident that the stock probe that comes with the stc1000 is up to the job. Alternatively, I've though about feeding the probe up the tubing that returns the wort to the tun, so that it sits half way.

Any thoughts?

M.

 

[graysalchemy]

Don't know myself but thought I would give you a bump up. :thumb:

 

[Springer]

Don't know myself but thought I would give you a bump up. :thumb:

He's a good lad that Grays.
I can't answer this as well Mark, but I will give it a shot. :lol:
For HERMs you normally use a PID, STC are first rate for fermenting cupboards and fridges, really first rate :thumb: They will not however been sensitive enough for HERMs. PIDs learn the heating and cooling rates and pulse on off with a solid state relay to keep temperature at set value, i.e. not just on or off .
Your question on where to put a probe, you have answered, on the HE out.
The bit I am not sure about is whether those senders are waterproof, I have had failures on PT100s so am putting even those in thermowell to be sure, so certainly I would put STC1000 ones in a well to my mind.
I don't think you will get an accurate reading with the sensor stuck to a pipe, unless it is very very well insulated.
Hope this helps :)
I d
S

 

[evanvine]

Springer is right, you need to use a PID not an STC1000
This is the way I monitor my HEX out temp.
The pic is just a dry setup, the "T" needs to slope down towards the HEX a little more to ensure the probe tip is fully immersed (bottom 15 - 20mm).
The thermo well in the HEX is for preheating.

 

[Springer]

By the way Mark did you see this ?
Is HERMs worth the effort
S
P.S. I have not given mine up for good, am redoing the HE, but have lived without it (missing it for bottle washing. :lol:)

 

[markpeace]

Cheers guys. Yup, I've read around the controversies surrounding HERMs. Ultimately, the build is cos I like building things, which is a fine justification for me :).

Thanks for the advice. I'll look to use a PID eventually, though for now, I'm swapping and changing my STC between the fridge and this. It seems to be keeping my test run (just water) within 1/2 degree, this seems precise enough for now? Or am I missing something?

M.

 

[Springer]

Cheers guys. Yup, I've read around the controversies surrounding HERMs. Ultimately, the build is cos I like building things, which is a fine justification for me :).
M.

Thats fine

It seems to be keeping my test run (just water) within 1/2 degree, this seems precise enough for now? Or am I missing something?

M.

:hmm: Probably. What are you checking your temps with, cos STCs are +/- 1 degree. :? :) (As I have said, don't get seduced by the displays. :lol:
Temps can vary alot, remember my finding

The picture shows temp measurements being taken last time I was on my "HERMS worth it" horse. :) :lol:
Smug 66 on the herms out , STC monitoring tun out at 62 :shock: , wandering probe in mash showing 64 :) , (not allowing for instument measurment variations) :hmm: :lol:
As you say part of the fun is experimenting, good luck, don't forget to post up your findings so that we all learn.

S

 

[evanvine]

Looks nice and tidy at the back there S. :whistle:

 

[Vossy1]

Cheers guys. Yup, I've read around the controversies surrounding HERMs. Ultimately, the build is cos I like building things, which is a fine justification for me

A fine reason for a build
I'm not sure if you're aware that STC100 are only rated to 10A so you need to be careful what size element you're using (assumes you're using one).

 

[markpeace]

Thanks guys. As it stands, I'm heating my strike water using a boiler mounted thermometer that I don't quite trust, so I guess I'm just shifting to something that I can't trust, but at a more precise level of mistrust :) . I'll give it a go and take some temperature readings at various points in the system using a glass jam thermometer and report back!

And yep, I picked up on the thread about load on the stc1000 (I wouldn't have thought of it otherwise!) - my element should only draw 9 amps.

 

[Springer]

Arrrrrrrrrrrrrrrr...............yes E, quite right. :) The pic was taken a couple of years ago and its still the same, probably worse. I will tidy up...........I am always tidying up, but I make more mess than I tidy, anyone else have this problem. ?

Can use a relay with the STC, V. I believe the ones that Cedars does have one installed :?

Sounds like a plan Mark, that will eliminate thermometer error, or at least it will be a constant one.

S

 

[tazuk]

here is mine aka tesco kettle

 

[Vossy1]

Re probe position, as near to the HE exit as possible as per springer is the 'norm'. When testing for the 1st time make sure the wort exiting into the tun is the same temp as that measured by your HE probe, as your HE probe could be reading 65 deg c but your exiting wort could be reading 63 due to heat loss from the pipes etc.

Over the years I have to question the position of the HE probe. I know placing it closest to the HE exit ensures rapid reaction to temperature changes, but TBH I see no reason why it couldn't go on the exit into the mash tun (not in the mash), in fact I think it would be better as it would take out the variable of heat loss to surroundings/system between HE and mash exit :hmm:
If your exiting HE pipework is well lagged there should be little heat loss to surroundings but why take the chance as it's the one variable that can change with ambient temps.

 

[Springer]

:hmm: Now you challenging the boundaries V. :lol:
I will think about this when I have not been sampling. :) :lol:

S

 

[tazuk]

so i am not far off at all just return pipe ext to mash needs sorting on mine :thumb:

Re probe position, as near to the HE exit as possible as per springer is the 'norm'. When testing for the 1st time make sure the wort exiting into the tun is the same temp as that measured by your HE probe, as your HE probe could be reading 65 deg c but your exiting wort could be reading 63 due to heat loss from the pipes etc.

Over the years I have to question the position of the HE probe. I know placing it closest to the HE exit ensures rapid reaction to temperature changes, but TBH I see no reason why it couldn't go on the exit into the mash tun (not in the mash), in fact I think it would be better as it would take out the variable of heat loss to surroundings/system between HE and mash exit :hmm:
If your exiting HE pipework is well lagged there should be little heat loss to surroundings but why take the chance as it's the one variable that can change with ambient temps.

 

[evanvine]

TBH I see no reason why it couldn't go on the exit into the mash tun

Thought that was what I was doing JP!

 

[markpeace]

So I tested it today, based on a probe shoved up the return pipe. The temperatures through the system were fairly tight together, and the ramp between them was good - though a tendency towards a bit of an overshoot. OG of wort was as predicted, though my taste buds tell me it wasn't as sweet as it should be, so I suspect its too unfermentable (never mind, it was a 7% recipe, so a bit lower isnt a disaster).

My copper pipe manifold, however, is not up to the job (it'd just a length o' copper with slots), and this caused all manner of juddered and stucknesses. So my next task is to bodge up something new.

 

[tazuk]

did you try slow pump down a bit have a play with pump speeds :thumb:

 

[markpeace]

Yeah, but it was doing shudders even on when my return valve was only just open. It eventually settled down, but I think the recirculation may have been a bit slow.

 

[Springer]

Glad its comming together Mark.
Not thought about probe location and I've been sampling again, it is Saturday. :lol:
Werever the probe goes you need to know what is coming out the mash tun, so a temp measurement there can do not harm for sure, if its the same as H.E. out and its your design temp you have cracked it.
Pump bypass rather than pump speed is....... was my method of operation.
S