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Date: 01 Nov 2006 05:41:00
From: Robert Harmon
Subject: Plan of attack for PIDing my Bunn ES-1A
Howdy Folks!

Here's how I plan to install the PID on my Bunn ES-1A. I'd appreciate it if
the resident guru's of PID's for HX machines would take a look at my wiring
specs.
---------------------------------
I'll use a Watlow 935A PID, a Crydom 40 amp SSR, a Type T thermocouple
(mounted in the unused pstat steam port in the boiler), a 45 Amp SSR
w/protective plastic cover.
---------------------------------
The wiring looks straight forward;

Terminals #1 & #2 on SSR connect to severed brew t-stat wires (2 ea 14 ga
red wires) (polarity not important)

Terminal #3 (+) of SSR connects to PID terminal #4 (22 ga red wire)

Terminal #4 (-) of SSR connects to PID terminal #3 (22 ga white wire)

Two 20 ga black wires from main power switch connect to PID terminals #7 &
#8 (polarity not important)

Thermocouple red wire connects to PID terminal #1 (-) (does polarity
matter?)

Thermocouple blue wire connects to PID terminal #2 (+) (does polarity
matter?)

I will ground (14 ga green wire) whatever enclosure is used (if used; I may
install this through a cut out in the S/S front panel, in which case an
additional ground wire would be unnecessary).
---------------------------------
I plan on doing away with all t-stats, the PID will account for the brew t-
stat & a 184C thermal fuse (I trust them a lot more than I do a mechanical
t-stat) will account for the high limit t-stat.
---------------------------------
I think I've about covered the wiring. Other than my uncertainty about
polarity of TC wires do you see any holes in my plans?
---------------------------------
I should have this finished & pics posted by this weekend.

Robert (Bunn lovers have a different perspective.) Harmon
--
http://tinyurl.com/pou2y
http://tinyurl.com/fkd6r
Remove "Z" to reply via email.




 
Date: 01 Nov 2006 21:20:18
From: jggall01
Subject: Re: Plan of attack for PIDing my Bunn ES-1A
Eric Svendson wrote:
> Set up your PID (if not already set up) and, with it as far from the stove
> as possible, stick your TC at the midpoint of a pot of boiling water or a
> covered distilled ice slurpy and make any necessary corrections to the PID
> readout. You need to know your altitude and barometric pressure.
>
> I would probably split the correction factor in the two methods.
>
> Probably won't need much but hey every bar, er degree F counts.
>
> Eric S.
>

I have come to prefer the distilled ice slurpy (I learned it from Eric
S., BTW) because it is so hard to get a stable reading in boiling
water. And the "right" answer varies with local barometric pressure.
Too complicated - violates KISS principle.

I use water taken from a dehumidifier and freeze it in old-fashioned
(?) ice trays. Dump a couple of trays in the blender, add distilled
water until ice just covered, then give it a couple of quick shots
(garita consistency is good). Pour the slurry into an insulated
plastic jug like the kids use at soccer.

Plunk your t/c about 2-3 inches below the surface of the slurry, turn
on the controller, and go have a couple of adult beverages. Give
everything at least 30 minutes to settle, then adjust the CAL parameter
on the 935 until it reads steadily at 32F. Depending on how long ago
your particular 935 controller hardware was calibrated, you may need to
dial in as much as +/- 4F correction (more commonly 2F or less).

I think you will find that the single calibration point at 32F will
yield very good results throughout the small range of temps you will be
dealing with. I have adjusted many controllers this way, and then
checked "higher" temperature readings (~230F) against an accurate
digital thermometer - with very close agreement (less than 0.5F
variation).

Aren't you done with this installation yet? Must be a long halftime
;-}

Jim



 
Date: 01 Nov 2006 23:13:25
From: Eric Svendson
Subject: Re: Plan of attack for PIDing my Bunn ES-1A
Set up your PID (if not already set up) and, with it as far from the stove
as possible, stick your TC at the midpoint of a pot of boiling water or a
covered distilled ice slurpy and make any necessary corrections to the PID
readout. You need to know your altitude and barometric pressure.

I would probably split the correction factor in the two methods.

Probably won't need much but hey every bar, er degree F counts.

Eric S.

"Robert Harmon" <r_h_harmon@Zhotmail.com > wrote in message
news:Xns986DF0EE65DD3rhharmonZhotmailcom@207.217.125.201...
> Howdy Folks!
>
> Here's how I plan to install the PID on my Bunn ES-1A. I'd appreciate it
> if
> the resident guru's of PID's for HX machines would take a look at my
> wiring
> specs.
> ---------------------------------
> I'll use a Watlow 935A PID, a Crydom 40 amp SSR, a Type T thermocouple
> (mounted in the unused pstat steam port in the boiler), a 45 Amp SSR
> w/protective plastic cover.
> ---------------------------------
> The wiring looks straight forward;
>
> Terminals #1 & #2 on SSR connect to severed brew t-stat wires (2 ea 14 ga
> red wires) (polarity not important)
>
> Terminal #3 (+) of SSR connects to PID terminal #4 (22 ga red wire)
>
> Terminal #4 (-) of SSR connects to PID terminal #3 (22 ga white wire)
>
> Two 20 ga black wires from main power switch connect to PID terminals #7
> &
> #8 (polarity not important)
>
> Thermocouple red wire connects to PID terminal #1 (-) (does polarity
> matter?)
>
> Thermocouple blue wire connects to PID terminal #2 (+) (does polarity
> matter?)
>
> I will ground (14 ga green wire) whatever enclosure is used (if used; I
> may
> install this through a cut out in the S/S front panel, in which case an
> additional ground wire would be unnecessary).
> ---------------------------------
> I plan on doing away with all t-stats, the PID will account for the brew
> t-
> stat & a 184C thermal fuse (I trust them a lot more than I do a mechanical
> t-stat) will account for the high limit t-stat.
> ---------------------------------
> I think I've about covered the wiring. Other than my uncertainty about
> polarity of TC wires do you see any holes in my plans?
> ---------------------------------
> I should have this finished & pics posted by this weekend.
>
> Robert (Bunn lovers have a different perspective.) Harmon
> --
> http://tinyurl.com/pou2y
> http://tinyurl.com/fkd6r
> Remove "Z" to reply via email.




 
Date: 01 Nov 2006 19:34:10
From: I->Ian
Subject: Re: Plan of attack for PIDing my Bunn ES-1A
On Wed, 01 Nov 2006 05:41:00 GMT, Robert Harmon
<r_h_harmon@Zhotmail.com > wrote:
>Two 20 ga black wires from main power switch connect to PID terminals #7 &
>#8 (polarity not important)

A 500mA FUSE for the PID in the LINE would be a nice touch.

>
>Thermocouple red wire connects to PID terminal #1 (-) (does polarity
>matter?)
>
>Thermocouple blue wire connects to PID terminal #2 (+) (does polarity
>matter?)
>

On a T thermocouple, the - wire is copper, the + constantan. The
Red/Blue designation could be confusing as a red wire is often +, as
on a battery


  
Date: 01 Nov 2006 20:48:41
From: Robert Harmon
Subject: Re: Plan of attack for PIDing my Bunn ES-1A
"I- >Ian" <someone@nowhere.com> wrote in
news:r2shk2hfa3lge5etjvgpss7o0d557p17t8@4ax.com:

> On Wed, 01 Nov 2006 05:41:00 GMT, Robert Harmon
> <r_h_harmon@Zhotmail.com> wrote:
>>Two 20 ga black wires from main power switch connect to PID terminals
>>#7 & #8 (polarity not important)
>
> A 500mA FUSE for the PID in the LINE would be a nice touch.
>
>>
>>Thermocouple red wire connects to PID terminal #1 (-) (does polarity
>>matter?)
>>
>>Thermocouple blue wire connects to PID terminal #2 (+) (does polarity
>>matter?)
>>
>
> On a T thermocouple, the - wire is copper, the + constantan. The
> Red/Blue designation could be confusing as a red wire is often +, as
> on a battery
>

I knew I forgot something. I'll run down to the Shack & pick up a fuse &
inline fuse holder.
-------------------
So, here's my layout for the wiring.

SSR terminals
1 - red AC wire to severed brew thermostat wire (no polarity)
2 - red AC wire to severed brew thermostat wire (no polarity)
3 - red DC wire (+) to PID terminal #4
4 - white DC wire (-) to PID terminal #3

Thermocouple conductors
1 - red conductor (-) to PID terminal #1
2 - blue conductor (+) to PID terminal #2

PID terminals
1 - red conductor (-) from TC
2 - blue conductor (+) from TC
3 - white DC wire (-) from SSR
4 - red DC wire (+) from SSR
5 - unused
6 - unused
7 - black AC wire w/inline fuse from main power switch (no polarity)
8 - black AC wire from main power switch (no polarity)
-------------------

I will use an aluminum enclosure I fabricated to enclose the PID, which
will be mounted through the front panel, just above the pump. As
suggested I will ventilate the enclosure by using a high-volume 120v fan
vented to the exterior through inlet & outlet ducts.

I'm considering putting a thermal fuse inside the enclosure to protect
the PID in case the fan fails. The 935A's specs give it a max operating
environment of 65C/149F, so I'm thinking a 60C/140F fuse should be on the
safe side.
-------------------

Robert (Thanks Jim, for all your help!) Harmon
--
http://tinyurl.com/pou2y
http://tinyurl.com/fkd6r
Remove "Z" to reply via email.


   
Date: 01 Nov 2006 21:24:02
From: I->Ian
Subject: Re: Plan of attack for PIDing my Bunn ES-1A
On Wed, 01 Nov 2006 20:48:41 GMT, Robert Harmon
<r_h_harmon@Zhotmail.com > wrote:

>
>I will use an aluminum enclosure I fabricated to enclose the PID, which
>will be mounted through the front panel, just above the pump. As
>suggested I will ventilate the enclosure by using a high-volume 120v fan
>vented to the exterior through inlet & outlet ducts.

You don't need to move all that much air to keep it cool. It consumes
only 6VA, so a fan barely ticking over will keep it cool. Add a bit
for heat absorbed by the enclosure. You don't want is a machine that's
roaring all the time...

Don't forget to put a filter on the inlet side and remember to clean
it.

>I'm considering putting a thermal fuse inside the enclosure to protect
>the PID in case the fan fails. The 935A's specs give it a max operating
>environment of 65C/149F, so I'm thinking a 60C/140F fuse should be on the
>safe side.
Use a resetable device. You don't want to have to disassemble the
machine to replace a one time device.


 
Date: 01 Nov 2006 18:33:12
From: Barry Jarrett
Subject: Re: Plan of attack for PIDing my Bunn ES-1A

ventilate it. 220v muffin fans are available through grainger (or off
my parts shelf).