Digital Thermometer & Adaptor for E-61 Groupheads September 13, 2014 Introduction: The purpose of this adaptor and digital thermometer is to facilitate the measurement of brew water temperature about 1.25" (3.2 cm) away from the puck during a brew cycle. In addition, and EQUALLY IMPORTANT, it measures the temperature of the grouphead at the indicated location under idle conditions.
Background: This adaptor is identical to the original thermocouple adaptor except that the “boredthrough” size of the fitting is 1/8” (0.125”) vice the original adaptor which had a boredthrough size of 1/16” (0.0625”) and the overall length is increased by about 3/16”. In addition, the width of the 7/16” (~11 mm) hex on the main body is shortened to enable installation in all machines without adding any additional copper washers as spacers.
The digital thermometer kit currently ships with a Taylor Model 9840N thermometer that is user switchable from degrees F to degrees C. The Taylor 524 thermometer, which was also user switchable, was temporarily discontinued by the manufacturer. Installing the Digital Thermometer and Adaptor: (the quick install procedure) Machine should be at room temperature (or maybe 15 minutes into a warm-up), turned off, and unplugged. Remove the M6 hex head screw with a 5 mm hex key wrench.
Clean the sealing surface with a Q-tip or equivalent. Now separate the thermometer and adaptor exactly as shown below.
Screw the main body of the adaptor into the “hole” finger tight using a new copper washer. Make sure that the adaptor is fully seated. Now tighten the adaptor 1/8 of a turn using the box end of a 7/16” (11mm also works) combination wrench or a small adjustable wrench. Insert the thermometer with 7/16” nut and ferrules into the adaptor as a unit. The thermometer probe is designed to stop at the proper insertion depth.
Installing the Digital Thermometer and Adaptor: (the long installation process) When the digital thermometer adaptor is used in a Quickmill machine (Alexia, Andreja, Anita, or Vetrano) or any other machine that utilizes the “standard” E-61 grouphead ( Isomac, Izzo, Rocket, Vibiemme, etc.), the probe will come already adjusted (approximately) at the proper depth and the nut will be a heavy finger-tight.
The picture on the left above shows how the thermometer & adaptor should look upon receipt. Unscrew the 7/16” nut and remove the thermometer, nut, & ferrules as a unit as shown on the right picture above. Set the thermometer, nut & ferrules aside for the time being but be careful that the ferrules do not fall off and disappear “forever”. Remove the existing M6 x 8 mm allen-head capscrew using a 5 mm long-handle allen wrench.
Now, install the thermometer, 7/16” nut, and ferrules (all as a unit) into the adaptor and tighten the 7/16” thermometer nut loosely FINGER-TIGHT. Orient the thermometer properly and adjust the thermometer’s height depending upon the particular thermometer being installed. Current production kits require no height adjustment. Now turn the 7/16” nut 3/4 of a turn (270 degrees) past finger tight, maintaining the proper orientation of the thermometer itself.
Reinstallation of the Digital Thermometer: While is it certainly best to use new ferrules when reinstalling the thermometer, old ferrules can be reused but the 7/16” thermometer nut is simply snugged up past fingertight and NOT tightened as per the instructions for new ferrules. The nut goes on first, then the back ferrule (NOTE THE ORIENTATION as shown in the first illustration of this document), and finally the front ferrule.
Everybody has a different pressurestat (pstat) setting – sometimes whether you like it or not. It is not unusual for gages to be off by around 8% and just the variation in altitude between two users can result in a boiler absolute pressure difference of 0.2 bar. I currently have my pressurestat set to a maximum reading of 1.20 bar (light probably goes out at ~1.15 bar) as this appears to provide a reasonable balance between the amount of flushing, the machine recovery after a shot, and steaming power. a.
started and heat is being drawn OUT of the grouphead. The grouphead temperature starts to head DOWN. Above I have a graph that is a magnified version of the 70 to 110 second interval – the scale is changed to magnify the dip.
Operation of Espresso Machines which require little or no flushing: There are two (at least for now) double-boiler E-61 machines and three heat exchanger (hx) machines which require very little flushing. The double boiler machines are the Alex Duetto and the Vibiemme Double Domobar; the hx machines are the Vibiemme Domobar Super, and the entire line of Rocket Espresso machines. These two hx machines are fitted with thermosyphon restrictors (2.80 to 3.
Digital Thermometer Maintenance: The battery installed in the Taylor 3516 (and spare) is a model number G10-A or G13-A and is an alkaline battery. The EXACT “Energizer” replacement for the G10-A has model number 189. Radio Shack, Energizer, Duracell, and others have a model 389/390 that is a BETTER equivalent battery in that the cell composition is silver oxide vice alkaline.
and the EXACT “Energizer” replacement for the G13-A has model number A76. The battery installed in the Taylor 9840N and 9841 is model number G13-A and is an alkaline battery. Radio Shack, Energizer, Duracell, and others also have a MODEL 357 that is a BETTER equivalent battery in that it too is silver oxide vice alkaline. The battery in the digital thermometer is designed to operate continuously for one year and I typically leave mine on for days at a time.
With newer thermometers, the battery is held in place by frictional contact with an upper tab – no bending is necessary. The contact tab near the center of the housing should be at about a 20 degree angle before the replacement battery is installed. This will ensure good contact on both terminal faces. The above illustration details the parts of the battery housing.
Battery Replacement – Taylor 508 & 524 Thermometers: Remove the thermometer from the adaptor as previously described. Fully loosen the 7/16” nut at the top of the adaptor body and remove the thermometer, nut, and ferrules from the adaptor body as a unit. The battery installed in the Taylor 508 & 524 is a lithium cell CR2032 battery and is a very common “button-cell” battery available in many stores. The battery should be replaced when readings grow dim or irregular.
Battery Replacement – Taylor 9840N shipped during 2011 & later: Remove the thermometer, nut, and ferrules (as a unit) from the adaptor as previously described. These batteries are held captive simply by the spring tension of the center tab and an additional tab pressing on the battery top near the outer edge. It is NOT NECESSARY to bend any tabs; simply use a small screwdriver to push the battery out towards the inside of the case. The recommended battery replacement is an Energizer Model 357.
Enhanced Kits: The primary purpose of the adaptor is to allow the use of the modified digital thermometer to assist in making your espresso better and more consistent. However, once the adaptor is installed, there are very inexpensive options available that would greatly enhance the utility of the adaptor. These enhanced kits are priced separately as shown in the Pricing_Inventory_Ordering pdf document, which is available here: http://users.rcn.
Installation of the Enhanced Pressure Measuring Kit: Note the approximate distance between the bottom of the thermometer and the top of the 7/16” nut on the adaptor. This should be 3/16” to 1/4” for the 3516, 9840, and 9841 thermometers and approximately 7/16” for the 508 and 524 thermometers. Remove the thermometer, nut, and ferrules as a unit as previously described.
Checking the Accuracy of the Thermometer: This is something you would NOT NORMALLY do, but it does prescribe the procedure I utilize. The digital thermometer included in each kit is not capable of being calibrated but it is easy to check its accuracy and speed of response by suspending the tip into the steam portion of a covered pot of boiling water or a thermos jug/jug cap filled with a distilled water / ice slurpy mixture. Note your current altitude, e.g.
Another method of “checking” YOUR digital thermometer kit is to immerse the thermometer tip in a covered short thermos jug filled with a mixture of crushed, distilled water ice and distilled water – think of a flavorless coarse slurpy. This method is nice because it is independent of altitude and barometric pressure but needs about 15 minutes or so to stabilize around the established freezing point of water (32.0 F). Each digital thermometer sold direct ships with a tag attached to the probe stem.
Spare Parts: Nylon ferrule set 6 mm copper washer 7/16” Nut Plug Batteries Swagelok P/N NY-200-SET Copper sealing washer, 6.2 x 9.
Warranty: For the first 30 days – full refund of monies exclusive of postage will be made upon your request AND upon receipt of product. The thermometer, attached probe, and any purchased accessories are guaranteed to be fully functional for 1 year from the date of purchase. The stainless steel and brass adaptors, excluding the ferrules and copper washers, are warranted to the original purchaser for life.
Frequently Asked Questions (in a very random sequence) 1. How “custom” is this adaptor? Can I get spare parts readily? The particular adaptor currently has a 4 to 6 week lead-time – is this custom enough for you? All of the parts, which make up the adaptor with the exception of the body, are “off the shelf” parts, typically stocked by Swagelok distributors. Even if the part(s) is not stocked, it would be available in a couple of days – they are all standard catalog items.
2. Is it OK to take the adaptor apart when I get it? You certainly can but be sure to take it apart on a soft, dark surface with a “mandrel” of sorts slid inside. This is to minimize the chances of dropping small, almost translucent, parts (which you would be hard pressed to find) all over the floor. The ideal mandrel is any smooth 1/8” diameter “rod”, e.g., a 1/8” drill bit, 1/8” tubing, possibly a smooth 1/8” wooden dowel, or the thermometer w/ attached probe itself. 3.
7. Are there any special instructions for E61 heat exchanger machines? Yes, please read the document entitled “thermocouple adaptor tidbits” available from my FTP website: http://users.rcn.com/erics/ . In addition, there exists an abundant supply of well-written and informative articles on hx machine operation, particularly on this website - http://www.home-barista.com/ .
with use. HOWEVER, thermometers with the soft touch buttons and automatic shutoff have been shipping for a couple of years now with no reported problems. 12. What can you say about the quality of the thermometer and/or thermistor? Well, ahem, ahem, I’m glad you asked this also. We have all seen the dozens of digital thermometers available in stores and on the internet. Heck, just do a “google search” on [digital thermometer] and sit back a while.
17. Are there any other uses for this device that you can think of? When your espresso production is over for the day and your machine has been on but idle for at least one hour, do the following and record the results, along with the date. Record the maximum pstat reading (boiler pressure) and grouphead temperature. Start the “timer” and flush till the thermometer reads temperature “A”. Let the machine recover to temperature “B” (rising to, not falling to).
