New-to-me VAM 1.0 (Arrarex Caravel) - Page 2

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JohnB.
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#11: Post by JohnB. »

I never used mine with the 220v element so I can't say. I start off with either tea temp water from the Speedster or our hot water pot so it gets to shot temp fairly fast.
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vberch (original poster)
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#12: Post by vberch (original poster) »

Thank you, guys!!

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vberch (original poster)
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#13: Post by vberch (original poster) »

I just heard back from Francesco. He said there should be no problem installing a 110v heating element since VAM machines were produced in 110v and 220v, and the parts were the same. He said that the microswitch is not made of plastic and should be 6 amp, so it should work at 110v and 550 watt.
drgary wrote:Vlad, I've got the 110 v heating element and it is holding up. Since yours is more collectible than mine, you might want to run it in native mode on a transformer to avoid rewiring. Francesco could probably advise you well on that choice. BTW, for fast warmup, I quickly bring water to a boil on an induction range and pour that into the tank. From there it takes less than 10 minutes to stabilize.
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vberch (original poster)
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#14: Post by vberch (original poster) »

OK, I just did a preliminary temperature study. With the thermostat turned to the max, it turns off at 202F and continues to climb to 205-206F. The heating element and pilot light remain off until the temperature goes down to 187F. I can force the heating element to turn on by pressing the thermostat button, but not until the temperature goes down to 197F.

Bottom line:
1. The deadband on my VAM 1.0 is 18-19F (min 187F, max 205-206F).
2. You can lower the deadband to 8-9F by forcing the heating element to turn on and keeping it between 197F and 205-206.
3. If you are OK with one set temperature (202F) or if you want to use it as a reference point, you can predict water temperature by always starting your shots at the top of the cycle when the pilot light goes off (wait until it goes off, or if it's off, press the thermostat button and wait until it goes off).

I am very surprised how large the deadband is. I obviously can use a thermometer to nail the temperature, but I can see why it may be a good idea to have a PID.

Questions:
Do these numbers align with yours, guys? Without me setting up thermocouple in the coffee puck, do you know what is the delta between water temperature in the water reservoir and what's hitting the puck (assuming you did a few flushes and portafilter is the same temperature as the group)?

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Jake_G
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#15: Post by Jake_G »

vberch wrote:Do these numbers align with yours, guys? Without me setting up thermocouple in the coffee puck, do you know what is the delta between water temperature in the water reservoir and what's hitting the puck (assuming you did a few flushes and portafilter is the same temperature as the group)?
Gary mentioned (and is quoted by you in the first post here) that his offset is about 10° F.

There are many posts on thermometry in the massive Arrarex Caravel thread, with more than a few folks simply dropping a PID controlled immersion heater from a sous vide kit into the kettle for temperature control.

If yours switches off at 192 and peaks at 195/6, I'd first try some shots, and then see about adjusting the thermostat linkage a bit to see if I can tighten the deadband and increase the brew temp a little bit. Unless the shots were delicious, and then I'd just enjoy them :P
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vberch (original poster)
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#16: Post by vberch (original poster) »

Thank you, Jake!

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vberch (original poster)
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#17: Post by vberch (original poster) »

OK, it actually gets to full boil temperature, 212F, around one minute after the heating element turns off. With 10F offset, it's hitting the puck at 202F or slightly lower if I wait a little longer for medium roasted coffees vs. my usual medium-light coffees.

My process so far is:

- Wait (or force) for the heating element to turn on and turn off
- As soon as it turns off, weigh 12gr, RDT, grind, WDT, tamp, place an aeropress cut to size paper filter
- Raise the lever and keep it up for 4 seconds (until water stops gurgling)
- Lower the lever and apply light pressure (just the weight of my hands) to preinfuse
- As soon as the first drop appears (I am at or almost at the very bottom of the lever travel) slowly raise the lever and keep it up for 4 seconds (until it stops gurgling)
- Apply full pressure following declining pressure profile to get 14 - 15 gr out
- Do a couple of half-pulls to dry the puck


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