Recently I had to remove the pump on my Quickmill Anita for repairs/cleaning and while I had the cover off I decided to insulate the HX pipes that lead from the boiler to the brew group.

I used simple household foam air conditioner insulation (the stuff found at stores to seal the opening around window air conditioners). I bought a pack of foam insulation for about $3.

Installation was very simple I basically pushed the foam up against the boiler pipes and allowed the foam to expand against the machine body and insulated boiler. Once expanded the foam sits in there very well. I made sure not to stress any wires or connections. Luckily the Anita is laid out nicely and easy to work on.

So I carefully checked things over and put the case back on, plugged her in and fired her up.

I knew the group would be a little warmer and closer to the peak temps of the boiler, but what surprised me is that the group (per my E61 digital thermometer) read the exact same as the peak I read when flushing.

Before the group would idle a few degrees cooler then what the read out would peak at when doing a cooling flush. Not anymore, now the readout doesn't change for the first few seconds then gradually and predictably falls like my old flushes.

I'm curious if others have done something similar and how it affected your machine/brewing practices. For my flush and go approach I really appreciate the super hot group.

What have you guys tried? Did you like it? Will insulating the HX circuit provide longer life to the electrical components inside a machine? Any other Pros/Cons that I've not thought of or seen yet?

P.S.- I also shortened all tubes so that none contact machine sides anymore and put a piece if foam insulation under the pump to dampen vibration and muffle the sound. So far the "new and improved" Anita is much to my liking.

Hi Tim -

Certainly the 10 mm lines which lead from the hx outlet to the group and then from the group to the hx inlet are a part of the thermosyphon system as the below diagram illustrates.



The "engine" which drives the thermosyphon system during normal idle conditions is the boiler water. After a flush of water through the group, the water in the hx is cooler than that in the group and the group becomes the "engine" of the thermosyphon system. This is why grouphead temperatures start to drop at the conclusion of a shot as the group, in conjunction with the heating element is adding heat to the water in the hx.

For sure, insulating the lines as you have done reduces the amount of heat offered up to the inside of the machine by the two 10 mm lines. At this point, I am unsure of the total effect this might have on the thermosyphon system but it does seem as though the pstat cycling period would increase, say from 40 seconds to 60 seconds - just a guess.

And here are some temperatures of Anita under long term idle conditions:

I would think that if you insulated only one leg of the system you could have some problems. If you insulate the upper supply line you will lose less heat in the pipe which would increase the temperature to the group. If you insulate the lower return line then the water will stay hotter leaving the group which could stall the engine. Essentially, if you do one do the other to maintain equilibrium in the circuit. Insulate just one leg and you throw the circuit out of whack.

I've noticed some odd temperature behavior since installing the insulation and it was throwing my routine off so I removed it. The stock configuration works just fine and is predictable most importantly. If it isn't broke why fix it?

Greg Scace (sp?) did a lot of experiments with changing the pipes on his Astra. You'll have to search
the alt.coffee archives via Google - Thermosyphon and maybe other keywords - gscace. What I took
away from his results is that as a tuned system, changes can be made to re-tune the system for
different results.

However, each HX circuit is unique - while there are general principles, changes to an
Anita won't always translate to an Alex. Like an electronic oscillator or analog amplifier, one
needs to know the theory, then have enough time experimenting to build up intuition.

Bob

I insulated my Expobar's boiler, and played with the HX. Based on the design of the Expobar, I wouldn't insulate its HX -- but Anitas are different.

The issue with the Expobar is simple -- the lines run too close to the electronics. With too much insulation in there, the internal temp up rises up way too high. It restricts airflow that actually does cool things a bit and no insulation is 'perfect' , leaking some heat and creating some hot pockets. I didn't feel good about the temperature tolerances on the parts I identified, so I ripped out the insulation.

BTW, I used FDA Silicon Sponge for my boiler insulation. It's far from the perfect insulator as it does retain/conduct some heat, but drastically cut down my electric bill and improved shot quality. With other insulators your mileage might be better.