Well a subject thats strangely appropriate to the time
of year as we shall see!
I have been searching for some time to find a low cost and suitable
material for boiler insulation. Many of the products on the market are for kilns
(expensive), or are what I consider unsuitable such as glass fibre (rockwool),
or metallised/foil backed plastic.
The boiler runs at around 128C in an
HX machine, so you need a product that will withstand that temperature. This in
reality means a product stable at least to 180C or better. The product also
needs to be flame retardant and use man made fibres (as natural fibres are
likely to degrade over time, e.g. damp, rot, heat), but be food safe!
I
have finally selected a product, which meets all the main criteria I originally
set myself for boiler insulation. This is no joke by the way, perfectly serious.
The product is called The original Buffalo Snow Tree Skirt
OK down to details, the product states (on the packaging) that it melts
at 232C, it's 100% Polyester and is flame retardant. Now the 232C is no
guarantee of stability at a continuous temperture of 112-128C when surrounding a
coffee machine boiler, but it's a reasonable bet that it's going to be OK and
not harden or disintegrate with use.
I have yet to fit this stuff but
when I do, I will avoid one area of the boiler, the ends of the heating element
(Only because I suppose it's possible that those terminals could actually become
hotter than the water and the boiler itself). I intend to fold it double or
triple and only insulate the boiler, but NOT cover electronic components or
valves such as the vac breaker or pressure release etc..
To attach it to
the boiler, I used cable ties and very thick cotton based
string
This stuff was bought at my local
Focus (do it all) DIY store, but it (and similar products) can probably be
bought in a wide range of places. The cost was £2.99 and there is enough to
insulate at least 2 boilers.
Well here it is, "i'm dreaming of a white Christmas" with my " Buffalo Snow
Tree skirt
I had 3 reasons for doing it:
1. The beast is hot and
I think my Gicar box and other components may last longer. Also I don't burn my
fingers on the cup tray any more!
2. I can run the machine at 0.6 bar,
much less heat energy, cooler group, smaller flush, steaming not as effective
but with insulation, heating element can easily "catch up". Boiler now at
112C instead of 122C. Although the machine can be run at lower pressure, running
at 0.9 to 1.1 bar does give better steaming performance, which is desirable when
offset against doing a slightly larger cooling flush.
3. Less stress on
the pressurstat microswitch and heating element
The differences in
element timings are marked
On for 10 seconds, off for 2 minutes
(previously on for 15 seconds off for 50 seconds). I also do have a tiny tiny
steam leak from near the autofill (vv small leak), and sometimes vac breaker
doesn't seal perfectly, so it may be cycling a little more than it should. All
in all a success so far, ut will know for sure when I check the material in 2
weeks time and then a months time. I think it will be OK tho, and the string, no
problem, in fact I think it might last a lot longer that the plastic cable
ties!! It's very thick and robust and doesn't burn on meat in the oven!!
