I had to cut the HX line to insert a T so I have a place to tap my pressure gauge. The machine fittings are metric so I had to make use of the OEM fittings. After getting the gauge, mount, pipe and fittings I cut the HX line. To my surprise, a standard ¼" pipe fitting does not fit the factory pipe, it must be metric as well. To fix the problem I had to use the OEM fittings and sweat a ¼" pipe into them. Not what I had planned on but thankfully I got everything together and sealed.
I installed my T and ran my pressure gauge line over the top of the boiler and pre-existing lines. From the 'out' side of the T, I ran a line along the side of the boiler to about 1" from the end. Then I looped it under the boiler and back to top. Then I ran it back the full length of the boiler again. This is my preheat line for the HX. Then I ran this into an elbow and down to the original HX input. The parts are labeled in the photo.
I decided to rearrange the original gauge placement. The new pressure gauge was too deep to mount it where I wanted, and the existing boiler gauge has a nice ring around it which would conceal any irregularities in my hole. So I remove the OEM boiler gauge and mounted my new pressure gauge in that hole. Then I marked the outer circumference of my newly relocated boiler gauge onto the face of the machine.
Now for the hardest part of the entire project, cutting a 1.5" hole in that thick stainless steel. I decided to drill smaller holes just inside the mark and then use a carbide cutter in my rotary tool to connect the dots. I was using general purpose drill bits in a hand drill, trust me, if you decide to drill into this stainless steel, don't use a general purpose bit. I spun out (sheared off the cutting edge) on three drill bits and had not made one hole. So off to the hardware store, I purchased a set of dedicated cobalt bits designed for drilling stainless. The right tool for the job makes all the difference, these cut through that SS with no problem.
After drilling around the perimeter, I connected the dots with my carbide cutter, now I had a roughed out hole. Make note of the wood behind the hole. If you drill a hole in anything, you should have an appropriate backstop to prevent damaging anything behind your work surface. These bits would cut a copper line in seconds (or drill into your boiler) safety first.
Once I had the hole, I rounded it out with my cutter, and then ground it out to smooth the edges and shape the hole. Then I mounted my boiler gauge in my newly cut opening and hooked it up. Power the machine up and pressure test everything with a blind basket, then let it heat up and check for leaks again. I repeated this process several times just to make sure there were no leaks.
Now I wrapped the boiler in foil backed pipe insulation. I insulated the HX preheat line but left the T exposed. While my gauge is rated for quite a bit of heat, why tempt fate. So the T is isolated from the boiler heat to reduce the heat transferred to the new pressure gauge. I also insulated the hot water line. The entire boiler is not covered, I left both ends exposed and a little of the boiler back (where I could not quite reach). This still allows some heat to escape up through the cup warmer but provides enough insulation to heat the HX preheat line and significantly reduce my boiler cycle time.
Then I buttoned it up, cleaned it up and reinstalled it and hooked up my water supply line.
The boiler cycle time is significantly reduced. My cooling flushes are now much longer than before due to the preheat line. However, the extraction temp is now much more stable. Using my E61 mounted thermometer
, I was getting around a 1 degree drop over the extraction time, now it is more like .4 of a degree. Now before anyone yells about the inherent inaccuracy and latency of the thermometer, let me say I know. But using it as a general guide, I get a much flatter temp than before. My first shot from the machine was very, very good. One of the best I have pulled, and I attribute that to the preheat loop and boiler insulation. If anyone wants to loan me a data logging TC and a thermofilter PF I would be happy to run some real tests!
My hot water dispenser also gained a few degrees thanks to the boiler insulation and insulating the water dispenser line leading from the boiler. One unexpected bonus, steam power, I have a very noticeable increase in the volume of steam because the boiler holds a higher, steadier temperature
The work was worth the end result. The pressure gauge is nice, but the insulation and HX preheat loop made a big difference. I plan on posting a bit more detail as well as more photos on my blog in a day or two if anyone is interested in more detailed photos and descriptions.
One side note unrelated to the mods, my green ready light has been illuminating sporadically for a couple of months now, works some times, doesn't others. It is not critical since I know when my machine is heating because of the red light and I can hear the boiler heating. Anyone else have this problem? Anyone from WLL reading this, I am pretty sure it is still in warranty.