This preheater bad idea?

#1: Post by **marteccino** » March 18th, 2023, 5:40 pm

Thinking what adding something similar before the boiler would do to temp stability ... And I wonder how its temp is regulated since I don't see thermostat only voltage connectors...
And it looks like PID wouldn't be possible either since it has no thermocouple connection,
But
Could its thermocouples be connected to switch on power once the brew is on only? Or it would overheat the water?

Have no electricity knowledge, so not sure how it would be connected, but thinking to add PID to the brew boiler and then this U shape preheater before the boiler that would switch only when brewing water passing through...
Not good?

#2: Post by **pizzaman383** » March 18th, 2023, 5:46 pm

My brother uses a similar device (one that has spots for mounting thermocouples) controlled by a PID to preheat water going into a Gaggia Classic boiler (which is also separately PID-controlled). He gets very stable and repeatable temperature control.

March 18th, 2023, 5:54 pm

That's great. Did he write some summary how he did it and which part preheater he used? Saw few bigger thermoblocks. But this simple U shape heater seems like straightforward approach.
I have no electric knowledge and not sure how the cables would be connected to the the voltage power at this time, but pump would be affected by thermoblock being on during extraction, but in my opinion temperature has much more effect on coffee extraction taste than pressure...

#4: Post by **bgnome** » March 18th, 2023, 6:31 pm

marteccino wrote:Thinking what adding something similar before the boiler would do to temp stability ... And I wonder how its temp is regulated since I don't see thermostat only voltage connectors...

image

That's a steam boiler for Gaggia / Saeco semi-auto and super-auto machines. It usually has a steam thermostat (maybe thermofuse) mounted to it, which is wired in series with the element. When in steam mode, there is a hall sensor on the steam valve that triggers the pump to pulse at 1 or 2 Hz to push hot water out of the boiler and through the steam thermoloop.

March 18th, 2023, 7:07 pm

So that would be a bad idea just connect it to the brew switch to be on during pump running? There would be that interference with pump but for me temp more important than ~1 bar plus minus fluctuation vibe pump.
Or connecting it directly to power during brew this steam would overheat and consequently pressurized boiler with steam?
In that case PID better but mounting thermocouple might be a challenge then
Idk, my small boiler is still a guessing game so was thinking this might preheat incoming water

#6: Post by **JRising** » March 18th, 2023, 8:14 pm

marteccino wrote:So that would be a bad idea just connect it to the brew switch to be on during pump running?

It would need some sort of thermostat, but the little Saeco thermostats are cheap anyway. I figure that the reason for wanting this horseshoe steam generator is simply to pre-heat the water going to the boiler (kind of increasing the size of the boiler by 30 or 40 milliliters and adding a second element)...
Luckily, its temperature wouldn't matter, it would just need to stay somewhere around a cheap thermostat's 97 to 105C range so that the water arriving at the real boiler isn't affecting boiler temp so much. Screw any cheap "Klixon" type thermostat to it with a nut.
The 2 holes are where the thermostats are typically mounted. One for working temp. and one reset-able safety.

#7: Post by **ira** » March 18th, 2023, 8:25 pm

If it's only on while the pump is running it probably will not need anything as the water will likely be moving to fast to get hot enough to boil. But adding a thermostat is still likely a good idea in case you grind to fine and stall the shot. You should consider how you control this as if you turn on this and the normal heater and the pump all at the same time you might pull more current than the outlet is rated for. Additionally, you might have to rewire the machine so the drive to the pump also controls a relay that turns on this heater.

#8: Post by **cafeIKE** » March 19th, 2023, 10:57 am

JRising's answer is the simplest solution.

You should replace the power switch with a higher current model as there will be a fair inrush when powering both elements.