Condensing boiler cleaning hilarity

Constantin

Hi everyone, it's been a hot minute, the mere HO is back. Hope you all (and your loved ones too!) are well and warm.

I've been having some fun here and thought I'd share the experience for comment. Specifically, it deals with cleaning the passages inside condensing boilers, which is a job that I'm sure all of us enjoy immensely. After years of dealing with phosphoric acid, a thin OEM-approved breadknife, etc. I decided to try something else, and now have a few years of experience with it.

Specifically, I sourced a inexpensive pressure-washer with a variety of jets and a 90* tip attachment that allows me to stick the wand straight into the combustion chamber, yet shoot water streams that are perfectly aligned with the gap between my HX coils.

If the stream aligns and the passage is clear, there is little to no overspray. When it doesn't or there is stuck debris, things can get moist in a hurry. I move the wand in a circular fashion, following the gap and work my way forward from the back. These days, it is a 10 minute job and there is almost no overspray.

To protect the controller, I put a trash bag over the controller, a rag at the bottom of the case over the controller, and fit a wide-mouthed wet vac intake to the bottom of the mouth of the combustion chamber with duct tape. As a result, even the trash bag stays dry except for a drop here or there. Afterwards, I vac and wipe down all adjacent surfaces to ensure they are dry.

In years past, the bottom of the chamber evidently did get wet as "coffee grinds" blocked the slinky coil passages, resulting in damage to the combustion target. Now, the chamber still fills with grinds but the target shows little to no discoloration, spalling, etc. suggesting that the boiler has much better drainage.

I wonder, has anyone else tried this approach?

PS: I would not use this technique with a plastic outer-walled HX assy used by some OEMs - the outer walls in my chamber are SS.

HomerJSmith

How does your idea deal with hard combustion deposits? I do have a portable steam generator that I use for cleaning baseboards. I wonder how that would work. I'll try it on my boiler which is due for a cleaning.

It takes me 2-1/2 to 3 hrs to do a good cleaning.

Constantin

As best as I can tell, they get broken down and then blown out. Perhaps the water helps soften them?

I find little to nothing in the P-trap, which is what I clean after I clean the boiler. The water flow from the pressure washer is much greater than what the boiler usually produces (drip, drip vs. steady flow) so I don't think the sauce / debris is accumulating in the annulus between the boiler chamber wall and the HX.

mattmia2

The pressure washer probably erodes it.

I have an HTP UFT-100 and the instructions about cleaning are very cryptic, consequently I have ignored it completely. I think the fins in the water tubed are aluminum since it clogs the condensate neutralizer with a white gel.

Constantin

It claims a SS HX... one of the selling points for downwards-firing HXs like AIG out of Poland is that they are allegedly self-cleaning. If it's a AIG, it will say so on the outside, along with how many sq feet of HX area the thing has, etc..

If this was a slinky-coil HX like Sermeta / Giaonni / Viessmann / etc. then cleaning it in this orientation would likely be impossible with a pressure washer unless you removed it from the case. For that matter, you'd likely need multiple elbow / wrist joints to clean this unit if it was a Slinky-coil unit by hand also, so my guess is a AIG or eqv.

hot_rod

I met with a pressure washer manufacturer last year at AHR, about developing one of these kits.
These are usually supplied by the boiler chemical companies, Sotin for one, in the UK and Europe. Looks like Amazon.de has them

It would involve multiple adapter plates for the different brands of water tube type boilers, removing the target walls also.

I would imagine part of the fire tube design could also be pressure washed.

Every one needs a ****. -1 of course.

https://www.sotin.de/produkte-kataloge-ratgeber-filme/filme-produktanwendung/

Constantin

That is a really neat product, especially given the lengths they go to ensure a dry home - little to no overspray possible. They don't seem to stock a solution for the 35kW model I have, which is kind of odd given that the HX size doesn't jump until the next size up, IIRC.

With the 90 degree turn and a 0* nozzle as I use today, it is very evident when you encounter debris in the HX passages - water shoots back. With the Sotin design, you hope that with enough time and back and forth that the bulk of the passages will be clear, but I'd check as a lack of debris in the waste water and clear passages inside the HX are not necessarily 100% correlated.

Importantly, I also learned I should remove the combustion target prior to cleaning (forgive me, for I have sinned).