Buderus GB142 Heat Exchanger Replacement Question

GB142

I have been operating my GB142 since 2006. I have done most if not all the maintenance myself, albeit, in the beginning, years not quite as vigilant as I am today.

I have an appliance maintenance plan, so whenever I was in need of anything to be replaced, I called and a new part was ordered. Last year I had a small condensation leak and thought my HX was going to be done, but after having done some reading I purchased high temp silicone and used it to seal the left side where the block meats the tubing. So far so good.

Today, since it's that time of year and winter is around the corner, I decided to clean the HX. I had not done so since last year. At first, it seemed pretty crusty, but it in fact was mostly all ash not mineral crust like years past. No doubt it was due to the heavy concentration of mineral oil I used to clean it last year.

I also noticed my lower pan drain pan whole was nearly plugged shut. Wondering if that may have caused more backup.

Also, please look at the one photo of my fins around the lower left side where the gases escape. The fins are more corroded with some actually missing. Is this normal given it's age? Or, normal given its location being right above the condensation fluid as it exits?

QUESTION:
My GB142 is likely near the end of its life. A new HX can be had for around $1000, but I was told that it would be very very difficult to install and should just go ahead and replace it when the HX fails.

Can someone shed light on just how hard it would be to install a new HX. All the tubing and everything is there versus having to replumb the whole thing if I go with a new unit.

EdTheHeaterMan

Both about the same on the plumbing side. drain boiler > remove HX from boiler > test for leaks > fill boiler > put everything back.

The electric and venting may be a bit more time consuming. This is assuming that your new boiler will not be a GB142

You can order a replacement bottom pan and that will have a clean drain opening. You can get another 15+ years from it. (the pan not the HX). If the HX is not leaking, keep using it. It will still work in that condition. Just a little less efficient. You could get another 5 to 10 years from that.

As long as you are not having blocked flue issues, keep it running.

EdTheHeaterMan

BTW. I have replaced that HX in the past. You are almost there! 3 water connections to go. Then there is a few sensor wires to remove.

SuperTech

I personally don't like that boiler. I've run into too many with similar problems like you described. I would replace it with a mod con with a fire tube heat exchanger if you are using it for radiant heating. Something like the Weil McLain 97+ is a lot less finicky and easier to maintain. 

EdTheHeaterMan

...and the new boiler professionally installed is $5figures. But the HX is a lot less. Will you be doing the replacement HX as a DIY?

EBEBRATT-Ed

I would continue running it. The cost of the replacement HX is a lot less than a new boiler installed

GB142

I do all the maintenance but am not up for swapping out the boiler myself. I would have to hire that out. If the boiler can be had brand new, that seems to be the easiest and fastest. But then I am using a 15-year-old system/technology, and not to be confused with a cast iron boiler that can go for many more years. My brother inlaw just installed an NTI and seems to be happy with it.

I cleaned out the drain pain very well.I used sandpaper to get rid of the majority of the build-up and a round file to clean out the drain hole. I should work fine now, but if it's covered under my maintenance, I will take your advice and ask for it to be replaced. See pics

BTW, here is what my leak looked like (before and after shots) in the summer of 2021 and now over a year later it's still holding up after I cleaned it out and filled it with +500F silicone

Also, how do I know when my ceramic burner needs to be replaced? Should I assume it is time to replace it or do they go forever? see my pics

mattmia2

If that drain pan is aluminum or some sort of pot metal it is going to corrode with the condensate. I would just keep cleaning the scale off until it either corrodes through or it damages the sealing surfaces.

EdTheHeaterMan

Ceramic burner looks fine.

You said
"I cleaned out the drain pain very well.I used sandpaper to get rid of the majority of the build-up and a round file to clean out the drain hole. I should work fine now, but if it's covered under my maintenance, I will take your advice and ask for it to be replaced. See pics"

Who is responsible for "Covered under my maintenance" when you stated you DIY the maintenance? This sounds like one of those questions you must ask yourself. Let us all know what the answer is after you ask!!! We all want to know if you cover that!

chrishmhtghlp

In similar boat. HX apparently started to leak last heating season. Internals all caked up. Cleaning it this year actually unclogged the leak! Officially toast as of yesterday. I’m having a lot of trouble removing it. The supply line on the bottom has a tension clip which came off easy, however I cannot get that pipe to separate from HX so I can, per the flue adapter instructions “pulling forward and then pushing up” to remove the HX. 

Any tips? 

Figure the $1,300 in parts between HX, seals, replacement sump and nuts, ignitor and limit sensor way cheaper than the quote I got last week for new boiler. Even if I only get 5 years out of it, I’ll take it.

Big Ed_4

Yes that top union to the boiler is the **** . Best cut a slot in the union nut to break tension and remove . You would need a new nut and lock clip . The boiler is a work horse , Very easy to replace heat exchanger .

doninbc

This is a very useful discussion of GB142 HX options. It answers many of my questions. I have GB142 that has been in service for 13 years. It has been quite reliable and has no major issues. So I'm thinking of replacing the HX if it starts giving me problems.

I have one strange issue. I think the boiler is a GB142-45 but I haven't been able to verify that so I don't know which HX to purchase. I've searched the web with all of the numbers that are visible but I haven't got any satisfaction.



I've attached some pics of the boiler. There are a couple of numbers that are visible, including 423.245EB09440517 and 87470210-03-0050-0478. There is also an number on the right side casting (423 023E).



Also notice that the info plate says that the "Heating Surface" is 34.44 sqft.



Can anyone tell me what model my GB142 is?

Mad Dog_2

Measure the Block and call Chuck Shaw at Bosch/Buderus tech support.  He'll tell u  mad Dog 🐕 

Big Ed_4

I believe the label is on the left outside of the cabinet . Yours seems fine ...

Alan (California Radiant) Forbes

The HX looks in good shape, but that’s only from the outside.  

Teemok

Mixed feelings about that old bird. I've seen them taken care of, in good application and they've done well. I've also found twice as many in the gutter, leaking, clogged, spewing Co from holes that were not meant to be. Fun fact: Those are unions that are hard to bust. Move on, there are better boilers.

Mad Dog_2

Agreed...we put in many of these when they first came out ...They were Sleek & real  Nice Looking, and performed Well against its Gold Standard Competitor, The Viessman Vitodens. The Vitodens WAS 2.5-3.5 Times the price of a Buderus GB...A much harder sell.
Ours performed very well, Despite!, the Aluminum Block HX that wore out eventually after 15-18 Years...not a bad run!  The Germans were in the Lead and Pioneers in those early days and many others soon showed up and did a very good job.  

Today, Viessman is thankfully much more competitive and is easier to sell, especially with their unmatched High qaulity, great warranties & longevity. The first thing you notice is how much Heavier a Vitodens is than an equal BTU output Other brand Mod Cons .nolo contendre...I still love 💘 ❤ 💕 the Cover and "softer" plusher look of the GB-142 Cabinet versus the Neat but  Stark, Boxy, sqaured edged Vitodens...gotta go for utility & longevity over "Better" looks.  I'm with the boys..Unless you are getting the HX FREE   new Boiler time!   Mad Dog 🐕 

doninbc

Thanks.  Does Chuck Shaw at Bosch/Buderus tech support happen to have an email address? If not, which tech support phone number should I use?

Mad Dog_2

Just any..ask for Chuckie...He's awesome 👌  mad Dog 🐕