Buderus Hardware Help

gcdchico

Just purchased an older home that has Buderus G234 boiler (approximately 24 years old) plus Buderus Logalux SST 250-65 indirect storage tank. The system currently supports both home hot water and floor radiant heating. The home is 3400 Sq ft with 3 bath rooms. The previous owner NG bills are around $600/month. I'm considering installing a NG Tankless system for the homes hot water and just use the Buderus equipment for radiant floor heating. PLEASE let me know what you recommend. TAHNK YOU - GREGG

Ironman

Why do you want to do this?

Choosing a tankless water heater over a boiler with an indirect would be a mistake. I doubt that it would save much, if any, and would require a lot of maintenance. It’s also extremely difficult to find anyone that knows how to repair them when they break - which is far more frequent than a cast iron boiler with an indirect. So, what little you save on fuel will be far less than what you pay in maintenance and repairs. Not to mention the cost of installing one.

Don’t believe all the hype about huge energy savings with one. Testing has shown that they only saved $36 a year on average over a conventional water heater.

EBEBRATT-Ed

And cost much more than $36 to service. They are nothing but trouble.

gcdchico

Thanks Ed. I appreciator your help. -Gregg

9326yssh

Agree about tankless cussing more issues then help, but $600 per month is a lot is that your price now in the summer as well?

Ironman

If the system is set up and adjusted properly, the boiler should only run to heat domestic water when there’s a call from the indirect through the 2107 Logamatic control on top of the boiler.

The Logamatic control operates from a heating curve which means it doesn’t call the boiler on for SPACE heating from a thermostat demand, but instead, it uses an outdoor sensor and water temperature sensor to regulate the boiler’s water temperature. This is known as outdoor reset (ODR). It also has a feature known as warm weather shut down (WWSD). This turns off SPACE heating at around 68* outside. The control probably has a radiant heating card installed which operates a mixing valve for a lower heating curve for the radiant floor since the boiler must operate at a warmer temperature to prevent flue gas condensation.

I suspect that something (maybe a bad outdoor sensor) is keeping the boiler on all the time at a high temperature resulting in excessive fuel consumption.

Unfortunately, the Logamatic control is no longer available from Buderus unless there’s one on a shelf somewhere. There are other aftermarket controls that can be incorporated by a competent tech should the Logamatic be faulty.

The boiler is the best cast iron made and was the most efficient system around when it was installed. I believe the AFUE rating was 84%. If properly maintained, it could easily last 40+ years. The indirect, depending upon water conditions, 25-30 years on average.

I would recommend that you get someone like @Alan (California Radiant) Forbes to evaluate the system and see what needs to be done to correct any issues. Again, it could be something as simple as an outdoor sensor gone bad.

If the time comes, or has come, for a system replacement, a 95%+ mod/con boiler with fire tube heater exchanger + a new indirect would be the best way to go.