The Bosch Greenstar is a gas condensing boiler with an efficiency rating of up to 96.1% AFUE. All models of the Greenstar series are Energy Star rated. The Greenstar features a wall-hung design and is available as a space heating boiler with a hot water tank or as a combi unit. It features an Al-Si heat exchanger made of Aluminum-Silicon alloy, and combi units are equipped with a stainless steel heat exchanger. A fully modulating fan assembly helps to increase the unit’s efficiency. All models are available for use with LP or natural gas, with a conversion kit included.
As a certified installer, I've got to agree with the comments pointing to installer error as the culprit behind the problems I've seen here. We've now been installing these for almost 5 years and have had nothing but worry free installs. We have even put these in the boss's home and her daughter's home. The installer better knows about proper gas and water piping or the unit will never work correctly. Same is true for running a combustion test at the time of commissioning. These boilers (and all boilers like them) require a combustion test. They do not just work coming out of the box. And as with all on-demand water heaters, hot water from these units is dependent on water flow. There is a low-end limit where the unit won't fire because not enough water is flowing. The most common culprits are well systems with low water pressure, undersized water lines feeding the equipment, and low flow shower heads or ones clogged by lime. Bosch recommends annual servicing, with the heat exchanger cleaned every 5 years. We have found it better to service the heat exchanger every 3 years, but that's not bad at all. Of the high-efficiency equipment we've installed over the last 20 years, these have been the best boilers by far.
"Not good for me"
Installed 2017. Not even 1-year-old; nine days, no hot water. Three parts replaced. Now the next heating season and the heat failed five days later, no hot water. This is a lemon.
Peter J Ryan
Central Islip, NY
"Great Boiler with no issues"
I had a Bosch Combined Greenstar 151 installed 4 years ago and have had no issues. Only error codes I had was to clean the porcelain pencil shaped igniter. I was told to use a dollar bill for this. I would buy this unit again and the price is reasonable. I agree with Paul from Milton, I actually had two jabrones from craigslist install it. They did a okay job but did not run the initial set up or something to that nature which prevented the system to work at its full 96% efficient capacity. I had a certified high efficiency condensing boiler repairman correct this issue.
"Best on market behind Rinnai 175 Combi at $2K more LOVE MY BOSCH"
People he is the real deal with the Bosch greenstar line. I have two 151 Combi's in my home, very large home. I have a third 131 boiler I use as my pool heater. The quality and performance you will get from your unit is largely dependent on a competent certified installer. I am also a contractor who installs the Bosch Combi unit and tankless hot water heater on a regular basis and certified from Bosch at Londonderry. There are a lot of meatball contract is out there that do not new how to commission these units meaning once it's turned on do a proper combustion analysis and adjust the fuel air ratio on high and low fire to assure the unit is working properly. If this isn't done your unit will never give you the proper hot water or heat and most likely give you frustrating error codes. This is not the fault of the unit. I have read some of the reviews here and no firsthand that the problem is with the installation not the unit there is no way on this God's given earth that this unit cannot give you 140' consistent hot water every second of every day that you have a natural gas or liquid propane feed into the unit. You can leave the hot water running from now until the cows come home and it's gonna pump out 140' consistently. On a three-quarter inch incoming cold water feed to your home you will get for outputs meaning three showers and a faucet. The only limitation is the amount of water pressure coming into your home. People think it's the unit it's not, I've seen people who have a half inch water feed coming into the home and squawk that the unit only allows one hot water point to work in the second faucet when turned on only drips out. Stop blaming Bosch and look to the source of the problem, your home not the manufacturer. Change the igniters every two years, in 8 to 10 years the fan will probably crap out just because the fan blades are so thin and lightweight and these are the only problems you should ever see with this unit which trust me are many less than the other units on the market. The Rnnai Combi at 175,000 btu is by far the best and biggest on the market at a substantially higher cost. Dollar for dollar you cannot beat a Bosch Combi for your home. People, do your homework and do your homework properly, homeowner squawking that they don't have enough heat or hot water needs to go after the installing contractor and make him do his job right or hire somebody qualified. Good luck I hope this was helpful.
"Failing after 3 years. Recommend to NOT buy"
Please do not buy Bosch. After 3 years the pressure and temperature started to fluctuate, most noticeably in the shower where the volume is highest. The pattern is consistent: Turn on the faucet, wait a minute to warm up, then 2 minutes of hot water, followed by a minute of dropping temp and a full 2 minutes of cold water. Then 1 minute to ramp to hot, and the cycle continues. Water pressure follows the temperature arc (highest pressure when hot, lower pressure when cold). The original licensed HVAC installer swore he knew the issue from across the room without ever touching the unit. He had his guy swap out the impeller. No improvement. This self-proclaimed HVAC genius then said he was "stumped" and suggested we add a small mixing tank to the system. I disagreed, since our hot water demand hadn't changed and the boiler provided more than sufficient hot water for the first 3 years without issue. We have had a well serviceman, a plumber and an electrician grace us with their bills and they all left scratching their heads. I've come to the conclusion that the Bosch Greenstar unit has a 3 year lifespan, and is designed to stop throwing codes after this point. Prove me wrong.
In comparisons on hvac-talk.com between the Greenstar and similar units by Weil-McLain, Buderus and Triangle Tube, there were several positive comments about the Bosch unit. The majority of professionals appear to prefer the other units, but not by a large margin.
Product registration is required within 90 days of installation for maximum warranty coverage. The warranty for the Bosch Greenstar boiler is comprised of the following:
Limited lifetime heat exchanger warranty, pro-rated after the 10th year
Limited 5-year parts and labor warranty
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