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Bosch Optiflow Professional

Bosch Optiflow Professional

16L, 20L and 26L
1.2 from 27 reviews

See the Best Gas Continuous Hot Water Systems in 2019 as rated by Australians on ProductReview.com.au.

C1 error!!!!! So sick of seeing this

Purchased the Optiflow 26l, on January 2018, I have had a C1 error twice in 12 months ,and of course each time on a weekend when finding a plumber for less than $200.00 for call out and 15 minutes is impossible. I have taken 2 cold showers and boiled water on the stove for my son to bathe in. Was told the circuit board needs replacing and was even told to just replace the unit cause he’ll be back out in 3 months time to fix other things. Still waiting to hear back from Bosch. Very disappointed, not what you expect from Bosch products. If you are considering a Bosch water heater avoid it if you like hot water in the bathrooms.

Purchased in January 2018 for $800.00.

Build Quality
Value for Money
Cleaning & Maintenance
Noise Level
Household Size 3 person(s)
Smells of GasNo
Temperature Consistency
Heating Speed
1 comment
Hi Rob, thank you for leaving a review. We're so sorry to hear about the troubles that you've had with your unit. We recommend that you call an authorised service technician, whom you can find by calling 1300 30 70 37 any time from 7:30am to 6:00pm (AEST) during the weekday. If you could kindly reconfirm your details with us we will escalate and endeavour to solve this issue.

Rubbish, broke after 12 months

Unit conked out after 2 mths use, I was told by the company who installed it that they've had constant issues with this and won't install them anymore because they're rubbish and have constant problems.

Purchased in June 2018 for $730.00.

Household Size 1 person(s)
Smells of GasNo
Temperature Consistency
Heating Speed
1 comment
Hi Bek, we would like to apologise for your negative experience with our product. We'd like to hear more about your experience, if you could kindly email us at hotwater.query@au.bosch.com with your full name, contact details, and postcode. Please ensure that you leave a link to this review and we will endeavour to get in touch as soon as possible.

One year of tepid water

No high demand in house, 2 people. Can not obtain hot water for 12 months. Water is always tepid, taps and showers run for mins in order to get warm water. First time that I have filled the bath today, nearly full, cold and system is on wall of bathroom. Have had Plumber out months ago to tell me that it is set at regulation temperature and have had a meter upgrade also..Water bills have been MASSIVE as waste water trying to obtain more than warm water in shower and sinks..Worst purchase ever made!

Purchased in July 2018 for $1,500.00.

Build Quality
Value for Money
Smells of GasNo
Temperature Consistency
Heating Speed
1 comment
Hi there, we are really sorry to hear about the experience you've had with this unit. This is quite unusual and we'd like to get in touch with you but we don't have access to your contact details through this forum. Your unit is still within warranty so we'd recommend ringing us at 1300 30 70 37 (toll-free) so we can organise a warranty call out for you. Our team is available from 7:30am to 6:00pm (AEST) Monday to Friday to assist you.

Needs restarting to make hot water

We brought this product after much research and after talking to the Bosch technical staff for our campground. Had it in for several months and it just starts randomly stopping. No Hot water. All it needs is a restart to make it go again. This has caused extremely bad damage to our Brand name as we advertise having unlimited hot water for the showers. Exactly why we chose this model. Campers contacting me at 11pm to tell they want hot water!!!
Now I find it is a known problem? Whats going on Bosch?

Purchased in June 2018.

1 comment
Hi Brent, thanks for getting in touch with us regarding your issue and we sincerely apologise for the inconvenience caused by this. As we cannot access your contact details on this platform, please call us on 1300 30 70 37 (toll-free) any time from 7:30am to 6:00pm (AEST) and we will assist in resolving your problem.

Hopeless heating times

Like other reviewers, we have found the time to heat impossible. Our bathroom tap is right next to the heater - maybe 2-3m of pipe, but it takes 30 seconds to get hot water. Same problem with going cold and reheating if you turn the tap off even for seconds. The local supplier did get a serviceman out in a couple of days - they replaced the PCB but it has made no difference. I suspect it's the "efficiency" - will be pushing my builder for a different unit to replace it.

Purchased in November 2018.

Smells of GasNo
Temperature Consistency
Heating Speed

Works but noisy when not in use

Ok does it provide hot water yes. Although it will sometimes go cold at random times. The most annoying thing is the noise it makes. Every few minutes it makes a whirring grinding sound. I had the installer come out and take a look, he said it's the water pressure servo, and it's normal. Ok not happy with that answer, I called Bosch warranty line, they also told me its normal.

So really, its normal for the Optiflow to activate the water pressure servo every few minutes for the life of the machine. Even when the machine isn't in use, and hasn't been used for hours. It just keeps activating it. Don't install it near a bed room, or all you hear all night is this servo going off every few minutes.

Video of the sound here. https://www.youtube.com/watch?v=kxM039d-T1E

Date PurchasedJan 2018
Thank you for taking the time to leave a review with a link to your video. We have confirmed with the installer that the unit was inspected and found to have been working correctly. However due to your concerns, we would recommend contacting our team again at 1300 30 70 37 from 8am to 6pm (AEDT) during the weekday and we will arrange a follow up service call for you. Please reference ISSI5231.I fully accept that the unit is operating normally. And that the water servo valve is meant to kick in every few minutes for the life of the machine. I'm just warning other people about the noise it makes. And I can't imagine it would actually be good for the servo valve to operate every few minutes. I just know my next water heater won't be a Bosch.We truly value your feedback and we'd like to make sure we've done everything possible to ensure there is no issue with your unit. Unfortunately, we can't access your contact details through ProductReview, so please get in touch with our team at 1300 30 70 37 from 8am to 6pm (AEDT) during the weekday and we will arrange a follow up service call for you. As mentioned earlier, please reference ISSI5231.

OptiFlow 26 does not work. Bad Product and Bad Customer Service !

Purchased Bosch OptiFlow 26 hotwater systems last year for my new home. The very first day it was installed by my licensed plumber it did not turn ON and started leaking. The plumber suggested a replacement. I have sent many emails , phone calls to Bosch warranty but no response. Despite the unit in warranty there is no replacement and there is no response from Bosch. Unbelievable !!!

As per the supplier the unit has problems and a recall was initiated for this product. The supplier cannot offer a replacement as it was a Bosch quality issue and they do not have any units in stock. Bosch is not very open about this problem and are not at all helpful. I have seen many bad reviews about this product but the worst experience is their customer service. Will be writing to Department of Fair Trading and ACCC to complain about Bosch.

Date PurchasedJan 2017
1 comment
Hi Mick, we are disappointed to hear about your poor experience. Please be advised that we have tried to look into your issue but were unable to find your case based on the details you've provided. Unfortunately, we are unable to access any of your contact details through ProductReview. We'd like to follow up on your issue so if you could email us your full name, address, contact details, and the link to this review to hotwater.query@au.bosch.com, we will endeavour to respond to you within one business day.

My faith in Bosch brand seriously dented

My wife and I bought a house in Montville 4 moths ago with 2 guest cottages attached each supplied by a Bosch Optiflow (2X16 and 1x 26) system. Yesterday we discovered that the one was not working. I phoned Bosch service centre number 1300307037 and gave them the serial number of the unit while stressing the fact that guests would be arriving the night thereafter and that it was essential that the unit be fixed. I was assured that someone would be sent. I am still waiting.
Out of despair I contacted the local gas fitter who tried rebooting the system and then sold and installed a Dux unit which I understand is an older reliable version of the Bosch. For which I paid $951 ($850 for the unit and $101 labour)
He let me know that that he has stopped installing the Optiflow as this has given his business a bad name which he cannot afford. I have been a Bosch fan for many years with most of my home appliances having the Bosch label. My present experience has seriously dented my faith in the brand and I can only hope that Bosch discontinue selling this troubled product.

Date PurchasedSep 2018

Avoid - bad product, terrible customer service

Ordered a brand new unit, it was faulty. Bosch said they would replace it immediately. A week later and it still hasn't been replaced. I've had no water for a whole week. I've call Bosch and their service center multiple times. Despite guaranteeing it would be here within 3 days, I am still waiting.

Date PurchasedNov 2018
1 comment
Hi Emily, we are so sorry to hear about your experience with this unit. Unfortunately we are unable to access your contact details through this forum. Please email us at hotwater.query@au.bosch.com with your full name, contact details, and postcode. Please make sure to leave a link to this review and we will be in touch within a business day.

I built few Units and have 3 Bosch professional hot water 26L and it has nothing but problems.

Rubbish unit and stops hot water all of a sudden. No warnings and had to rest the power and then cal several plumber. Seriously this reviews above shows that this unit had to be recalled and it should be illegal to sell such units. I hope Bosch can respond quickly as I have completed their online complain form.

Date PurchasedDec 2017
1 comment
Hi Reggy, we would recommend that you call us directly at 1300 30 70 37 as we currently have no complaints logged in our system. Your units should still be within warranty if you purchased them last year and we will be able to organise a warranty service call for you. Please be advised that our team is available from 8am to 6pm (AEDT) during the weekday.

This product is causing lots of grief especially for family with young kids.

Imaging having to to reboot (wait for 10 sec on and off) the system at least once a day. Worst when my young kids are showing during winter and the hot water fails. Even worst - having to go outside the house and reboot the system during heavy rain. I am utterly disappointed with this product despite Bosch being a reputable brand. Please do something Bosch come on. Looking at the all the reviews here, seems like the issues are pretty consistent. I live in Brisbane and Bosch direct contractor is Gasworks. Gasworks is the company that does all my repairs and replacement.

Here's the timeline of just how many repairs and replacement made within a year. Note that I moved in to my new house in July 2016 and all appliances are brand new:

Oct 16 2017 - Unit Replacement
Nov 13 2017 - Unit Repair
Nov 29 2017 - Unit Repair
Dec 4 2017 - Unit replacement
Today Nov 30 2018 - Unit starts to show signs of trouble 3 days ago having the need to reboot the unit at least once a day.

Date PurchasedDec 2017

Unit fails to delivery hot water with out powering on and off.

Just moved into new house and this unit plays up every day, randomly, we have to turn it on and off to get hot water. Made a call over 7 days ago and no one has been yet. I have 2 kids and a pregnant wife at 36 weeks. Paid the extra for Bosch and am very disappointed.

Date PurchasedSep 2018


I moved into my home in April 2018. there was a new Bosch infinity heater on the house. this began playing up almost immediately and had to be powered off at wall then switched on for water. this was occurring every two weeks. then this would not work. So contacted the supplier, 1x week later the repairer came out and reset to factory. This worked for a matter of 1x month then stopped heating at all. meantime the water flow was like an old man with an enlarged prostrate. very poor flow. Then the unit packed up altogether. I was without hot water for 2x weeks while waiting for Australia to make a decision.
A new unit was eventually installed and within a week the water went tepid. I notified the contact people at Bosch and was told that the technician would be there that day. No show. Fortunately water heated again, but flow still poor. Then on 26 August the unit packed up again. I am now still waiting for this to be resolved once and for all. Bosch are no help and are now blaming my gas bottles. My son who is on the same property has the same bottles as I do which is 18kg. different unit, never had a problem. This is a dog, does not even rate it a star. the Service is also a dog. I would not own one given a choice. meantime I have to travel around Auckland for showers. Bosch does not care that this is happening.

Date PurchasedJan 2018
1 comment
Hi Dayle, Thanks for taking the time to let us know about your issue. We are extremely sorry to hear about the issues you are having with your unit and how inconvenient it has been for you. We would like to assist you further but we do require more information. Please fill out our Contact Form located on: https://www.bosch-climate.com.au/about-bosch/contact-us/, referring to your issue by copying in the link to your review. Once we receive this information, we’ll get in touch with you within a business day. Otherwise, feel free to ring us at 0800 54 33 52 any time between 8am to 6pm (AEST) during the weekday.

Avoid at all costs.

We had the 25E model that ran perfectly for 10 years, until our neighbour complained about the 'gas smell'. The Bosch designated plumber arrived and after testing the unit found the PCB board had failed and it would be cheaper to replace it with a new unit rather than repair the old. The new and improved unit was all over the place with its heating, going from scalding to cold when ever you tried to adjust it. The worst situation is in the shower as you have to jump in and out to stop getting burnt or frozen. We persevered through about six months and could not cope anymore. We were using twice as much gas and water as before because we spent more time out of the shower than in it! So the plumber came back and ran all the tests that Bosch was telling him to do, Verdict, nothing wrong but they will send a replacement unit. Great we thought, but NO exactly the same faults. Bosch told the plumber that something must be wrong with the gas supply, the water supply and too install a new gas line. So now we wait for the plumber to return and fit a new gas line and if that doesn't solve the problem then Bosch will take the unit back and refund our money. Funny that the old unit ran for years on the gas supply. The plumber said that too achieve the efficiency rating the water is just trickling through the heater to start with and that may be one of the problems. As we have seen with some German companies lately, they haven't been quite truthful about their products performances ( Mercedes, Volkswagen Audi etc.)

Date PurchasedJun 2018
1 comment
Thank you for taking the time to write your review. We truly appreciate your feedback and we are so sorry to hear about your experience. Unfortunately, we do require further information to assist you. Please fill out our Contact Form found on: https://www.bosch-climate.com.au/about-bosch/contact-us/. Under ‘Comment’, please copy in a link to your review. Once we receive your information, we’ll be able to get in contact with you within a business day. Alternatively, you can contact us at our toll-free number 1300 30 70 38 any time between 8am to 6pm (AEST) during the weekday.

This product is a waste of time money and water

Brand new unit in brand new home and initially sporadic unreliable hot water until today - no hot water at all. Bosch contacted local service company who did respond. Friday afternoon facing the prospect of no hot water at all for the weekend. More than happy to have it replaced with a reliable non Bluetooth enabled system

Date PurchasedAug 2018
1 comment
Hi Chris, Thanks for taking the time to write your review. Please be advised that a Bosch service agent will get in touch with you regarding your issue. For any further issues, please don’t hesitate to get in touch with us at our toll-free line 1300 30 70 37 any time from 8am to 6pm during the weekday.

Don’t buy this unit. Try Rinnai instead

We bought this unit early 2018, plumber has been called twice the last 3 months, unit will not heat the water. Bought Bosch as it is a well known brand but in hindsight should of bought a Rinnai as our plumber has said that he has never encountered a problem with that brand

Date PurchasedMar 2018
1 comment
Hi Geoff, Thank you for taking the time to leave your review. We would recommend you get in contact with our helpful team at 1300 30 70 37 any time during the week from 8am to 6pm (AEST) for further assistance.

Something wrong with the temperature. Either too hot or too cold

Something wrong with the temperature. The company gave me a replacement and the problem still there.! The Bluetooth app sounds fancy but it is not working properly most of the time. I wouldn't recommend it as it is not reliable enough and didn't meet my requirements for the ststem. Thank you.

Date PurchasedJul 2017
1 comment
Hi John, thank you for taking the time to write your review and letting us know about the issues with your unit. As your unit is still under warranty, we would be able to book a service call for you. We’d also like to speak with you further regarding your Bluetooth issue and would appreciate it if you could contact us on 1300 30 70 37 any time from 8am to 6pm (AEST) during the week day. Please make sure to reference your issue with PRO16JOHN.

Failed 4 times replaced with brand new units 4 times within 6 months

Useless product, the unit has failed 4 times, all brand new unboxed units supplied and installed by Bosch Australia (ACT). After sales care is non existent, multiple calls to get a technician out. Replaced 4 times by so called experts and unit still failing. Buyer beware stay away from Bosch & Bosch retailers in the ACT region

Date PurchasedAug 2017
Hi Keso, Thank you for taking the time to leave your review – we appreciate your feedback and we are so sorry to hear about the issues you have been experiencing. We have looked into your specific experience in detail, and based on our understanding of the situation, a second new unit was installed yesterday which we trust will provide the fix. If however you have any further issues regarding this unit, please don’t hesitate to contact our team at 1300 30 70 37 Monday to Friday from 8am to 6pm (AEST). You can also always get in touch with us at hotwater.query@au.bosch.com.Product has failed again this morning 17th November 2018. Past history. Product was installed on the 25th of August 2017 Replaced by Bosch on 18th June 2018 Replaced by Bosch again on 27th July 2018 Replaced by Bosch again on 5th of August 2018 Keeps getting replaced by the same crap product which keeps on failing. Unreachable customer support over the weekends, out of pocket expenses running into the thousands. Ridiculous product. Ridiculous after sales support. No compensation. Absolute headache to deal with.5 Days and counting, still no repairers, no alternatives from bosch, no way forward, no hot water.

Biggest piece of trash I’ve ever bought

Replaced my old unit with an optiflow 20 professional and it packed up within months the tech guy has been and repaired it 3 times. The next time called out they replaced the unit. Not even a week later the new one has started playing up. I wish I could get my
Money back and buy a different brand. Not at all happy

Date PurchasedOct 2017

Don't waste your money.

Nothing but dramas with this unit! We had the first one replaced within 6 months even though we had drama with it from day one but plumber wanted nothing to do with it. Replaced all piping and regulator trying to fix it but found out there was a whole batch that were faulty and we had one of them! Bosch knew the whole time that we had a faulty one (they had the faulty batch serial number) and they never let us know. After calling the plumber and Bosch repeatedly we finally had it replaced. But still don't recommend even with the new unit. So much water gets wasted before it heats up. You can fill the kitchen sink to full before the water starts heating and you stand in a cold shower for a minute before it starts running warm which is great for the kids in winter!
Also, ours is run off bottled gas and we have had some major issues when one bottle runs out and we need to switch to a new one. Have had air locks in the pipes that are a nightmare to get out.
We purchased the extra temperature unit which you fit inside the house and it allows you to adjust the temperature, turn unit off and on and see any fault codes. In my opinion this should come with the unit considering how much it costs and shouldn't be an extra we have to pay for. Without it we wouldn't have been able to fix half the stuff ups this unit has had. Atleast we've had fault codes to refer to.
All in all: don't waste your money. Nothing but a headache!

Date PurchasedSep 2017

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Questions & Answers

Is the set temperature meant to flash non stop when the unit is heating the water or make a humming sound after the tap is turned off
1 answer
Hi Henry, the temperature flashing means the appliance is not delivering the set temperature. Once the unit is delivering the set temperature, it will stop flashing. The buzzing you hear after the tap is turned off is the water valve adjusting to optimal position for the next hot water usage. We hope this is helpful and if you have any further questions, please don't hesitate to contact our friendly team at 1300 30 70 37 any time during the weekday from 7:30am to 6pm (AEST).

My Bosch electronic high flow 25E (13 years old) has stopped working. What would be the best replacement?
1 answer
Hi Trudik, thank you for your question. The best replacement for your Electronic HighFlow 25E would be the OptiFlow 26L model. Please be advised the OptiFlow model is not suitable for tank boosting arrangements (that is, commercial boosting of warm water recirculation systems). If you need help finding an installer or have further questions, please contact us at 1300 30 70 37 any time from 8am to 6pm (AEDT) during the week.

Why has Bosch not recalled the Optiflow gas hot water system because it is doing the brand name considerable damage and costing its customers a fortune in having to buy reliable replacements?
1 answer
Because unless it's risk to life companies do not recall. If the unit you bought is NOT FIT FOR PURPOSE (delivering consistent flow and temp water) then under Consumer Law, the company needs to REPAIR or REPLACE or REFUND. If repair didn't work, they might suggest another repair (refuse) then they will either offer a replacement (within their rights) at their cost not tours, or refund. If you have already had a repair and a replacement and still do not have WHAT YOU PAID FOR (continuous flow and heated water) then put your foot down and scream REFUND. Also, losses (within reason) that you have incurred should be claimable, as long as they are directly caused by the unit not working, and as long as you have PROOF of those costs, but you may need to put your claim in legal terms and quote the legislation when putting in such a claim.

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