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Thermann Gas Continuous Flow

Thermann Gas Continuous Flow

5 Star, 6 Star and C7
3.1 from 21 reviews

Thermann 16

This unit is very efficient at delivering hot water within 15 Seconds.There is little water temperature fluctuation unless another person opens another tap.Overall i would say this unit is the best so far and would not go back to hydropower.

Purchased in December 2018 at Plumber for $800.00.

Build Quality
Value for Money
Cleaning & Maintenance
Noise Level
Household Size 4 person(s)
Smells of GasYes
Temperature Consistency
Heating Speed


Bought this heater on May 2018 by the plumber for a new house, moved in January 2019 when I noticed that the heater has a problem.
If you need to have a shower ask all the house occupants not to use the water in the house, otherways you will have a cold water shower.
called Reece for assistance, and the advice was to stop using the water in the house while anyone having a shower.
Now I have to buy a new hot water system because Reece says they can't help.

Purchased in May 2018 for $1,141.05.

Build Quality
Value for Money
Cleaning & Maintenance
Noise Level
Household Size 4 person(s)
Smells of GasNo
Temperature Consistency
Heating Speed


Installed this unit on recommendation of plumber who is a good man but obviously there is some sort of heavy promotion or leverage to get this happening. Have not had one shower in five months that hasnt gone cold at some point. Using flick mixer have to turn water to full hot wait two minutes then mix cold in and hope I can wash the shampoo out of my eyes without going cold again. My wife is ready to pull the fing thing off the wall and throw it on the plumbers front lawn. At 55 years old can honestly say worst purchase of my life!

Date PurchasedAug 2018

Very happy with this unit

One month in since I installed the Thermann 6* 16L and I'm very pleased. I only need to wait around 15-20sec to have a very hot water in the shower (@60C), I don't experience any water temp' fluctuation, and the water flow is steady.
the only reason I gave it 4*and not 5* is because you can't change the temperature without buying the R/C for an extra $100.(which I didn't buy)
Please note, the system is for serving two people with minimal use( showers and a bit in the kitchen ), the distance from the unit to the shower is around 8 meter, and to the kitchen is around 4 meter.
The installation was straightforward and cost $1100 including the unit.

Date PurchasedNov 2018

Absolutely crap.

Constant waste of water. From every outlet I have to wait ages for any hint of hot water with the cold turned off. The temperature also fluctuates still with the cold off. Sometimes it doesn’t even kick in and send hot water, I’ve had to go and turn the unit off and on again. Another waste of my money thanks to a plumber highly recommending it. Very very disappointed

Date PurchasedApr 2015

Agree wholeheartedly with Worst Item Ever

So much water is wasted to actually get hot water. Bought this thinking it would be more economical, stupid decision. Used to be able to have a 5 minute shower, now to get 5 minutes of water at a perfect temperature I am standing there for at least 25 minutes. Shower goes cold after about 3 minutes. No good just trying to adjust the hot water tap. Have to completely turn the shower off and start again - so again you're wasting litres of water to get hot water. Our gas bill is also now a lot more!

Date PurchasedFeb 2018

Thermann 6* 20L C/Flow 50DEG NG

Very pleased with the Thermann 6* 20L C/Flow 50DEG NG unit. The installation is for a small cottage with 1 bathroom. All kitchen , laundry and bathroom outlets within 14 feet of the heater. The install took about 5 hours and included the removal of the DUX electrical off-peak tank and changes to plumbing pipes in that area. I am new to the 50C hot water regulation, but the water seems hot enough to wash dishes in and the shower is comfortable to bath in and flow seems fine. I did have the water saver shower rose removed and a standard rose fitted to the shower, it is an 8 litre per minute WELS shower head. The all up cost was $2192.20 which included $220 for a level 2 electrician to remove the off peak meter from the meter box and $126.50 for the electrician to install the outside power point and terminate, in a block ,the off peak power line.

Date PurchasedAug 2018

Only want a good shower

I thought that it wasn't very good for the first two years, terribly bad pressure in the shower, good every where else, I had taken out shower head restrictor didn't seem to make any difference,, finally found another restrictor at the inlet, goodness two of them, my shower is now perfect

Date PurchasedMay 2016

Worst item ever

So much water is wasted to actually get hot water. Bought this thinking it would be more economical, stupid decision. Used to be able to have a 5 minute shower, now to get 5 minutes of water at a perfect temperature I am standing there for at least 25 minutes. Shower goes cold after about 3 minutes. No good just trying to adjust the hot water tap. Have to completely turn the shower off and start again - so again you're wasting litres of water to get hot water. Had an elderly relative stay who needs a shower chair, she had to bathe at the neighbours - she would either have 3rd degree burns or be frozen at our house. Continuous hot water - what's that?????

Date PurchasedJul 2017

Installed new Thernann 26 today. Less than impressed.

I just had a Thermann 26L/m continuous natural gas hot water unit installed today. My water pressure at the mains is 75psi before installation and I don't have any water saving heads in the home. So no problem with water pressure. When the plumber left and I got a chance to use it, I noticed it takes a good 30-45 seconds to go from cold water to luke warm and then rises to 50 degrees after a minute. My hand basin is on level ground less than 5m away. My kitchen about 10-12m away was worse. I turned the hot water on and had to wait over a minute before it got anything hotter than just luke warm. You would fill a kitchen sink full with wasted cold water before you get any hot water out. This is a complete waste of water.
The worst thing, is after you visit the toilet and go to your hand basin to wash your hands. You're washing in cold water for 10 seconds even before the unit has any sign of mildly heating up and then you stop the water. Say goodbye to washing hands in warm water on a cold winters day. This is a 1 bathroom house. I live alone. This has been a disappointing $3000 investment all up installed and connected to replace a 250L electric tank HWS including an updated circuit in my electrical powerbox.
I will not recommend this product at all. Over a minute to get mid to high 40's and then 50 degrees is abysmal. This product came 'highly recommended' by the Plumbing and Electrical Doctor. 'Everybody gets these units now and they are great' I was told. I actually read up and found the 26 sizing too excessive for my use and requested a 16 or 20, but again was told 'We recommend and only install 26's in every house now'. For such a highly praised company to highly praise this unit, one would expect a level of performance.
This morning I had a shower. The water took over a minute to get to temp. In the early stages of the shower it went warm and then luke warm, then warm again to hot. I maybe had to adjust it 3 times at first. But after it was running it had no problem supplying hot water.
The trade off with these units is wasted time and a lot of wasted water. Im in suburbia, but if you are on a rural property and have tank water, Do not buy this unit.

Date PurchasedMay 2018
1 comment
Winter update. End July 2018. I hate this water system! Soooooo much water is wasted passing through it. Now that its winter and ground pipe water temps from the street are very cold, expect to turn the tap on and wait for over a minute to get any warm water through. Go and time 90 seconds of water flow in your shower and see how much water is wasted! The kitchen sinks fill up with cold water before they even get luke warm. This product is a joke. Do not buy this product if saving water or living off tank water is important to you. That wasted water adds up. I dread going to the toilet and washing my hands in freezing cold water afterwards. Be smart. Look at another product.

Better than Rinnai

Just had a Thurmann 26 installed to replace our 10-year-old Rinnai. Heat exchanger in the Rinnai sprung a leak and it was not economical to replace and Rinnai one we're not interested even though it was just over 10 years old and out of warranty and 2. it was going to take them a week at least to get a servicemen to look at it. We had our Thurmman from All blocks Plumbing replaced within 2 days. The Thurmman has a great warranty and the best bit is you don't need to call the company to get their service agent out to look at it, the plumber who installed it is the service agent. My only little gripe is, it does seem to have an audible beep coming from the unit and I cannot find any information on it whatsoever...so Thurmman if ya listening...what is it? (ps no remotes connected)

Date PurchasedMay 2018

Excellent product.

We had one of these installed about six months ago. The hot water temperature is perfect. The plumber recommended this system and it has been a great choice. Would highly recommend one of these continuous hot water systems. It is much cheaper to run than the old electric hot water service.

Date PurchasedSep 2017

Research required prior to product selection

I made an impulsive decision to replace a 25 year old electric storage hot water system with new Thermann gas continuous flow hot water unit. Didn’t bother to research the options and relied entirely on my Plumber whose advice I normally value.
A major downfall with the Thermann unit is one which, from other product reviews, I should have realised prior to its purchase. Whilst the Thermann unit adequately provides continuous hot water for use in kitchen and laundary, it cannot be relied upon to supply continuous hot water to a shower without turning cold for no apparent reason.
With regard to a cost comparison between electric vs gas, in theory gas should be more economical but due the heating process causing huge delay in delivery of hot water to the tap/showerhead there is probably no substantial cost difference.

Date PurchasedAug 2017

Very Unhappy

The Thermann 26 requires a a large volume of water to make it work so it won't work with water saving shower heads which is quite unbelievable in this day & age. It is not possible to close the hot water tap much to reduce flow & temperature as the gas cuts out, as it does if you turn the cold up much. As it is heating a large volume of water all the time to what I consider too high a temperature then it must by definition be using a lot of gas which is borne out by the fact that we now have VERY large gas bills and in a home with only two people and with very little gas used for anything else. Upon investigation with the distributor it seems that the temperature is not adjustable despite the instructions stating that it can be changed by resetting the dip switches. The instructions fib it seems. It is the worst piece of equipment I have purchased for a long time.

Date PurchasedAug 2015


So our we replaced our old gas water heater, Tank type. This Thermann produces a lot of hot water, fantastic. Problem is you cannot use water saving shower heads, need the waterflow to be high in order to get consistent water temperature. The worst part for us, is the exhaust gasses (Carbon monoxide) will fill the shed and or gazebo so you have to vacate these areas until the gasses disappate. So now I have been informed that my options are to relocate the hot water water system (and plumbing) or get a an additional flume to discharge the gasses above the roof line of the house which will hopefully prevent the gasses filling the gazebo or shed.

Date PurchasedSep 2017

Its hot! & water keeps coming.

I purchased the model Thermann GCF 26 6 star Model when the 320 Litre solar powered gave up in 3 plus few months. I am glad I purchased this unit. Had I repaired other unit it was on its last leg with corrosion on the bottom of the water tank. This unit was recommended by the installing plumber. Did some research on this forum & forked out $1100 for the unit.
Pros. Works well. We are 3 people family unit & we tend to take quick showers even with a teen in the house. Takes about 30-40 seconds on coldest days to get the hot water going. There's no boiled water or like constant boiled hot water tank which saves a bundle specially at night when it constantly get be in the 60c temps.
According to packaging this was made in Japan. Not many come electronics come from that region, perhaps better quality.
Cons: There's no tank so you have to wait till the heater element to get kick started. If some one has taken prior shower I find the hot water flow to be quicker. The first person in the morning will have to wait the longest to get the hot water going as the burner has to get it going & the water has to travel through pipes. I normally let the mixer turn to hot & leave it for few seconds. I also noticed if you stop the shower to do your body wash/ shampoo lathering, the hot water flow quickly disappears leaving with you with cold water flow. I am not sure if its easier to leave the hot water running wasting water which will give you hot water flow. I am ok with turning it off & waiting for another 20 30 seconds to get the hot water going. We live in an age of impatience where waiting for hot water for 1 minute becomes painful, then I think of all the people in remotes parts of the world who do not have any running water. Then it becomes lot more to enjoy that hot shower.
Its only been a month with the unit. I did check with the company they said it has 12 yr warranty, in reality I am sure it will be part to break with in 3 yrs thats not covered under warranty.

Date PurchasedAug 2017

What a difference

With electricity prices going through the roof, I recently made the decision to dump electricity in favour of gas. Being rural, I had to increase the size of the line from my LPG tanks to carry the larger gas flow so that the two showers in my home could be used at the same time. The install was made quickly and the over large electric storage tank was removed (so much more space now). I am more than happy with the results and the continuous hot water never runs out (unless the LPG tank does).
I have waited several months to write this review so that I could receive a new electricity bill using just the gas system. I can now say that even with the increased gas usage (and consequent charges), I am making a fair saving over the excessive electrical system I used to have.
If you are thinking of moving away from electricity, this is a good option.

Date PurchasedAug 2016

Thermann Gas Continuous Flow Hot Water.

I had this unit installed to replace the useless Chromagen Solar Hot water system. The Thermann unit I had installed by Diamond Valley Plumbing is the 26L 6 star unit which is preset at 60deg. The water heats very quickly and is continuous without any disruption. The unit comes with a 12 year warranty for peace of mind also. Leaves the old Chromegan system for dead and no stupid oversize storage tank taking up space.

Date PurchasedDec 2016

Thermann Gas Continuous Flow

I have no complaints and my gas bill has gone down by half since I had it. I did have the same issue of the hot water cutting out which is caused by the water saving shower head. I fixed it by drilling a slightly bigger hole in the re-stricter washer located in the shower head. The reason I bought a Thermann is because the Housing Trust are installing them in there houses in my area. If you only have one shower then get the 16L, any bigger and you are just wasting more gas to heat the same amount of water.

This is a waste of money

Water temperature does not stay consistent temperature, can not have a Luke warm shower on the hot night without it going cold, water pressure for a normal has to strong terrible gas hot water system. It is extremely good on gas too bad you can't say the same about the show

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Questions & Answers

I just had installed the Thermann 26 GCF. Heater . So far no complaints. Can you suggest a backup power supply option for the ignition were there is a power blackout ? Last year we endured 3 days without power. So a backup option would be nice. Cheers.
2 answers
Rip the whole thing off the wall and chuck it in a skip waste of moneydo not spend any money, not worth it.

Can a natural gas Thermal 20 be converted LP gas?
No answers

I'm doing a new build and I'm thinking of looking at installing a Thermann C7. Who does their warranty service work if I buy it through Reece. I have heard that if there is a problem with them that they replace them but not service them onsite. Is this true?
No answers

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