Is it, will try it out first, if i feels like complicated then let the expert do it

It means that your original water pressure (without the water heater's built-in pump) is already strong, close or even surpassing what the water heater's built-in pump can generate.

Note that regardless of whichever water heater brands u purchase, water heaters' built-in pumps are way smaller in comparison with the lights of external booster pumps, such as those Grundfos (https://s.shopee.com.my/BDMfj7nW6) or Tsunami (https://s.shopee.com.my/1B6Sj91TNJ) which cost way more as well and way more powerful.

So for example, if your house has one of these external booster pumps installed at your main water supply, u will not feel any difference between turning on and off your water heater's built-in pump during showers.

Good points. If house already have a central pump like Grundfos, don't need to buy water heater with pump... waste money.

In fact if the water pressure is very high, need to turn down the flow else the water won't heat up enough.

Ya, it's better to have the pros do it especially all the wiring etc

Certain diy im very good, but certain things need someone expert to do it

For safety reasons better have experience pros do it. Risky to diy

True ☀️🔥☀️🔥☀️🔥☀️

Correct. Similar reasons why external booster pumps (or basically houses / condos with high water pressure) are normally paired with storage water heaters (example here - https://s.shopee.com.my/9zhBPf4sNC) rather than instant water heaters, since storage water heaters can generate much hotter water.

Higher water pressure / water flow equals to lesser contact time between incoming water and the instant water heaters' heating element, hence lesser heating which then equals to lower output water temperature for instant water heaters. Hence like what u say, if the water pressure is higher than average, then regular instant water heaters won't be powerful enough to heat up the incoming water.

Anyone has experience water is very hot even temperature knob at lowest setting? Incoming water is cold as i can feel from basin. Having 4 ruxine heaters. 3 of them like this condition.. After sales sucks

I am assuming you are referring to instant water heaters, not storage water heaters, correct?

Firstly, all SIRIM certified common instant water heaters should have a thermostat to turn off the water heaters if the output water temperature exceed around 50°C to 55°C, and very seldom this thermostat will malfunction.

Next, the instant water heater's output water temperature is affected by:
1. Inlet water temperature | The lower the original water source's temperature, the lower the output water temperature.
2. Power rating | The higher it is, the hotter the output water temperature (but higher electrical components' specs required).
3. Water flow | The higher it is, the lower the output water temperature.

The most logical possibility is that your water flow is very low (but still sufficient to turn on your water heater's flow switch), but your output water temperature is still not high enough to trigger the thermostat to turn off the water heater.

Also, test the water heater's input water supply to see if it is originally hot or not, as maybe for some reason it is using a water source different from your basin (eg. directly from your water tank that is under the hot sun for the longest time). This test is easy to perform, just quickly do it to rule out this possibility.

Just to share.

10 years, 2 Joven booster pump heater (one was DC, recently AC pump) failed, so i decided to move out from Joven brand and install a Panasonic DH-3NDP1MS last week, no regret on it so far. Bought at Shopee for RM650.

I install the heater myself, compare the internal built with Joven, i'm very surprise Panasonic at the similar price gave a much robust and better quality built, copper heater tank, silent DC pump, and the old school but trusted push rod ELCB. Furthermore the Panasonic model come with digital LCD and temp control, means if you set 37'C, it will auto regulate the water temp at 37'C based on different water flow as long as it is stay within 3600W max power (can see the bar that indicate power level), so you won't get sudden hot water when someone open tap water in another room causing water pressure to drop, or no need to adjust the water temp during noon and night due to different inlet water temp.

The Joven AC pump model that failed recently (temperature control failure, always stuck at max temp), upon open up a thick layer of black carbon powder from the AC pump carbon brush scattered all over the place inside the casing and board, this is extremely danagerous as the carbon dust is conductive, this show how poor the Joven engineer design in terms of safety aspect of the heater.

I think Panasonic latest design is catch up with what Joven/Rinnai/Alpha offer in terms of appearance, i don't think i will go back to any non Panasonic water heater in near future.

This post has been edited by coolkwc: Mar 25 2025, 11:13 PM

I have this model (non rain shower), forget about the built in pump from water heater, be it AC or DC pump, especially DC pump is slightly weaker compare to AC pump. You will need a powerful external booster pump if you primarily using rain shower. I do have a 0.5Hp booster pump installed with aftermarket rain shower pair with the Panasonic heater.

If you ask me, and chiefly speaking about root-analysis, to anyone who is wondering, water heater / hot water system don't really matter much from one brand to another.

This is because the technology that is designed to generate the pressure and heat has been centuries old ---- since the law of its very own physics founding itself until now, which is really a mature and stable technology. Primarily, the pressurization aspect, and likely the heating contraption also.

It hasn't changed, because, it's proven ---- cost-wise, and logically functional and explainable. And moreover, it's fruitless to spin the wheel and reinventing the exit.

Mechanical engineers would know that brands don't matter much. Better yet, they already know a cheap China-made pump works well enough for them.

What you need to know however, is the material usage behind the water heater or hot water system, and any patent for the unique selling point of the product you're eying on-----usually to protect the electrical component to keep it from destruction, while the material usage is what helps water heater pump resist against thermal radiation / expansion / contraction / wear and tear / thermodynamics.

These days, individual household products are well-fitted with micro pump technology and you see this in car jet washing, to fish tanks, drinking filter, etc, and you get the same physics application but in different sizes. Because there is more money to be made fitting into micro segments.

Hope it helps.

I'm quite interested to get the Centon Neptune 30 to replace my suspected faulty/leaking Joven, which I'm not sure is how old already. The model is Joven JH25 with 25 litre capacity.

Are the corrossion and rust due to water leaking? Seems like the plastic or outer material is cracking/crumbling already.

I take daily showers around the same time (night) but water is already warm even when I don't switch on the water heater. Maybe the continuous leaking cause the water to continuously warm up and that explains my unreasonably high electricity bills all these years?

Could sifu Selene Yeo shed some light?

Joven's new JHS25 HE apparently has up to 20% energy savings but I'm not sure if I really wanna get another Joven

Even though the household only does 1 hour of showers daily, I don't think I would like to go for instant water heaters as the shower pressure is pretty good around 35 litres/minute which no instant water heater can come close to (I think most are max 10litres per minute only).




This post has been edited by -kytz-: Apr 2 2025, 02:35 AM

Based on your picture, it does look like leaking. The only way to confirm is to get a JOVEN technician to verify. If it is really leaking, it is usually close to impossible to repair, and more cost worthy to just get a new one.

With my limited info, I believe currently there are 2 types of storage water heater tank technology available in Malaysia,
a. Enamel-coated tank technology - newer technology, better leak resistance, and cheaper. CENTON and ALPHA brands are using this new technology.
b. Stainless-steel tank technology - old technology, more prone to leaking, and more expensive. JOVEN and ELTON brands are using this old technology.

For your new one, I suggest u to get one with the enamel-coated tank technology, hence better leak resistance compared to your current JOVEN one that uses the old stainless steel tank technology. CENTON is a good choice, as if u do a quick search on Shopee / Lazada, this CENTON storage water heater (link here) looks like the best storage water heater on Shopee with the highest sold count and with the most 5 star reviews as compared with other brands. U can read the reviews to make an educated decision on whether to proceed with your purchase or not.

Just a heads up too, there's a few noticeable issues with your current installation:
1. U didn't install Isolation Barriers at both inlet / outlet, compulsory as per the Suruhanjaya Tenaga guideline (screenshot below), increasing the risk of being electrocuted.
2. U didn't connect a discharge pipe to your Pressure Relief Valve. Water (and possibly hot water) might get discharge from the Pressure Relief Valve when there's abnormal high pressure spike, and will flow out directly below it, damaging the ceiling directly below it / endangering anyone below.




I believe all storage water heaters, regardless of brands have sufficient insulation to keep the water in the tank hot throughout the day, like a thermoflask (eg. when u heat it up in the morning, if it is unused, it should still be hot enough for shower at night with minimal heat loss thanks to the insulation). This shouldn't be the cause of the leaking.

All SIRIM certified storage water heaters also should have thermostats that will auto cut off the heating (electricity usage) when the water in the tank reaches a certain maximum temperature and it will auto on back to heat up the water when the temperature drops to a certain minimum temperature (via heat loss over time). Hence, storage water heaters will not continuously heat the water even if u keep the switch on, and no harm just keeping the switch on, unless you are away for holidays. Storage water heaters' electricity usage will definitely be higher than instant water heaters, since their output water temperature is wayyy higher (laws of thermodynamics), but I don't think it will be drastic enough to affect your electricity bills as compared to appliances like fridges or aircons.


IMHO all these energy savings are just plain marketing / nice to hear. Heating technology are already quite mature for the past decades (as mentioned above by @Hastebreak), and I believe no one has actually did a proper test to verify these marketing claims. What should matter more is the tank technology and the likelihood of leakage, as shared above.

This post has been edited by Selene Yeo: Apr 2 2025, 11:27 AM

Thank you so much!

Just wondering if you have a recommendation for an installer? Really don't want the same installation mistakes with the current water heater which was already here when I moved in.

And yeah I'm set on the Centon

Usually I'll just ask the Shopee / Lazada sellers I purchased from to recommend me an installer. The Shopee seller from the link I shared earlier (here) should be able to recommend u one, with such a good sales volume I expect experience sellers like these to have some installers' contacts.

Just curious, do u know if your JOVEN storage water heater that was installed without the Isolation Barriers was provided by the developer, or it was installed by the previous owner? If it was provided by the developer, then that's quite bad, as the same installation mistakes may occur for the whole township / condo units as well. Best to give your neighbors a heads up if that's the case.



This post has been edited by Selene Yeo: Apr 3 2025, 12:13 AM

used Panasonic about 10yrs + .. now changed to JOVEN, because the supplier / service centre nearby my house, and the old Panasonic had leakage, but parts expensive .. so migrated to JOVEN, after few years there's once the input heater sensor had problem, straight went bought the sensor at the service centre and changed it myself .. done!

the sensor just costed RM15 each .. I bought 2 sensors incase to use in future

both Panasonic & JOVEN came without pump feature because my house the water pressure is high ..

Thanks. Installation charges RM400-450 is considered normal? Extra RM100 to remove old water storage heater.

I just checked, apparently it was installed by the developer but tbh, cant say for sure if it was meddled by other electrician/plumbers over 20 years. But i really appreciate you pointing out the big safety concern.

I think my other bathroom heater is probably installed the same way too

Not too sure what's the market price for storage water heaters' installation, but it is definitely expensive (sometimes even close to the price of the storage water heater itself), as storage water heaters are very heavy and sometimes multiple installers are required for larger capacity ones, plus the risk of injury due to the installation height and the appliance's weight.

I know people who had opt for way cheaper installers (eg. unlicensed foreigners), which ended up badly regretting their decision as similar wrong installations like your current storage water heaters may occur, some even damaging their storage water heaters beyond repair even before using for the 1st time (such as installing it in an inversed direction, or turning on the switch before water fill the tank, both causing dry burn in the tank due to the heating element heating air rather than water).

IMHO, don't cheap out on high risk appliances' installation cost.


Best to get it checked and fixed if unsure.