Small Kitchen Water Heater

[fremmel]

I'd like to install an undercounter, tankless water heater that only services the kitchen sink through a mixing valve. Ideally I'm looking for something around 2.5 to 3 KW but all the units I've found in that range have a pressure switch and are designed for shower use with the valve before the heater. The units I've found with a flow switch are at least 6 KW. I don't want to use one this large because, aside from the expense, to get enough flow to turn the unit on means the water will be too hot unless you turn the water full on and maybe too hot even then.

Has anyone seen a smaller flow switched unit in Thailand?

[wimpy]

I don't think they exist. I have been using a small tank type Fagor for about 4 years now, which I have bee quite pleased with. The guys at HomePro told me it would be more economical to run than the tankless type. Don't know if that is true or not.

[Crossy]

This is ours:-

Bought about 12 months ago to replace its predecessor that went pop, don't remember the price though.

[fremmel]

Wimpy, a tank type would be nice for the temperature control but I hate to give up the space and the ones I've seen were pretty pricey. Is there anywhere that carries replacement heating elements for when it goes or do you just have to chuck it and buy a new one?

Crossy, that looks like just the thing I'm looking for but I can't quite make out the model number. Is it DH-JFT2? I Googled Panasonic but can't find anything for that heater. Just to make sure we're on the same page here - the sticker in the upper right corner says it's a shower heater but you're using it with a mixing valve connected after the heater, is that right?

[wimpy]

Wimpy, a tank type would be nice for the temperature control but I hate to give up the space and the ones I've seen were pretty pricey. Is there anywhere that carries replacement heating elements for when it goes or do you just have to chuck it and buy a new one?

Crossy, that looks like just the thing I'm looking for but I can't quite make out the model number. Is it DH-JFT2? I Googled Panasonic but can't find anything for that heater. Just to make sure we're on the same page here - the sticker in the upper right corner says it's a shower heater but you're using it with a mixing valve connected after the heater, is that right?

Good question. Hopefully replacements are available when the time comes. I don't think the heater Crossy is using is supposed to be hooked up that way.

[Crossy]

Wimpy, a tank type would be nice for the temperature control but I hate to give up the space and the ones I've seen were pretty pricey. Is there anywhere that carries replacement heating elements for when it goes or do you just have to chuck it and buy a new one?

Crossy, that looks like just the thing I'm looking for but I can't quite make out the model number. Is it DH-JFT2? I Googled Panasonic but can't find anything for that heater. Just to make sure we're on the same page here - the sticker in the upper right corner says it's a shower heater but you're using it with a mixing valve connected after the heater, is that right?

Good question. Hopefully replacements are available when the time comes. I don't think the heater Crossy is using is supposed to be hooked up that way.

Whilst it does indeed say shower heater, it is correctly vented and goes to regular taps and shower mixer i.e. it is supposed to be hooked up like it is . I can't find it on the pansonic site either (I wanted to check the power rating).

Had a quick look in HomePro, there are a fair few multipoint heaters (that's the type with the tap after the heater) available for 5-6k Baht.

[fremmel]

Thanks for the confirmation. I haven't had any trouble finding multipoint heaters - just small multipoints. Since it says it's a shower heater how did you find out you could put a tap after it? When I've looked inside the heaters I've had a hard time deciding whether it was a flow switch or a pressure switch so I just assume it's a pressure switch if it says "shower". By "it is correctly vented" are you talking about a pressure relief valve in case the thermostat fails or the switch sticks on? Is so, where does that vent too? I didn't see a separate hose for that.

Since you found a Panasonic I'll start looking closer at them. I don't really trust the salesmen so I guess I'll just start looking through the manuals, if they have them for the display models, and see if I can find one that shows the valve being being installed after the heater.

[wimpy]

Whilst it does indeed say shower heater, it is correctly vented and goes to regular taps and shower mixer i.e. it is supposed to be hooked up like it is . I can't find it on the pansonic site either (I wanted to check the power rating).

Had a quick look in HomePro, there are a fair few multipoint heaters (that's the type with the tap after the heater) available for 5-6k Baht.

You may be right, but normally the units that are designed to be connected to a faucet look something like this...

They don't typically have a big on-off button (like yours) designed to be used while taking a shower.

[torrenova]

I put in one of these Panasonic 10kw multipoint heaters http://www.panasonic.co.th/web/Pid/2390 but they have a whole range here http://www.panasonic.co.th/web/productssol...es/showersystem and some details from Numchai http://www.numchai.com/ecomm/store/index.p...mp;filter_id=26

You could use Steibel Eltron as well.

Though I have a 10kw system (3 power settings though), there is no issue with it being too hot. I just run it through a number of mixer taps. Where the lever is positioned for the same outward temperature depends upon the temperature of the inward water.

[powderpuff]

The 40 amps that draws will need custom wiring back to load center.

I like Steibel; good brand.

[Crossy]

The 40 amps that draws will need custom wiring back to load center.

I like Steibel; good brand.

All water heaters (tankless or storage) should have dedicated circuits with RCD protection.

Agree with Steibel

[david96]

Have you considered a storage HWS 45L/ 1.8kW they are fitted with a pressure relief valve,

thermostat and over temperature cut out. These will fit under a benchtop and are a far more viable alternative than a 10kW instantaneous water heater.

Instantaneous water heaters have their place in a commercial or industrial environment but not in a domestic situation. Small shower heaters single phase 20A and under are the exception.

Unfortunately Thailand does not appear to have off peak water heating tariffs, if they did it would be the end of instantaneous water heaters for domestic use.

A downside to instantaneous water heaters is their large current requirements 6 to 10kW.

10kW is 45.4A at 220V. Heavy loads on a distribution system and its effects on other consumers.

Other alternatives are solar HWS for 270L units or LPG for water heating.

[david96]

Some may question my logic in a previous post regarding high current instantaneous water heaters but here it is.

1. Most domestic/residential electrical installations are single phase.

2. The connected load is still the FL Amps of the unit.

3. If one was to install a high current unit on single phase upgrading of the consumers mains

may be required.

4. If you choose to install a high current unit eg a 6 to 10kW unit and connect it 3 phase, one would have to upgrade the consumers mains, metering and main switchboard. Is that worth while economic expense when other options are available?

5. Storage systems can be switched on a time switch to heat only at off peak periods eg at night.

However, small instantaneous systems may be preferable in apartments and individual condos. However one requires good water pressure for them to operate satisfactorily.

Wall mounted gas systems may be available and they may suit your requirements better.

[fremmel]

Thanks for the replies.

WRT the multipoint tankless units in the 6 KW and up range, I'm avoiding those for a couple of reasons. I'm concerned that the flow of water required to turn on the heater will be too high when I only want warm water and I'll end up with just having hot water or cold water. Torrenova's 10 KW unit with multiple power settings would work but that ties into my other objection. I don't really want to spend 6 to 10 thousand baht or more just for hot water in the kitchen. As far as David98's point about power requirements, if I do end up going that way I'm OK. I've got a 100 amp CU with plenty of capacity on my feed.

The tank based systems would work well for my water temperature issues but they take up too much space. I found the 15 liter model at Homepro that Wimpy was talking about and another model at Global. But they'd be a real hassle to try to fit under the counter and they're also 6K baht and up. By the way Wimpy, Homepro said they could order the element which might be a good idea since you've had yours for 4 years.

I do like the gas fired units. In fact I've got one for the shower. But putting one in the kitchen would create major problems trying to venting it.

I found the unit that Crossy has, or at least I think it's the same. A Panasonic DH-3FT2. But the manual specifically says not to connect a valve after the unit. It's working for Crossy but pump has a cutoff pressure of 55 psi and I'm a little concerned that it might not work properly for me at that pressure. Besides, I found a cheaper way to go.

While at Homepro I ran into a tankless unit that was only 4.5 KW. I guess the sales people were bored because they hooked it up for me to show that it will turn on at a low flow rate. Their pump started cutting out before they could turn the water down as far as I wanted but it looks like it will work. And it's on sale for 3,200+ baht so I think I'll go with that.

Which leads me to another question. When I built the house I put in a dedicated circuit for a heater but I only ran a 2.5mm 20 amp circuit because I didn't do my homework and thought I could find a 3 KW unit. At 4.5 KW that unit's just a smidge above the 20 amp rating. I'm inclined to just go ahead and hook it up and see if the breaker pops before I go to the trouble of pulling a 4mm cable and putting in a 32 amp breaker. Am I endangering life and limb?

[bkkbill]

david96 all good points but the OP was not looking for something in the 6-10KW range he posted a range of 2.5 to 3 KW also did not wanted a small low cost unit.

Here are some advantages to on-demand water heating:

Tankless water heaters are compact in size and virtually eliminate standby losses - energy wasted when hot water cools down in long pipes or while it's sitting in the storage tank.

By providing warm water immediately where it's used, tankless water heaters waste less water. People don't need to let the water run as they wait for warm water to reach a remote faucet.

A tankless water heater can provide unlimited hot water as long as it is operating within its capacity.

Equipment life may be longer than tank-type heaters because they are less subject to corrosion.

Expected life of tankless water heaters is 20 years, compared to 10 to 15 years for tank-type water heaters.

Storage tanks at times require the installation of extra piping.

[powderpuff]

The 40 amps that draws will need custom wiring back to load center.

All water heaters (tankless or storage) should have dedicated circuits with RCD protection.

Went shopping for RCCB today - like this. Will be buying Siemens RCCB tomorrow. 1500 baht. Will post actual picture.

Edited December 23, 2009 by powderpuff

[david96]

Quote from post #14

Which leads me to another question. When I built the house I put in a dedicated circuit for a heater but I only ran a 2.5mm 20 amp circuit because I didn't do my homework and thought I could find a 3 KW unit. At 4.5 KW that unit's just a smidge above the 20 amp rating. I'm inclined to just go ahead and hook it up and see if the breaker pops before I go to the trouble of pulling a 4mm cable and putting in a 32 amp breaker. Am I endangering life and limb?

No, you will not have undue temp rise in the cable. The MCB will not trip.

2.5sqmm will carry 25A in free air or 20 A enclosed. Your heater will not be operating on a continuous basis. Only on demand when required. If it is a long cable run it might pay to check the voltage drop on the circuit.

[fremmel]

Thanks, the 2.5 mm is VAF-GRD in conduit but it's only about a 10 meter run.

[powderpuff]

Thanks Crossy. Total price for 2 items 1585 baht from my local supply store (opposite the traffic light at Suk 62).

To the OP. You clearly need a multi-point heater; you say you already have the mixer.

[fremmel]

Just a quick followup. A couple of days ago I went ahead and bought the 4.5 KW unit - a Clarte model SHM-45 for 3,290 baht. I installed it today and it's working well. The water's hot when full on but I can turn the water down to a reasonably low volume and still get warm water.

If anyone else is looking for something like this now would be a good time to get it. It's on sale at Homepro until the end of December. Then it goes back to around 6,000 baht.

[torrenova]

Just a quick followup. A couple of days ago I went ahead and bought the 4.5 KW unit - a Clarte model SHM-45 for 3,290 baht. I installed it today and it's working well. The water's hot when full on but I can turn the water down to a reasonably low volume and still get warm water.

If anyone else is looking for something like this now would be a good time to get it. It's on sale at Homepro until the end of December. Then it goes back to around 6,000 baht.

Are you saying that you can't have the tap on full because the water is too hot ? and have to turn the flow rate down to get water of a manageable temperature or are you saying that you can get hot water from low to full flow rates ?

[fremmel]

The latter, I can get good hot water from low to full flow rates. But, and this is what I was originally worried about, I can also get water that's just warm from reasonably low to full flow rates. I've had trouble before in rental houses with multipoint units that as you turned the water to warm there wasn't enough water going through the heater to keep it turned on unless you turned the water full on. So at low flow rates you could have either hot water or cold water, but not warm water. But that isn't a problem with this unit. If I turn the volume too low the unit will cut off, of course, but the cut off volume is low enough that it's not a problem.

So, I'm happy. I can not only have hot water but also water that's just pleasantly warm without having to turn it on so hard water's splashing everywhere.

[chantorn]

This is ours:-

Bought about 12 months ago to replace its predecessor that went pop, don't remember the price though.

This is a shower heater. You should not put a tap after this unit.

Although it will work in the short term, I will break down soon.

For hot water heater, Panasonic only have 1 model PANASONIC DH-6GM1T

3 setting, L/M/H; 2.5, 3.5 & 6 kw

[Crossy]

This is ours:-

Bought about 12 months ago to replace its predecessor that went pop, don't remember the price though.

This is a shower heater. You should not put a tap after this unit.

Although it will work in the short term, I will break down soon.

For hot water heater, Panasonic only have 1 model PANASONIC DH-6GM1T

3 setting, L/M/H; 2.5, 3.5 & 6 kw

That was my thought when the man installed it, but note it has a pre-set flow control on the inlet rather than the more usual regular tap that you would find on an unvented heater. It is definitely flow controlled rather than pressure controlled (as a shower heater would be) and it's still working just fine after 2 years. I'm not worried, it belongs to the landlord if it goes pop.