I have a shower over the bath which is fed via a water storage tank and pump through a Steibel hydraulic multipoint water heater. The shower is operated by a lever on the bath taps but it is only ever scalding or cold and never comfortable. Even after juggling the lever, the water could be hot enough for a minute then get scalding or cut out and get cold again.

anyone come across a similar problem? I was thinking of replacing the hydraulic heater with an instantaneous unit but not sure if it will resolve the issue. Also it is a rented house so I dont really want to buy a new unit

Looks like an "inventive" solution to me.

Inventive aka. stupid/botch job.

 

Feeding a mixer tap with such a water heater.

A first timer for me.

And quite certain it can not work.

If you move the mixer towards cold, the flow through the heater falls below a minimum and it switches off.

 

BUT: isn't there the easy solution to shift the mixer to "hot" and set the desired temp on the heater?

Or do I miss something?

Maybe you need a ladder to reach the temperature knob on the heater

 

24 minutes ago, ragabob said:

Even after juggling the lever, the water could be hot enough for a minute then get scalding or cut out and get cold again.

anyone come across a similar problem? I was thinking of replacing the hydraulic heater with an instantaneous unit but not sure if it will resolve the issue.

Every time I have encountered such units in Thailand have had the same issues - they just do not operate reliably here (probably due to the low/varying water pressures).  If this is only for the bath it would be easy to replace current unit and attach shower directly to new unit like below and when leave return the old unit to wall and keep the one you buy for next place.  

Looks like the mold will get you before the scalding hot water :)

If you mostly take showers, not baths, why not unscrew the discharge hose from the blue pvc connection leading down to the faucet/mixer, then attach it directly to the shower sprayer?  I may have circled the wrong one below - whichever is the discharge side - mine is water input on the left, discharge on the right.

 

May not solve all the hot/cold issue.  That could be exacerbated by a pressure pump cycling on and off during the shower. 

 

Pump on = colder water.  

Pump off = hotter water.

 

3 hours ago, 55Jay said:

why not unscrew the discharge hose from the blue pvc connection leading down to the faucet/mixer, then attach it directly to the shower sprayer?

Suspect water can not be adjusted to a non-scalding range if it is designed to be using mixed with cold water.  Water temp varies greatly (sun or rain) here as most stored above ground so point of use easy control needed.  This is what a normal shower unit provides.  And personally find manual control better than automatic temperature gage high priced units - both for easy control and reliability.  

Classy Thai bathroom.

The colour of that grout!

11 hours ago, KhunBENQ said:

Feeding a mixer tap with such a water heater.

A first timer for me.

And quite certain it can not work.

If you move the mixer towards cold, the flow through the heater falls below a minimum and it switches off.

 

BUT: isn't there the easy solution to shift the mixer to "hot" and set the desired temp on the heater?

My water heater is connected to a mixer tap in exactly the same way, but as you point out I simply dont use the cold flow at all and I set the desired temperature on the heater itself. Works fine.

 

However, I live in a high-rise condo with high and stable water pressure that never varies.

Kittenkong - grout is work in progress, same as mold.

lopburi3 as suggested I will proceed with a new unit then replace if and when I leave, thank you

Before you buy a new heater (the one you have appears to be working).

 

Have you tried running max hot on the taps and adjusting the heater?

 

Are there any gauze filters on the heater supply pipe and shower head? Are they clean?

 

You have a water pump? Is it working properly?

 

We have a similar arrangement (no bath) but our mixer is the type with two taps. In order to shower comfortably I turn on full hot then adjust the temperature by varying the cold (ok, cooler) tap.

5 hours ago, lopburi3 said:

Suspect water can not be adjusted to a non-scalding range if it is designed to be using mixed with cold water.  Water temp varies greatly (sun or rain) here as most stored above ground so point of use easy control needed.  This is what a normal shower unit provides.  And personally find manual control better than automatic temperature gage high priced units - both for easy control and reliability.  

OK, thanks.  

Admit not knowing what a "Hydraulic Multipoint" water heater is vs. the Instant type.

Had a bit of a similar problem with my shower (temperature not constant). Replaced the faucet with a Grohe thermostatic one bought in Europe. Problem solved, but I would have no idea where to buy these in Thailand....

4 hours ago, 55Jay said:

OK, thanks.  

Admit not knowing what a "Hydraulic Multipoint" water heater is vs. the Instant type.

It is an instant type, just triggered by water pressure and can supply more than 1 outlet, hence Multipoint 

http://www.stiebeleltronasia.com/index.php?op=faqs-index

Just do it Thai style: Fill a big bucket with water and mix hot and cold until you like it. And then take a bowl to splash the water from the big bucket over your body. Problem solved.

Just do it Thai style: Fill a big bucket with water and mix hot and cold until you like it. And then take a bowl to splash the water from the big bucket over your body. Problem solved.

Or leave 5 gallon pails in the sun during the winter and bathe midday like my mil, a village rice farmer.

I think he is having you on... you see these types of set ups on rough tradesmans websites really as a comedy show.

we don't have such rough tradesmen here in Chiang Mai

I contacted Stiebel and the Technician came today. It seems the hydraulic unit I have is adjustable between 2-4kw, 4-6kw or 6-8kw and is termed as a hot water shower rather than the instantaneous type. Mine was set at min 4kw and max 6kw. The dial on the unit face simply says min and max, which I took to being min temp or max temp.

The Tech reset to 2-4 kw and now I can have a comfortable shower and hopefully cope with the max setting of 4kw when the bitterly cold CM winter sets in.

thanks for all the comments.

i think I prefer the instantaneous where I can adjust between cold, medium, hot and inbetween.

2 hours ago, ragabob said:

i think I prefer the instantaneous where I can adjust between cold, medium, hot and inbetween.

Quote

There are two types of units from STIEBEL ELTRON: 

• Electronically controlled instantaneous water heaters
• Hydraulically controlled instantaneous water heaters

So you have an instantaneous water heater just not a continuously variable one.

i strongly suggest that if you get one of the normal continuously variable ones you get a minimum of a 6kw but probably an 8kw or you will be having very cool showers in the cold season