I have an under the sink shower heater , 10 years old but still running strong however from the first day of installment adjusting the right temp was a problem

 

the guy who installed told me I needed a much larger shower head and that actually worked but the head died from to much grit build up.

 

Bought another approx the same size I think..(threw the old one out ,should have measured it) any way water temp is piping hot and adjusting the hot cold lever will cool the water until its right in the middle ( still a bit to hot) . Anywhere past the middle and the hot water completely disappears.

 

whats up with that? water pressure is very strong

Anyone help me on this?

Just a guess, is the water supply for the hot and cold the from the same source?  the same pressure?

 

A differential in pressure between the two supplies would cause the sort of problem you describe.

 

 

11 hours ago, InMyShadow said:

Bought another approx the same size I think..(threw the old one out ,should have measured it) any way water temp is piping hot and adjusting the hot cold lever will cool the water until its right in the middle ( still a bit to hot) . Anywhere past the middle and the hot water completely disappears.

 

Not entirely sure from your description which levers/knobs you are talking about, but my water heater has a knob on it to adjust the temperature of the hot water. I just set that to the temperature I want for showering and only open the hot tap in the shower.

 

As for the shower head that you threw away, I could probably have been cleaned up. I find that the general cause of them blocking here is limescale rather than grit. A long soak in hot vinegar will dissolve the limescale. Or look for shower heads that have rubber jets as the limescale can be removed from these simply by rubbing your hand over the jets.

If your problem really is grit then perhaps a back-flush would help?

A photo or model number of the heater would be useful.

 

But as others note could be grit in the inlet filter of the heater restricting the water flow.

Most hot water heaters have a temperature dial and a dial to control the water flow.

The heater brand is fagor located deep under the sink . 

 

 

 

The tap hot cold mixer mixer is located on the bathtub tab

 

2 hours ago, KittenKong said:

 

Not entirely sure from your description which levers/knobs you are talking about, but my water heater has a knob on it to adjust the temperature of the hot water. I just set that to the temperature I want for showering and only open the hot tap in the shower.

 

As for the shower head that you threw away, I could probably have been cleaned up. I find that the general cause of them blocking here is limescale rather than grit. A long soak in hot vinegar will dissolve the limescale. Or look for shower heads that have rubber jets as the limescale can be removed from these simply by rubbing your hand over the jets.

If your problem really is grit then perhaps a back-flush would help?

The shower head is 6 months old so no grit in that . Whats a back flush? The water heater comes on automatically as soon as I turn the taps over the tub on. I then pull on a little knob the changes the flow to the shower

13 hours ago, Daffy D said:

Just a guess, is the water supply for the hot and cold the from the same source?  the same pressure?

 

A differential in pressure between the two supplies would cause the sort of problem you describe.

 

 

Not the same pressure, hot water is about 30% less

It's to do with flow rate. They aren't equal. The cold water exits your pump ( or the main supply ) at a given pressure and flow. it it split into two pipes. One goes to your heater, one directly to the shower mixer.  To effectively heat the water the heater has to reduce the incoming flow ( slowing the water's passage down enables effective heat transfer from the coils ) this means that there is less water arriving at your mixer from the "hot" pipe.

Only solution is to buy a more powerful heater that doesn't restrict the flow so much - even flow at both sides of the mixer. Or install a central water heater or solar. 

This is a common problem with heat at point heaters in Thailand. Nothing to do with the shower head.

 

And precisely the reason I have a solar heater and 3/4" supply pipes.

7 minutes ago, Pdaz said:

It's to do with flow rate. They aren't equal. The cold water exits your pump ( or the main supply ) at a given pressure and flow. it it split into two pipes. One goes to your heater, one directly to the shower mixer.  To effectively heat the water the heater has to reduce the incoming flow ( slowing the water's passage down enables effective heat transfer from the coils ) this means that there is less water arriving at your mixer from the "hot" pipe.

Only solution is to buy a more powerful heater that doesn't restrict the flow so much - even flow at both sides of the mixer. Or install a central water heater or solar. 

This is a common problem with heat at point heaters in Thailand. Nothing to do with the shower head.

Would it be better to buy a wall mounted heater next to the shower head rather than under the sink? strangely enough when the plumber installed it I had exactly the same problem and he said buy a large shower head and that fixed it so I could control the temp all the way.But the money Im wasting on shower heads now (2) I could have put towards a new heater (condo)

6 minutes ago, InMyShadow said:

Would it be better to buy a wall mounted heater next to the shower head rather than under the sink? strangely enough when the plumber installed it I had exactly the same problem and he said buy a large shower head and that fixed it so I could control the temp all the way.But the money Im wasting on shower heads now (2) I could have put towards a new heater (condo)

A wall mounted heater could improve your shower but there are downsides.

First you need to check the output of your current unit. How many watts is it rated at ?  If it is only a 3000-4000 watt unit you could buy a larger 6000-8000 watt under sink unit. If it is already a 6000 watt unit the only benefit of getting a new wall mounted one would be the shorter pipe run from the unit to the shower head - shorter pipe means less flow restriction.  There is a chance that your old unit is 'furred up" inside. Just like electric kettles hard water deposits build up and reduce the heaters efficiency over time. So replacing it may be the answer, especially if you were happy with it's performance a few years back.

2 minutes ago, Pdaz said:

A wall mounted heater could improve your shower but there are downsides.

First you need to check the output of your current unit. How many watts is it rated at ?  If it is only a 3000-4000 watt unit you could buy a larger 6000-8000 watt under sink unit. If it is already a 6000 watt unit the only benefit of getting a new wall mounted one would be the shorter pipe run from the unit to the shower head - shorter pipe means less flow restriction.  There is a chance that your old unit is 'furred up" inside. Just like electric kettles hard water deposits build up and reduce the heaters efficiency over time. So replacing it may be the answer, especially if you were happy with it's performance a few years back.

Ok thanks for the input . I will get the maintenance man here to remove it and have a look at the model wattage and inside the unit

I'm a bit at a loss at these replies.  40 years ago I bought a shower attachment with a dial that I could set the desired temperature to. It worked.

2 hours ago, Pdaz said:

A wall mounted heater could improve your shower but there are downsides.

First you need to check the output of your current unit. How many watts is it rated at ?  If it is only a 3000-4000 watt unit you could buy a larger 6000-8000 watt under sink unit. If it is already a 6000 watt unit the only benefit of getting a new wall mounted one would be the shorter pipe run from the unit to the shower head - shorter pipe means less flow restriction.  There is a chance that your old unit is 'furred up" inside. Just like electric kettles hard water deposits build up and reduce the heaters efficiency over time. So replacing it may be the answer, especially if you were happy with it's performance a few years back.

Just one more thing , The water temp flowing from the bath tap into the bath directly mixes hot n cold perfect, it only loses hot water pressure when "climbing " up to the shower head. Would this conform what your telling me? sorry Im not that technically minded

13 minutes ago, InMyShadow said:

Just one more thing , The water temp flowing from the bath tap into the bath directly mixes hot n cold perfect, it only loses hot water pressure when "climbing " up to the shower head. Would this conform what your telling me? sorry Im not that technically minded

If the water is being mixed perfectly at the bath mixer ( good temp, equal mix of hot.cold ) but you are only getting cold or warm from the shower head. Sounds like the showerhead . As the water should already be mixed before it arrives at the showerhead.

Is the showerhead or shower hose clogged ? can you remove the showerhead and see what the water flow/temp is like at the end of the shower hose. If it is the same flow/temp as what comes out of the bath mixer - The the shower head is your problem..

Another thought.. I'm guess you have to select which way the water goes using the bath mixer.. Either "down" to the bath or "up" to the shower.. Maybe it is the diverter valve in the mixer unit that is faulty - clogged or only opening partially. 

12 minutes ago, Pdaz said:

If the water is being mixed perfectly at the bath mixer ( good temp, equal mix of hot.cold ) but you are only getting cold or warm from the shower head. Sounds like the showerhead . As the water should already be mixed before it arrives at the showerhead.

Is the showerhead or shower hose clogged ? can you remove the showerhead and see what the water flow/temp is like at the end of the shower hose. If it is the same flow/temp as what comes out of the bath mixer - The the shower head is your problem..

Another thought.. I'm guess you have to select which way the water goes using the bath mixer.. Either "down" to the bath or "up" to the shower.. Maybe it is the diverter valve in the mixer unit that is faulty - clogged or only opening partially. 

Great yes the water mixes perfect at the height of the shower head (with the shower head removed) but its very very strong pressure. yes your description of how the water goes is correct

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2 hours ago, InMyShadow said:

The shower head is 6 months old so no grit in that . Whats a back flush?

 

If there is no grit then it must be limescale as I mentioned earlier (and which is much more likely). Only those two things can affect the shower head as far as I know.

 

Treat limescale with long hot vinegar soak as I described.

 

A back flush just involves pumping water backwards through the shower head which should flush out any impurities (but not limescale which is a deposit).

23 minutes ago, InMyShadow said:

Great yes the water mixes perfect at the height of the shower head (with the shower head removed) but its very very strong pressure. yes your description of how the water goes is correct

 

So there's your solution. Buy a shower head with a higher flow rate (more or bigger holes)

1 hour ago, KittenKong said:

 

If there is no grit then it must be limescale as I mentioned earlier (and which is much more likely). Only those two things can affect the shower head as far as I know.

 

Treat limescale with long hot vinegar soak as I described.

 

A back flush just involves pumping water backwards through the shower head which should flush out any impurities (but not limescale which is a deposit).

Thanks for all trouble shooting guys, appreicated