Thermostatic Shower too hot in summer to cold in winter

[ado]

Hi,

Hopefully some one can help or point me in the right direction to get help on this. We got a new Combi boiler (Glowworm 30CXi) and thermostatic Shower (Quatra by Crosswater I think from the bathstore) last October. At the time the shower seemed fine and hot, however we never used it much until the bathroom was tiled over. When we started using it regularly in November, I found it ok not very hot where as the wife, who likes a hot shower found it cold. All the other hot taps in bath and kitchen produced scaling hot water. Eventually as the winter wore on, I too found it too cold and the only way to have a hot shower was to turn on the cold water tap on the bath. This was inconvenient, but we had 101 other things going on in our lives to try and fix it back then, so we lived with this inconvenience. Now however in summer the opposite has happened and the shower is scaling, turning the exposed temperature valve/knob to min and turning the water temperature on the combi to minimum (without turning it off) makes no difference. Even turning on the hot tap in the bathroom makes no difference, the pressure drops but the temperature is still too hot. We=92ve ended up going to the gym to have cooler showers. I rang the plumber and he blamed first the boiler, =93should have went with worcester bosch=94 and then blaming the thermostatic value. So I want to educate my self on possible causes so I can confront him to fix it (if it is indeed an installation error).

Cheers Adrian

[ado]

Hi,

Hopefully some one can help or point me in the right direction to get help on this. We got a new Combi boiler (Glowworm 30CXi) and thermostatic Shower (Quatra by Crosswater I think from the bathstore) last October. At the time the shower seemed fine and hot, however we never used it much until the bathroom was tiled over. When we started using it regularly in November, I found it ok not very hot where as the wife, who likes a hot shower found it cold. All the other hot taps in bath and kitchen produced scaling hot water. Eventually as the winter wore on, I too found it too cold and the only way to have a hot shower was to turn on the cold water tap on the bath. This was inconvenient, but we had 101 other things going on in our lives to try and fix it back then, so we lived with this inconvenience. Now however in summer the opposite has happened and the shower is scaling, turning the exposed temperature valve/knob to min and turning the water temperature on the combi to minimum (without turning it off) makes no difference. Even turning on the hot tap in the bathroom makes no difference, the pressure drops but the temperature is still too hot. We=92ve ended up going to the gym to have cooler showers. I rang the plumber and he blamed first the boiler, =93should have went with worcester bosch=94 and then blaming the thermostatic value. So I want to educate my self on possible causes so I can confront him to fix it (if it is indeed an installation error).

Cheers Adrian

[John]

"ado" wrote in message news: [e-mail]... Hi,

Hopefully some one can help or point me in the right direction to get help on this. We got a new Combi boiler (Glowworm 30CXi) and thermostatic Shower (Quatra by Crosswater I think from the bathstore) last October. At the time the shower seemed fine and hot, however we never used it much until the bathroom was tiled over. When we started using it regularly in November, I found it ok not very hot where as the wife, who likes a hot shower found it cold. All the other hot taps in bath and kitchen produced scaling hot water. Eventually as the winter wore on, I too found it too cold and the only way to have a hot shower was to turn on the cold water tap on the bath. This was inconvenient, but we had 101 other things going on in our lives to try and fix it back then, so we lived with this inconvenience. Now however in summer the opposite has happened and the shower is scaling, turning the exposed temperature valve/knob to min and turning the water temperature on the combi to minimum (without turning it off) makes no difference. Even turning on the hot tap in the bathroom makes no difference, the pressure drops but the temperature is still too hot. We?ve ended up going to the gym to have cooler showers. I rang the plumber and he blamed first the boiler, ?should have went with worcester bosch? and then blaming the thermostatic value. So I want to educate my self on possible causes so I can confront him to fix it (if it is indeed an installation error).

Cheers Adrian

I had a problem of mine not being hot enough in the winter. This was due to the water entering my combi being very cold - and the shower having a high flow rate (13 litres minute). The combi was struggling to keep pace. I fixed it by fitting a flow restrictor (from Mira) in the hose outlet. This reduces the flow to a more manageable 9 litres a minute which is more within the capabilities of the boiler ( and it no longer knock my grandson over). However, this won't help your summer problem. - Unless you have some shut off valves somewhere and the cold water has been throttled back a bit to help the winter problem

[Roger Mills]

It sounds as if the "thermostatic" valve is nothing of the kind, but is simply giving you the same hot/cold mixture regardless of how it is set, and regardless of the mixed water temperature.

If this is the case, the mixed temperature will depend only on the temperature of the incoming cold mains - and so will be hotter in summer than in winter.

[meow2222]

Problems like that tend to respond to turning the water flow down at the shower. If it makes no difference, I can only see it being the 'static shower thats the probelm. I'm no plumbing expert tho, prefer to avoid it.

NT

[ado]

Hi Guys,

Thanks for the responses,

Cold Water in winter: I didnt think the shower was overly powerful but there is a good flow rate. So a flow restricter would reduce the speed at which the water flows through the boiler and allow the boiler to heat up the water better. Is this what is currently happening when I turned on the cold water bath tap in winter a little, which reduces the pressure on the shower a bit but caused the shower to go hotter? Unfortunately our pipes are all tiled over and the shower head is a fixed one, so can the flow restricter sit between the shower head arm and the pipes? Also how would this differ from turning down the power of the shower using the flow control know on the shower? I guess I can't test this out now until winter as at the moment the water is just mad hot.

Hot Water in Summer (or more importantly no cold water): I am assured it is a thermostatic shower value. There are only two knobs on it, a temp control and a flow control. Its not possible to control the mix manually, but yea its not behaving as a thermostatic valve as there is little or no difference when the temp control is set to hot and when its set to cold.

There is a restriction Value on the Bath taps set to reduced but not the shower (I think). Basically the mains water comes into our flat before splitting in two and 1 goes to the flat upstairs as their mains and the other is ours. Because it comes into our flat first upstairs asked us to restrict the flow on the bath as when the previous owners turned on the bath fully their shower was rendered useless as we took all the water. So we agreed as it just meant the bath filled a little slower and we didnt use the bath much. So is this the source of our lack of cold water going to the shower?

Cheers Adrian

[sm_jamieson]

Could themo valve be connected back to front (hot to hot, cold to cold) ? So if the temp is too low, it makes it lower, if too high it makes it higher. Not sure if they would react like this though. Also, there is usually a high temp cutoff, but this may not work if the connections are reversed. Simon.

[sm_jamieson]

Of course I meant hot to cold, cold to hot. Simon.

[Ed Sirett]

I agree. First thing is to see if you can mix water at a reasonable flow and temperature from manual tap(s) on the basin/bath/sink.

If so, then the focus is on the duff mixer. It is amazing how many units a the lower end of the market are borken/nearly broken/out of calibration. The lower end kit invariably uses wax pellet expansion technology which can and does go wrong.

[ado]

Hide quoted text -

Hi,

Okay I shall take the front plate off tonight and see if its all connected up correctly, I'd be surprised if the plumber did connect it the wrong way around, however it needs to be eliminated as a cause. I can get a reasonable flow/mix from the bath and sink mixers. As a matter of interest, is the theromostaric valve we bought for =A3250 at the lower end of the market?

Cheers A

[Mathew Newton]

Out if interest what does the upper end kit use (and a brief explanation of operation if it's not obvious)? Presumably the Mira Excel falls into this category?

Mathew

[Rick... (The other Rick)]

Hi, I can't comment about a combi system, but I have experienced the same from a conventional hot water system with a pumped shower.

My conclusion was that the temperature differential of the hot and cold water was to blame. When leaving the tank stat alone I would get the same symptoms as you. Therefore I experimented, and discovered the following... In winter, when the water in the loft tank was cold, I turned the hot water tank temperature down, this not only increased the temperature of the shower, it increased the flow rate as well.

In summer I could increase the hot water tank temperature and experience even better flow rates.

When we had a wood burning stove with a back boiler fitted, we had it plumbed into the C/H system as well. So now the hot water could rise to 80C+ Something had to be done...

To prevent these temperature / flow fluctuations, I had a thermostatic pre mixer fitted to the hot input of the shower pump set at approx 50/60C. This appears to have solved the problem.

I now get constant flow rates and temperatures throughput the year.

I think that your problem is due to the high water temperature from your boiler and the fluctuating temperature of the incoming cold water supply. Try turning the hot water temperature down and see what happens.

Rick... (The other Rick)

[sm_jamieson]

high end uses some kind of bimetallic coil that responds faster than wax pellets. The coils are very expensive to replace. In this day and age, and for my next installation, I may try an electronic mixer. The mixer is remote (e.g. in loft) so no probs with wiring. I mean, come on, bimetal, wax pellets - how crude is that ! Of course it does work without power which is of no benefit if you have a combi that needs power to function. Simon.

[Pete C]

Hi,

Try phoning the shower manufacturer, if it costs =A3250 there must be a well staffed technical helpline.

cheers, Pete.

[John]

werwas to turn on the cold water tap on the bath. This was

Hi,

This sounds like the boiler is the problem. Might be worth getting the manufacturer out to have a look to confirm.

You could change your shower to a TMV2 which offer the ultimate thermostatic performance to TMV2 certified standards also prevents scalding by accurately maintaining a constant water temperature.

this helps.

John.