Problem with water temperature

[blocko]

Hi all,

I completed a full bathroom installation at the start of the year and the homeowner has just contacted me stating the following problem....

...... over the past two months the client has lost all hot water from the shower. He said that this happened slowly, and seemed to be getting colder with each shower they had. It is now running cold, no matter what temp the shower is turned to. He has replaced the shower mixer with no success.

• He has a Triton thermostatic mixer shower fitted (with a salamander pump).
• The cold is mains and hot from a vented hot water system.
• The hot runs hot from the basin tap in the same room
• Hot water elsewhere in the house is fine
• Pump is working fine with no problems
• When cold is isolated, the hot works fine again
• His overflow from the loft tank has been dripping a fair bit since builder did pipework

I have a feeling that the pressure is to blame, and a PRV on the cold 15mm supply into the shower room would resolve...... or am I barking up the wrong tree??? Any help is appreciated as I would really like to sort this for them.

 

[SimonG]

Why is cold on the mains and hot vented? Is it twin impeller salamander? What model of Triton?

 

[Ian10261]

I'd check to see if theres any filters on the valve inlets, the hot could be blocked there, also some valves have check valves inside which can also cause problems. If its a twin impeller pump with cold supplied from the mains then thats dead wrong, hot AND cold should always be supplied via a tank as showers require equal pressures to work correctly.

 

[justlead1]

Hi As has been suggested. Take a cold feed from the cistern and pump that rather than from the mains. Which is a no,no any how.

 

[AWheating]

most thermostatic blending/mixing valves will not work correctly if the pressure between the hot and cold has 1bar or more difference, so this may be a problem. If the problem has only occured since a builder has altered the tank in the loft then i would also consider debris in pipework.

 

[Plumbstar Tom]

why is the hot taken from te basin tap?

Showers need a dedicated supply

 

[Resolute]

why is the hot taken from te basin tap?

Showers need a dedicated supply

I think he meant that the hot tap at the basin runs fine. The shower has a dedicated feed via a pump - at least that's how I read it!

Although I don't have much experience I'd look at filters on pump and shower first. Is it a hard water area?

 

[Paulus]

Mains cold water to shower via a pump is a definite no-no due to pressure difference. I'm 90% certain that is the problem. Take a cold feed from cistern instead.

 

[Plumbstar Tom]

I think he meant that the hot tap at the basin runs fine. The shower has a dedicated feed via a pump - at least that's how I read it!

Although I don't have much experience I'd look at filters on pump and shower first. Is it a hard water area?

I hope your right
Yep filters on shower and pump but I agree that the pressures probably causing this issue
Should always be balanced supplies
so both should be pump in this case

 

[blocko]

I think he meant that the hot tap at the basin runs fine. The shower has a dedicated feed via a pump - at least that's how I read it!

Although I don't have much experience I'd look at filters on pump and shower first. Is it a hard water area?

Shower has a dedicated supply, and it is a hard water area.




Is fitting a Pressure reducing valve (to match that from hot supply) a viable option as all pipes now in stud walls and tiled!

 

[blocko]

Also.... No debris in pipes, rest of cold and hot supply in house is fine (but is on gravity fed cold!), the pump is a twin impeller salamander (CT50 1.5bar), the shower is a Swirl Thermostatic mixer (sorry, thought it was Triton!)

I could always just swap cold supply in loft from mains to gravity, but was wondering if a PRV is the better option???

I just cant understand why it worked for sometime, then went cold. If I turn cold supply off at isolation valve, the hot works straight away?!?!?!

 

[Ian10261]

As mentioned before, you only need to take a feed from the CWSC down to the pump, do away with the mains supply to it, and bingo, equal pressures, job sorted.

 

[gmac]

As as been said the issue seems to be your mains supply to the pump (which is not allowed, stated previously also) so as you said swap mains over to gravity and you should have a perfectly working shower.

When you have isolation valve open mains pressure is most probably greater than the 1.5bar generated by the pump and overpowering the hot supply.

Also look up installation instructions online if you do not have a hard copy, will tell you all you need to know.

 

[blocko]

If, and only if he is adamant that he wants to keep the pipework the same, would a PRV be a viable option please???

 

[gmac]

No, regulations don't allow it and it also invalidates manufactures warranty

 

[blocko]

That answers that then! ...... pipe swapping here I come!

 

[gmac]

Here's a link for installation instructions.

[DLMURL]http://www.designer-bathroom-taps.co.uk/Salamander%20Installation%20Guides/salamander-installation-guide.pdf[/DLMURL]

 

[gmac]

That answers that then! ...... pipe swapping here I come!

Think of the ££££££££££

 

[blocko]

Yep, but the loft space is horribly tight!!!! I hate lofts !!!!