Is a PRV or Equalising Valve required?

[wimper]

I'm currently refitting my bathroom and am fitting a Triton Thames Thermostatic shower, on a combi boiler system.

Will I need to fit an valve, or will the mixer take care of it? I know the pressures are not even, but I'm wondering how much unevenness matters?

Should I commission the shower (before fitting the bath) to see if it deals with it, or would I be wasting my time?

Cheers,

Ian

 

[flameport]

I know the pressures are not even

How have you managed to get two different pressures with hot water from a combi?

 

[hansthebear]

put a couple of isolating valves on the hot and cold to the shower and use this to cut down the cold if required

 

[ChrisR]

If the cold is off the mains, you'll probably get away with it - check the shower specs. Very high pressure mains can be a problem.
COme back if that's the case.
If the cold's off a gravity fed tank, forget it - it won't work.

 

[wimper]

Cheers for the replies. While I was waiting, I fitted the shower and tried it out anyway. It works ok, better than a mixer tap, but the modulation between hot and cold could be better.

To answer a couple of questions...

I think the difference in pressures is because I am right on the water main, and I'm guessing the combi flow is limited by how quickly it can heat the water. But that's just me making an educated guess...

I have run with an isolating valve in the cold throttled back when I was using a mixer tap. It worked, but wasn't perfect. Now I am going to the effort of putting a nice bathroom in, I wanted something that worked right.

Yes the cold is off of the mains. I think the best answer maybe to put a pressure reducing valve on the mains inlet into the house. I could the throttle back to say 3bar, and have much better matched pressures.

Ian

 

[Dan Robinson]

You are confusing pressure and flow.

What boiler is it?

 

[wimper]

You are confusing pressure and flow.

What boiler is it?

Baxi Netatec 28

 

[Dan Robinson]

Just buy a flow limiting service valve for the cold. Cheaper and easier.