Thermostatic Shower not working

[DaveCha]

Hi folks,

I just had a thermostatic shower installed. The water is fed from a pump stored in the hot press (shower is high pressure while the house water system is low pressure).
The shower control is one of the horizontal bar types with the water flow control on the left and the temp. control on the right. The water is fed in from either end of the control bar.
We're finding that when we turn on the shower nothing happens until we turn on the sink tap (note: 2 taps & two showers, incl. this one, are on the pump). Turning on the sink tap kicks off the pump and allows the shower to work.
I've noticed that the hot water is fed in on the left side (water flow control end) whie the cold water is coming in on the right (temp. control end).
My own theory is that when the water flow is turned on the initial flow of water is from the left (hot) side. Given that there is insufficient initial pressure from the hot pipe, the pump won't start therefore no shower. I'm wondering if this theory is correct and if I get the plumber back in to reverse the pipes will that do the trick?

Any help appreciated.....

Thanks,

Dave

 

[breezer]

my theory is it wont make any difference what so ever. i agree with your "why it wont start" theory but the hot water is trying to go UP to the shower head so as it cant as you said lack of pressure, nothing happens.

to test my theory unhook the shower head and put it as low as it will reach then try it (oh and you will probably get wet)

Is there not "an adjustment" on the pressure switch

 

[DaveCha]

I removed the shower hose & head completely thought to no avail. This is the only thermostatic device on the pump...the other shower and two taps are normal hot/cold adjustments & work perfectly.....this is what makes me think that it is the flow from the left that is required before the thermostatic control on the right allows water from the right to mix. Do you not think that if the cold flow entered from the left, the additional pressure (water coming from attic) would be enough to trigger the pump?

Not sure where I would find the 'pressure switch'......water pump??

Thanks,

Dave