Fitting a mixer tap

[NealP]

I have recently fitted a mixer tap to my boat the cold system works really well but the hot water dose not flow at all on the new tap the heads tap still works, I checked for a blockage and all is clear. the old tap had a hot and cold valve so I was wondering if it may be a flow issue.

Some ideas how to get this working would be great.

Thanks

 

[Oldhairy]

It sounds as if it might just be a pressure difference problem. If the taps are of the domestic " floating valve" type the higher pressure side can back pressure the other valve to close.
Is it possible to choke the cold water supply?

 

[NealP]

I suppose I could fit a valve to restrict cold the flow. do you think that may work?

 

[SHUG]

If the cold water side is turned off, the hot water side should operate independently????

 

[pvb]

It sounds as if it might just be a pressure difference problem. If the taps are of the domestic " floating valve" type the higher pressure side can back pressure the other valve to close.
Is it possible to choke the cold water supply?

Why would there be a pressure difference? Boats usually only have one pressure pump.

 

[Oldhairy]

Why would there be a pressure difference? Boats usually only have one pressure pump.

Restricted flow through the heater.

 

[Oldhairy]

If the cold water side is turned off, the hot water side should operate independently????

Oops missed that in my previous post. Yes, it should.

 

[pvb]

Restricted flow through the heater.

I don't think so!

 

[pvb]

I have recently fitted a mixer tap to my boat the cold system works really well but the hot water dose not flow at all on the new tap the heads tap still works, I checked for a blockage and all is clear. the old tap had a hot and cold valve so I was wondering if it may be a flow issue.

Some ideas how to get this working would be great.

You could start by swapping the hot & cold pipe connections - that will show you whether there's a fault in the tap itself.

It's highly unlikely to be a pressure difference problem - both hot and cold water are pressurised to the same level by the pressure pump. However, some mixer taps do quote a "minimum pressure", so you might check if yours needs a minimum pressure to work properly.

 

[ostell]

When I've fitted domestic mixer taps (boat is probably the same but more expensive) the water paths are kept separate until the leave the end of the tap. I did have one tap where the cold wasn't flowing properly (only small flow) and it was a blockage in that side of the tap. Hot flow was fine.

 

[NealP]

I shall try to swap over the pipesto check the tap, I think the tap is ok so it may be my old water pump is not strong enough for this tap to keep the pressure up so when I open up the hot water there is no pressure drop to start the pump. Do you think that could be part of the problem?

 

[pvb]

I shall try to swap over the pipesto check the tap, I think the tap is ok so it may be my old water pump is not strong enough for this tap to keep the pressure up so when I open up the hot water there is no pressure drop to start the pump. Do you think that could be part of the problem?

Sounds unlikely, the water in the pipe connected to the tap will be at the normal pressure (dictated by the pressure switch on the pump). Unless the tap's faulty, opening it must allow water out, which reduces the pressure and triggers the pump to start. If you have an expansion tank, there'll be a delay before the pump starts.