Venturi Shower Trevi Boost

[johnny avocado]

Posted 6 weeks ago regarding mains cold and low pressure hot feed for shower. Bought a Trevi Boost venturi shower and it looks good. Just installed it however and I am having problems getting any kind of temperature from the shower.

I understood that it would work with up to 3 bar mains pressure, mine is around 2.5 bar. I have increased the temperature of hot water to around 60 and slightly above.

The only time you get any heat through the system is when you throttle back the mains stop cock to a flow rate similar to the hot. In this case it only provides a dribble and is effectively working as a non thermostat mixer.

Am I missing something here? By throttling back the cold I am adjusting the inlet cold pressure which will affect the performance graphs.

I though I could leave the stopcock for the cold feed open and adjust the flow on the valve to get the right temperature.

Any views or any help, I dont want to scrap all the work done so far.

Also, fitted a shallow trap to the shower tray, slight leaks, should I use silicon sealant?

Thanks

JA

 

[EliteHeat]

That doesn't sound right at all. I have just installed a Trevi Boost (external) and find it to be really good.

I couldn't even meet the specs and install a 22mm hot supply, so mine is running off 15mm.

The way mine works is that the higher the cold flow the hotter it gets, mind you, it is dependant on the hot water temperature to a high degree - mine is about 65 degrees.

I think that maybe you should be talking to Trevi.

 

[Softus]

Have you followed the MIs to the letter? Did you fit NRVs? Did you fit them the right way around?

If "yes" to all of that, then I agree with EliteHeat - that valve sounds faulty to me.

 

[johnny avocado]

I have installed check NRV's and the arrows point in the right direction.

I have a gate valve on the hot and a stopcock on the cold.

When the cold is fully open the water hammers out of the shower head, but freezing. When I turn the cold valve of the hot water comes out of the shower head at a fairly low rate but nothing you wouldnt imagine based on a head of about 1m. However, whilst the cold is shut off, the hot stops running after about 30secs, perhaps due to the thermal cut off valve, but the water doesnt seem overly hot when this happens.

When the hot is running, if I turn on the cold stopcock the flow increases, the temperature remains just about ok until the cold flow gets in excess of the hot, then the temperature dramatically falls.

Trying to judge it, it seems to be working as no more than a standard mixer valve, as soon as you get a flow rate in the cold in excess of the hot the temperature is bloody cold! In all cases the temperature valve is at the top temperature.

Would I be correct in assuming that the system should work with the cold stopcock fully open? Or would it be normal to throttle it back inthis type of installation.

Both supplies are 22mm as are the NRV's

Cheers

JA

 

[EliteHeat]

You could always try removing the gate valve, and even temporarily removing the NRV to see if is excessively 'sticky'.

 

[Balenza]

johnny avocado wrote

Both supplies are 22mm as are the NRV's

Are they spring loaded NRV,s. ???
If they are , then you have installed a major flow restriction for 1 m head of gravity pressure to overcome.
I dont see the need for one in the hot supply.
Do the MIs stipulate one ?.
If so then a swing check valve should be used which is designed for low pressure systems.

 

[Softus]

I dont see the need for one in the hot supply.

Then you've never read the Trevi Boost MIs.

Do the MIs stipulate one ?

Do you actually know the first thing about the product you're attempting to advise about?

 

[Balenza]

I dont see the need for one in the hot supply.

Then you've never read the Trevi Boost MIs.

Do the MIs stipulate one ?

Do you actually know the first thing about the product you're attempting to advise about?

Thats why I asked did the MI,s stipulate one or cant you read.
Obviously from your reply they do though I would be surprised if they advise fitting anything other than NRV,s designed for low pressure systems .

Why dont you fill me in and while your at it why dont you try pulling your head back out from your backside.
Or is it so far up there that its stuck.??

 

[Softus]

Go away BigBurn - the Tellytubbies are no doubt awaiting your advice.

 

[Balenza]

Go away BigBurn - the Tellytubbies are no doubt awaiting your advice.

Nah,think I shall stick around for a while. This one should be interesting.
Anyway Im hoping to see you proved wrong about the valve being a duff one.

 

[Softus]

//www.diynot.com/forums/viewtopic.php?p=613057#613057

 

[Balenza]

//www.diynot.com/forums/viewtopic.php?p=613057#613057

Meaning

 

[Softus]

 

[Balenza]

Whats that ? Your head ??
Now I see why you can't extract it from your rear end.

 

[Softus]

I stand humbly corrected - it turns out that you're more stupid than I thought possible.