TMV query

[Robert Tyrrell]

Not having fitted a bathroom for a while, I started one the other day and I am having problems with the TMV so wondered if anyone out there might be able to offer some advice.
Th bathroom has mains pressure cold water and gravity fed hot. I have installed a Bulldog TMV with the mains rsing from 15 to 22mm and the hot as 22mm. The Bulldog TMV has a blue cap on it (I've seen some with a different colour cap so I'm making a point of it just in case) and I have installed it with the hot entering at the bottom of the 'T' that the Bulldog TMV makes, leaving from the 'H' port and connecting to the hot tap tail. The cold runs to the 'C' port and branches off to the cold tap tail.
The problem that I have is this:
There is a continual gurgling sound at the TMV and there is no hot water coming from the bath tap.
My questions are: (a) How does one pipe up the TMV - I did think that this would be obvious but I appear to have cocked it up somehow. (b) Is there a particular TMV for each solution such as when the pressures are unbalanced, they are big, they are low?
All sensible comments appreciated

 

[SimonG]

Why are you fitting a tmv if it's an existing bathroom swap?

 

[SimonG]

But your hots are the wrong way round. If the valve is a T, then the mix comes off the branch.

H-C
M

 

[Robert Tyrrell]

Why are you fitting a tmv if it's an existing bathroom swap?

For England and Wales, from 1 April 2010, revisions to Part G of the Building Regulations (Hot water supply and systems) include the requirement that baths, subject to building regulations, are fitted with a protective device (i.e. a thermostatic mixing valve) to limit the temperature of hot water. Similar regulations have been in force in Scotland since 2006.

Taken from here:
http://www.rwc.co.uk/products/thermostatic-mixing-valves-tmv

 

[gassafe]

Customers like a hot bath... Tmv won't allow this 🙁

 

[gassafe]

Best to go read installation instructions. Check its piped correctly and that the valve can accept mains & tank mix?

 

[Howsie]

For England and Wales, from 1 April 2010, revisions to Part G of the Building Regulations (Hot water supply and systems) include the requirement that baths, subject to building regulations, are fitted with a protective device (i.e. a thermostatic mixing valve) to limit the temperature of hot water. Similar regulations have been in force in Scotland since 2006.

Taken from here:
http://www.rwc.co.uk/products/thermostatic-mixing-valves-tmv

Can't see anything in their regarding existing installations.

 

[Destroyer2813]

I asked similar question while ago the consensus was if straight swap not needed but if its a new bathroom then yes

 

[AlexGas]

Here’s how to comply with the regs:
http://www.beama.org.uk/download.cfm/docid/2A88D3DB-182D-4F48-90D0FA013261BADA

 

[chris watkins]

It is likely to be the difference in pressure between the hot & the cold water, if you are still going to install it you will need a pressure reducing valve to equalize the cold to that of the hot. (because you are mixing hot & cold check valves will be install, hot is being held closed)

 

[SimonG]

For England and Wales, from 1 April 2010, revisions to Part G of the Building Regulations (Hot water supply and systems) include the requirement that baths, subject to building regulations, are fitted with a protective device (i.e. a thermostatic mixing valve) to limit the temperature of hot water. Similar regulations have been in force in Scotland since 2006.

Taken from here:
http://www.rwc.co.uk/products/thermostatic-mixing-valves-tmv

I know the regs, I also know if you are taking a bath out and fitting a new one in it's place then you don't need a tmv. The paragraph you have quoted says as much. 'baths, subject to building regulations', i.e. new build, conversion of a room into a bathroom etc etc.

If I was you I wouldn't be fitting it in this instance.

 

[Chalked]

Just something else to go wrong.
Fit them all the time on commercial, but never on domestic. Never been pulled up about it. So I'm going to wait until I do.

 

[SimonG]

Just something else to go wrong.
Fit them all the time on commercial, but never on domestic. Never been pulled up about it. So I'm going to wait until I do.

Only done a couple and the custs hate them

 

[Robert Tyrrell]

thanks very much for the advice and comments guys. I should have read the Building regs properly I suppose but I was led to believe that I needed to fit one as the bathroom was being changed from a 'Shower' room to a 'Bath' room. I'll rip it out in the morning. 🙂

 

[AWheating]

as chris stated its probably due to the differing pressure between the hot and cold. most tmv's wont work if the pressure difference is over 1bar, some as low as 0.5bar(check with the manufacturer) You can get a certain make that allows a bigger difference in pressures but they are 3-4 times the price of the average tmv valve.cant remember the name tho 🙁