hot or cold

[dreadnought]

hi all,i`ve just about finished my nb fitout and took it out for a bit of a shake down trip over a week or so, i had a bit of an issue with the shower and hope you can help out,when the calorifier was full of hot water i had no way of controlling the temperature of the water it was either red hot or cold,i thought i had a problem with the mixer tap in the shower so i changed that to no avail, any advice much appreciated many thanks 

[jddevel]

Do you have separate taps to the galley and bathroom sink or are they of the mixer type? If so I assume the problem doesn`t exist there?

[dreadnought]

38 minutes ago, jddevel said:

Do you have separate taps to the galley and bathroom sink or are they of the mixer type? If so I assume the problem doesn`t exist there?

i only have mixer taps in the shower

[blackrose]

Calorifier water can get very hot indeed, but that doesn't really explain why you can't add cold water via your shower mixer.

In general, it may be worth fitting a thermostatic mixing valve to the outlet from the calorifier to prevent anyone scalding themselves on any hot water outlet. The only problem is that they tend to get blocked with bits of limescale from the calorifier (in hardwater areas), so you also need to fit a Y strainer before the valve.  

Edited August 1, 2017 by blackrose

[jddevel]

Unfortunately that doesn`t help then. Will think some more. I must admit mixer tap is the one I`d be looking at. I did have a  problem like this with the tubular type with on off/one end and thermostat the other. Never used them again. But that was no proof they did not work. Plenty are sold. Were isolating valves fitted in the pipe work to the shower mixer?

[mross]

Make sure that the hot and cold supplies to the shower have the same pipe run so that the pressure drops are almost equal.  

[frangar]

If it's a thermostatic shower bar then make sure the hot and cold are connected to the right inlets. They get upset if reversed....also make sure you have accumolator & expansion vessels fitted and pressured correctly.... when mine lose pressure it affects the flow and my shower mixer isn't as constant when the pump runs

[Tom766]

Hmmm I have a small cylinder, accumulator in the engine bay. Never heard of one before owning a narrowboat.

Just curious. Could someone please tell me in laymans terms why I need one and is it for the hot or cold water?

 

Tom.........learning quickly here :-)

[ditchcrawler]

Are the hot and cold pipes connected up the right way round on the back of the shower. if the hot is feeding the cold the thermostatic valve will ask for more hot water instead of cold.

 

 

Just seen Frangar said the same thing before me.

Edited August 11, 2017 by ditchcrawler
Some one else said it

[MtB]

On 8/1/2017 at 18:09, dreadnought said:

i only have mixer taps in the shower

 

Blood out of a stone.

What sort of mixer tap, exactly? Make, model and photo please!

[frangar]

9 hours ago, Tom766 said:

Hmmm I have a small cylinder, accumulator in the engine bay. Never heard of one before owning a narrowboat.

Just curious. Could someone please tell me in laymans terms why I need one and is it for the hot or cold water?

 

Tom.........learning quickly here :-)

Have a search on here for Accumulator & Expansion vessel.

Basically the accumulator goes after the cold water pump and is set to just below the pump cut in pressure and the EV goes either on the cold feed to the calorifier AFTER the non return valve or  on the hot outlet and is set to just above the pump cut out pressure. Physically the units are identical. 

[WotEver]

5 minutes ago, frangar said:

Have a search on here for Accumulator & Expansion vessel.

Basically the accumulator goes after the cold water pump and is set to just below the pump cut in pressure and the EV goes either on the cold feed to the calorifier AFTER the non return valve or  on the hot outlet and is set to just above the pump cut out pressure. Physically the units are identical. 

And the purpose of an accumulator is to reduce the amount of pump cycling whilst the purpose of an EV is to accommodate the expansion of the water as it heats. 

[frangar]

Just now, WotEver said:

And the purpose of an accumulator is to reduce the amount of pump cycling whilst the purpose of an EV is to accommodate the expansion of the water as it heats. 

That as well! 

[MtB]

1 minute ago, frangar said:

That as well! 

 

Surely it's one or the other. Neither is 'as well'.

Although on a calorifier with no NRV on the inlet, one EV will perform both functions. 

[frangar]

Just now, Mike the Boilerman said:

 

Surely it's one or the other. Neither is 'as well'.

Although on a calorifier with no NRV on the inlet, one EV will perform both functions. 

It's far too early and I haven't had enough tea yet to get arsey about semantics. 

Depending on the size of calorifier if you fitted just one EV it would need to be much larger than what is readily available if you were to comply with the requirements set out by the calorifier manufacturer thus making any warranty claims void. Also without an NRV especially on a horizontal calorifier you do seem to get some backflow of hot water into the cold feed. 

[dor]

Do you have separate hot and cold water pumps?  I did this when I fitted out the boat, but because they were always varying in pressure depending on how full the accumulators

 were; and even with a thermostatic mixer the temperature varied because it couldn't react fast enough.  I now run it with one pump and the hot and cold linked with no problems.

[pearley]

When built we had a bar type thetmostatic shower valve. Worked perfectly ok but with wet, old hands it was difficult to gripl the controls. So we bought a new, single lever one from Bathstore after telling them the pump pressure. When I fitted it it would only give hot water, treading the instructions it said to remove the cartridge andcrrpkacebit the other way round. Then it would only give cold water. Bathstore sent me a new cartridge but had the same results.  Sent the whole mixer valve back to the manufacters who could find no fault so Bathstore replaced it with a bar type, like the original but with levers we could grip. Works perfectly.