Shower issue now Hot water issue!

[Scott_1979]

Went to a house today to look at a shower running like warm. All other outlets run hot water fine. Took the shower mixer to bits and seems to be the thermostatic cartridge is gone. Drained the hot and cold as normal and on repressuring some of the other outlets are now Luke warm.

Kitchen tap; running red hot, bathroom upstairs tap; red hot. upstairs Bath (previously hot) now cold, ensuite bar mixer (previously hot) now cold. And the shower I went to see still Luke warm. Any ideas?

All I touched was the stop tap, the only thing I thought of is really high cold water pressure overwhelming the hot, bath and showers are all mixers. The stop tap has been dialled right down and the flow on the outlets running slow enough to kick the boiler in and still cold.

It's a pressurised system with a Worcester Bosch combination boiler. Working fine then one drain down and it's all gone Pete tong!!

 

[Amateur]

As an Amatuer guess id say one of the shower mixer valves is kaput and is letting the cold water into the hot pipes. Quick Google on it brings up same problem for other homeowners.

Im interested to see what it actually is though as I have a mixer shower myself. Hopefully one of your fellow pro's will have had this happen before.

 

[Ant Parkes]

When you say drain down you mean cold mains off & open hot and cold taps downstairs?

Did you change the cartridge or just put back together?

 

[Scott_1979]

Just got back from the gents now. Took his bath panel off and installed an iso. Turns out his cold water pressure had been overwhelming the hot in the bath and two showers. So all sorted now, just weird how it all worked before I drained the hot and cold. Not sure what I triggered but seems to have resolved the issue.

 

[Amateur]

Glad you got it sorted. Sorry for my lack of knowledge, just interested to know incase this issue ever happens to me.

Did you fit an iso to balance the cold water pressure or for another reason?

I mentioned the shower as that was my first thought and then when i Googled it loads of people had the same problem you described. Some replaced the shower to sort it and others fitted check valves to stop the cold getting into the hot.

Cheers

 

[Scott_1979]

Glad you got it sorted. Sorry for my lack of knowledge, just interested to know incase this issue ever happens to me.

Did you fit an iso to balance the cold water pressure or for another reason?

I mentioned the shower as that was my first thought and then when i Googled it loads of people had the same problem you described. Some replaced the shower to sort it and others fitted check valves to stop the cold getting into the hot.

Cheers

Yeah the ISO was installed to tone down the cold water pressure which was affecting the hot to the bath tap and showers.

 

[ShaunCorbs]

FYI if you use an ISO to control the pressure your wrong It will only slow the flow you will actually get more pressure

 

[Amateur]

FYI if you use an ISO to control the pressure your wrong It will only slow the flow you will actually get more pressure

Would you have fitted an in line PRV instead then Shaun even though it has done the job?

As mentioned in another thread I partially closed an isolator on my bathroom sink to reduce the flow as the mixer tap loved to fire the water out of the sink if you fully opened it. One of your fellow professionals informed me that although it solved the problem it would probably lead to a knackered/leaking isolator further down the line.

Im not sure how being partiality turned would cause it to seize and leak though any more than it being fully open and not turned for years like most isolators are. I have had them weep myself when fully open and you try to close it, always annoying!

 

[ShaunCorbs]

Yes it would scale and seize up due to the water hitting it square on and you might not be able to close it due to the scale

 

[king of pipes]

a pressure reducing valve would have been a better option to balance out the pressures . kop

 

[Amateur]

Yes it would scale and seize up due to the water hitting it square on and you might not be able to close it due to the scale

Ah I see, something new learned today! Thanks for the explanation Shaun.

 

[townfanjon]

Would you have fitted an in line PRV instead then Shaun even though it has done the job?

As mentioned in another thread I partially closed an isolator on my bathroom sink to reduce the flow as the mixer tap loved to fire the water out of the sink if you fully opened it. One of your fellow professionals informed me that although it solved the problem it would probably lead to a knackered/leaking isolator further down the line.

Im not sure how being partiality turned would cause it to seize and leak though any more than it being fully open and not turned for years like most isolators are. I have had them weep myself when fully open and you try to close it, always annoying!

These are what you need palhttps://www.savemoneycutcarbon.com/product/wondervalve-inline-flow-restrictor/

 

[Stigster]

Ah I see, something new learned today! Thanks for the explanation Shaun.

People including long time plumbers are often confused about flow rate and pressure and the relationship between the two. You can have very high flow rates with low pressure e.g. a very big outlet with a big feed could be low pressure/high flowrate.

Or you could have a tiny outlet with a small feed but crank the pressure right up to match the flow rates of the scenario above but it'd take your skin off if you showered under it.

People are frequently talking about reducing pressure when they mean flow rate and vice versa.