Shower Runs Hot and Cold....

[Trem]

Hi all, I have searched this issue but it seems unique.

I have an Aurlane shower fed by the combi, combi has had a complete overhaul and this problem was around before and after the combi work. The boiler fires up fine and stays constant when the shower is used.

I have changed the cartridge, shower head and hose.

The problem - the shower on the usual hose/head fitting runs hot then cold but if we use the overhead (rainfall?) shower thing it's fine, works as it should with no hot/cold issues, the overhead shower is rubbish though. You can't clean yourself properly. This is driving me mad and no amount of searching has helped and it seems a Google search reveals no one else has this issue.

Please help!

 

[Johntheo5]

Can you compare (measure) the flow from each by holding a bucket/container under each for exactly 1 minute (or 30 secs) , then measure this with a 1 litre container to give you the flowrate in LPM.

Is the DHW combi temperature set to 60C?.

 

[Trem]

Can you compare (measure) the flow from each by holding a bucket/container under each for exactly 1 minute (or 30 secs) , then measure this with a 1 litre container to give you the flowrate in LPM.

Is the DHW combi temperature set to 60C?.

Hi, thanks for your reply.

Did the measure and the rainfall shower was roughly twice as much as the hose/head/problem shower. But could this be because the rainfall shower fitting is at least twice the size?

Combi was set by the Baxi engineer who maintained it, it's over half way on the temp dial but not at the maximum (it doesn't have temperature in numbers just a whoosh symbol).

 

[Johntheo5]

It would be useful to know the actual flowrate from the problem shower head. Also the combi model and the max and more importantly the minimum output. Assuming a minimum output of say 6kw and the combi DHW temp of 40C then the min flowrate from the shower will only have to be ~ 4.3PM to maintain this temperature so shouldn't be a problem, if the combi DHW temp is 60C and if the minimum flowswitch setting is 2.5LPM (fairly typical) then the shower flowrate must be > 5.0LPM to give a showering temp of 40C, again shouldn't be a problem, its possibly but unlikely that the cartridge is faulty and stuck in one position, can you turn the DHW temperature control to max and see if the problem still persists.

If you find that the flowrate is ~ 6LPM then check for a restrictor somewhere, maybe in the shower head??.

 

[Trem]

It would be useful to know the actual flowrate from the problem shower head. Also the combi model and the max and more importantly the minimum output. Assuming a minimum output of say 6kw and the combi DHW temp of 40C then the min flowrate from the shower will only have to be ~ 4.3PM to maintain this temperature so shouldn't be a problem, if the combi DHW temp is 60C and if the minimum flowswitch setting is 2.5LPM (fairly typical) then the shower flowrate must be > 5.0LPM to give a showering temp of 40C, again shouldn't be a problem, its possibly but unlikely that the cartridge is faulty and stuck in one position, can you turn the DHW temperature control to max and see if the problem still persists.

If you find that the flowrate is ~ 6LPM then check for a restrictor somewhere, maybe in the shower head??.

I'll go do the max temperature on the combi shortly and I really appreciate that incredibly detailed reply. I'll also try and get the combi details (it's in the loft so a little annoying sometimes).

One thing I forgot to mention, there's a definite audible change from the shower when the temperature drops, it makes a sort of mild whine as it's spraying you with cold water.

Thanks again.

 

[Johntheo5]

Don't forget to measure the flowrate as well.

 

[CBW]

Check for mixer valve crossover, isolate the cold feed under the boiler and run the shower from head/hose on hot, if water comes out, likely to be the problem.

 

[Trem]

Check for mixer valve crossover, isolate the cold feed under the boiler and run he shower from head/hose on hot, if water comes out, likely to be the problem.

I have limited knowledge of what I'm looking for there, BUT a new development has occurred -

Combi is a Baxi Combi HE30, all major parts replaced last year by Baxi. Anyway it's bloody lucky I was doing the hot water temp test because on entering the loft I saw we had a mother of all leaks coming from underneath the boiler, I had an empty storage tub under the boiler which was almost full! So if nothing else cheers lads.

Also, the flame does come on with the problem hose/head but then it does go off, this is new. As before it stays on constant with the rainfall shower.

I'm at a loss.

 

[CBW]

I have limited knowledge of what I'm looking for there, BUT a new development has occurred -

The cold feed which enters the boiler, in turn gets heated and comes out of another pipe to give you this heated water (hot water). The cold feed will have an isolation valve and the hot usually doesn’t, and it should be 15mm, so thinner of the several pipes underneath

a mother of all leaks coming from underneath the boiler, I had an empty storage tub under the boiler which was almost full! So if nothing else cheers lads.

Fix the leak, or get it fixed if you’re unable yourself.

 

[Johntheo5]

If doing the Xover test, the cold water inlet is probably item 13.

 

[Trem]

If doing the Xover test, the cold water inlet is probably item 13.

View attachment 306678

 

[Trem]

I messed up the multi quote.

I have hopefully fixed the leak. It was like a sauna up the loft, horrible.

Many, massive thanks lads, I will try your suggestions tomorrow when it's a little cooler up there.

Will report back.

 

[Trem]

I turned off the water to the boiler (I'll attach a pic, I turned the off where the silver flexi-hose is) and the shower continued to run.

 

[CBW]

I turned off the water to the boiler (I'll attach a pic, I turned the off where the silver flexi-hose is) and the shower continued to run.

It’s the one above the braided hose on the boiler. If you turned that off and the shower ran (opening hot side only) then I’d say you’ve found your culprit

 

[Trem]

It’s the one above the braided hose on the boiler. I feel you turned that off and the shower ran (opening hot side only) then I’d say you’ve found your culprit

I turned both off (one then the other) but the one on the boiler was super stiff to the point where I thought I was going to break the plastic handle thing on it.

The culprit being the diverter valve? How is the rainfall shower still working good?

I reckon we need a new boiler at this point.