Plumbing Question - Shower not hot

[Avo Mk8]

This?
View attachment 107974

Thanks
I don't want to hijack Mr moooore's contribution, but that seems to be a pump for hot and cold, maybe for the shower?
Is that a dented flexi or just my eyes?
Does it come on when you run the shower - should be able to tell from the noise/vibration!

 

[LukeD]

Its a temp controller for underfloor heating systems. But can still be used

Thanks again for talking me through - Again I do feel this might have happened since the new boiler but I could be way off.

Is this what you want?

View attachment 107969

and do you know what this is> it's in a cupboard near the shower room?

View attachment 107970

If you want higher def pictures let me know.

temp control unit designed for underfloor systems .But its fine

 

[Mark Wright]

Seems to.

 

[Mark Wright]

ill have a feel of those flexi pipes and see if they get hot?

I think that pump was fitted/replaced when the boiler was. So if the pump comes on with the shower and not the tap - the shower is fed from a different source?

 

[brianmoooore]

The feed for the shower hot does come from a special fitting that draws the water from slightly down the cylinder, and that is most definitely a shower pump on the end of the pipe that feeds from it.
Follow the flex from the pump to where it connects to a FCU, and see if it is switched on.
Also, check that the gate valve with the red wheel handle, near the top of the cylinder is fully turned on.

 

[Mark Wright]

The feed for the shower hot does come from a special fitting that draws the water from slightly down the cylinder, and that is most definitely a shower pump on the end of the pipe that feeds from it.
Follow the flex from the pump to where it connects to a FCU, and see if it is switched on.
Also, check that the gate valve with the red wheel handle, near the top of the cylinder is fully turned on.

Hi yes the pump comes on with the shower. I posted a video above but it's probably not showing

With the shower running the two flexi pipes at the front of the pump are warm but not hot

 

[Mark Wright]

The gate valve is open full - I closed it to see what would happen and it was still slightly warm? maybe cos the pipes were warm.

So I'm guessing something is not right with the feed to the pump. But cant understand why the tap is hot because it's from the same tank.

 

[brianmoooore]

Where does the flex from the pump go?

 

[Mark Wright]

The cable does go to an FCU and appears to be on.

 

[Mark Wright]

The cable to the immersion heater at the top is switched off?????

Ill leave it on an hour?

 

[Mark Wright]

I've rewired the cable to the immersion heater and ill do a continuity test on the element.

 

[brianmoooore]

The immersion heater would normally be switched off. It's only there to a) block up the big hole in the cylinder, and b) as an emergency backup if the boiler is out of order.
The problem with the shower is definitely the non working of the shower pump. Everything that has been discussed before is now irrelevant.
Do you have a non contact voltage detector (Volt Stick)? If so, wave it around the pump cable to see if it is live.

 

[mainline]

The immersion heater would normally be switched off. It's only there to a) block up the big hole in the cylinder, and b) as an emergency backup if the boiler is out of order.
The problem with the shower is definitely the non working of the shower pump. Everything that has been discussed before is now irrelevant.
Do you have a non contact voltage detector (Volt Stick)? If so, wave it around the pump cable to see if it is live.

The OP said that the pump comes on with the shower #66

 

[brianmoooore]

Ah, so that's what that short video was about. Doesn't come over very well on a laptop without sound. Listened to it on my phone now, and it doesn't sound very happy, but having been asked many times to diagnose car faults from videos, I know that's the norm.
The black connectors at the top of the pump flexible pipes often have quarter turn isolator valves built into them. If they are present, are they all fully on?
I've also come across pumps where there are little mesh filters built into the rubber washers between the nuts at the bottom of the flexible pipes and the pump.
All comments about the shower valve having a to high minimum pressure requirement are now invalid. Something's blocking the hot water flow.

 

[brianmoooore]

The connection at the top of the cylinder is known as a Sussex flange. Google it to see how it works.

 

[Mark Wright]

Thank you sir ill invvestigate.

 

[Mark Wright]

I'll just say with the with the immersion heater on it's too hot - on max its like boiling hot - its dangerously hot. I've switched it off for now.

 

[brianmoooore]

I'll just say with the with the immersion heater on it's too hot - on max its like boiling hot - its dangerously hot.

Is that from the shower head? With the temp. knob against the safety stop or overridden?

 

[mainline]

The connection at the top of the cylinder is known as a Sussex flange. Google it to see how it works.

Surrey and Warix flanges are top entry.
Essex flange is a side entry.

 

[Mark Wright]

Is that from the shower head? With the temp. knob against the safety stop or overridden?

Both - Remember I changed the calibration to be the total max. Now with the immersion on it's too hot -Dangerous.

 

[brianmoooore]

Essex flange is just a threaded boss with no internal 'works' . Can be used for a shower if fitted on the dome of the cylinder, but presents venting problems unless the pipework from it rises.

 

[brianmoooore]

Knob position needs to be sorted ASAP, then. That's why I said to mark the original position of the shaft.
Stored water temp. should be near enough the same whether heated by the immersion heater or the boiler. There's a thermostat under the cover of the immersion heater (electricity OFF), which may be marked in degrees, although they haven't been calibrated for many years. If it's an uncalibrated one it left the factory with the dial locked in place by a blob of sealant. Check for it having been 'got at', or it could just have gone wrong of course. if it has a calibrated dial, it should be set at 65 degrees.
The hot water temp, if the water is heated by the boiler, is set by the thermostat that can be seen strapped to the front of the cylinder. This should be set to 65 degrees as well. Can just make out the knob position in the pic, and it doesn't look far out.
The boiler flow temp. must be set slightly higher than the 'stat on the cylinder, otherwise the boiler will cycle on and off after the cylinder is 'full'. I suspect many boilers now suffer from this problem, following the misinformation put out by the government green brigade.

 

[Mark Wright]

So what are you thinking the Sussex flange is malfunctioning?

 

[brianmoooore]

Not much to go wrong with them, other than build up of scale.
First priority is to work out why there's a big difference in hot water temperature between that heated by the immersion and that heated by the boiler.
It would be interesting to disconnect the feed to the hot water side (at the front in the pic.) and see if you get a decent flow there.
Check than 'in' and 'out' are the right way around on the pump. Ignore that. I can see they are correct in one of the pics.

 

[Mark Wright]

Still so puzzled -
The tap gets hot
The shower doesn't
The hot water from the Shower goes through the pump
But both come from the same source
The flexible cables entering the pump aren't hot but warm
With the immersion heater on the shower gets hot.

But I think they did replace the pump and do some work on the S plan when the boiler was replaced - and I had a feeling this all happened when the boiler was replaced. I think they should come and fix it for her but they've already told here it was the shower and she had a new shower fitted on there advice.

 

[mainline]

I’ll refer to my post #4

It could be that with the higher water temperature, the Shower thermostat valve is opening.

When the valve isn't allowing a hot flow, your in and out of the pump is going to be cooler as there is little flowing though it.

 

[Mark Wright]

I mean I know nothing about this really but I can't understand why it's not entering the pump hot but the tap is ok. Anything I can try?

 

[Mark Wright]

I think ill leave it tonight. I've turned the thermostat at the front of the tank up to 65 it was at about 59.
I'll go back tomorrow and have a look - maybe one last go - and maybe I'll advise here to get them out to fix it.
But thanks again I really feel like this has helped and if they do come back I can mention the pump etc. I'm not looking forward to it I know there be all defensive etc.

 

[plugsandsparks]

Must admit, i am getting confused myself following this but do hope you get it sorted. At the moment i cannot fathom whether the pump runs both for hot water at the tap and shower.
1. Try run hot tap until water is hot, check temp at pump is it the same temp
2. Shut off hot tap and run shower until it is at its hottest, is the temp at the pump the same as the shower or same as when you ran the tap.

Reason i am confused is that there is talk of the shower take off from the cylinder being lower than the top take off and there is talk of the pump running when either tap or shower are running.

 

[Mark Wright]

I know, is confusing now 9 pages

But the pump is only used when the shower is on - So this has ruled out other things such as pressure issues.

Also the Shower only gets proper hot with the immersion heater element switched on.