Plumbing Question - Shower not hot

[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.